Class: Array

Inherits:
Object show all
Includes:
Enumerable
Defined in:
array.c

Overview

Arrays are ordered, integer-indexed collections of any object.

Array indexing starts at 0, as in C or Java. A negative index is assumed to be relative to the end of the array—that is, an index of -1 indicates the last element of the array, -2 is the next to last element in the array, and so on.

Creating Arrays

A new array can be created by using the literal constructor []. Arrays can contain different types of objects. For example, the array below contains an Integer, a String and a Float:

ary = [1, "two", 3.0] #=> [1, "two", 3.0]

An array can also be created by explicitly calling Array.new with zero, one (the initial size of the Array) or two arguments (the initial size and a default object).

ary = Array.new    #=> []
Array.new(3)       #=> [nil, nil, nil]
Array.new(3, true) #=> [true, true, true]

Note that the second argument populates the array with references to the same object. Therefore, it is only recommended in cases when you need to instantiate arrays with natively immutable objects such as Symbols, numbers, true or false.

To create an array with separate objects a block can be passed instead. This method is safe to use with mutable objects such as hashes, strings or other arrays:

Array.new(4) { Hash.new } #=> [{}, {}, {}, {}]

This is also a quick way to build up multi-dimensional arrays:

empty_table = Array.new(3) { Array.new(3) }
#=> [[nil, nil, nil], [nil, nil, nil], [nil, nil, nil]]

An array can also be created by using the Array() method, provided by Kernel, which tries to call #to_ary, then #to_a on its argument.

Array(=> “a”, :b => “b”) #=> [[:a, “a”], [:b, “b”]]

Example Usage

In addition to the methods it mixes in through the Enumerable module, the Array class has proprietary methods for accessing, searching and otherwise manipulating arrays.

Some of the more common ones are illustrated below.

Accessing Elements

Elements in an array can be retrieved using the Array#[] method. It can take a single integer argument (a numeric index), a pair of arguments (start and length) or a range. Negative indices start counting from the end, with -1 being the last element.

arr = [1, 2, 3, 4, 5, 6]
arr[2]    #=> 3
arr[100]  #=> nil
arr[-3]   #=> 4
arr[2, 3] #=> [3, 4, 5]
arr[1..4] #=> [2, 3, 4, 5]
arr[1..-3] #=> [2, 3, 4]

Another way to access a particular array element is by using the #at method

arr.at(0) #=> 1

The #slice method works in an identical manner to Array#[].

To raise an error for indices outside of the array bounds or else to provide a default value when that happens, you can use #fetch.

arr = ['a', 'b', 'c', 'd', 'e', 'f']
arr.fetch(100) #=> IndexError: index 100 outside of array bounds: -6...6
arr.fetch(100, "oops") #=> "oops"

The special methods #first and #last will return the first and last elements of an array, respectively.

arr.first #=> 1
arr.last  #=> 6

To return the first n elements of an array, use #take

arr.take(3) #=> [1, 2, 3]

#drop does the opposite of #take, by returning the elements after n elements have been dropped:

arr.drop(3) #=> [4, 5, 6]

Obtaining Information about an Array

Arrays keep track of their own length at all times. To query an array about the number of elements it contains, use #length, #count or #size.

browsers = ['Chrome', 'Firefox', 'Safari', 'Opera', 'IE']
browsers.length #=> 5
browsers.count #=> 5

To check whether an array contains any elements at all

browsers.empty? #=> false

To check whether a particular item is included in the array

browsers.include?('Konqueror') #=> false

Adding Items to Arrays

Items can be added to the end of an array by using either #push or #<<

arr = [1, 2, 3, 4]
arr.push(5) #=> [1, 2, 3, 4, 5]
arr << 6    #=> [1, 2, 3, 4, 5, 6]

#unshift will add a new item to the beginning of an array.

arr.unshift(0) #=> [0, 1, 2, 3, 4, 5, 6]

With #insert you can add a new element to an array at any position.

arr.insert(3, 'apple')  #=> [0, 1, 2, 'apple', 3, 4, 5, 6]

Using the #insert method, you can also insert multiple values at once:

arr.insert(3, 'orange', 'pear', 'grapefruit')
#=> [0, 1, 2, "orange", "pear", "grapefruit", "apple", 3, 4, 5, 6]

Removing Items from an Array

The method #pop removes the last element in an array and returns it:

arr =  [1, 2, 3, 4, 5, 6]
arr.pop #=> 6
arr #=> [1, 2, 3, 4, 5]

To retrieve and at the same time remove the first item, use #shift:

arr.shift #=> 1
arr #=> [2, 3, 4, 5]

To delete an element at a particular index:

arr.delete_at(2) #=> 4
arr #=> [2, 3, 5]

To delete a particular element anywhere in an array, use #delete:

arr = [1, 2, 2, 3]
arr.delete(2) #=> 2
arr #=> [1,3]

A useful method if you need to remove nil values from an array is #compact:

arr = ['foo', 0, nil, 'bar', 7, 'baz', nil]
arr.compact  #=> ['foo', 0, 'bar', 7, 'baz']
arr          #=> ['foo', 0, nil, 'bar', 7, 'baz', nil]
arr.compact! #=> ['foo', 0, 'bar', 7, 'baz']
arr          #=> ['foo', 0, 'bar', 7, 'baz']

Another common need is to remove duplicate elements from an array.

It has the non-destructive #uniq, and destructive method #uniq!

arr = [2, 5, 6, 556, 6, 6, 8, 9, 0, 123, 556]
arr.uniq #=> [2, 5, 6, 556, 8, 9, 0, 123]

Iterating over Arrays

Like all classes that include the Enumerable module, Array has an each method, which defines what elements should be iterated over and how. In case of Array’s #each, all elements in the Array instance are yielded to the supplied block in sequence.

Note that this operation leaves the array unchanged.

arr = [1, 2, 3, 4, 5]
arr.each { |a| print a -= 10, " " }
# prints: -9 -8 -7 -6 -5
#=> [1, 2, 3, 4, 5]

Another sometimes useful iterator is #reverse_each which will iterate over the elements in the array in reverse order.

words = %w[first second third fourth fifth sixth]
str = ""
words.reverse_each { |word| str += "#{word} " }
p str #=> "sixth fifth fourth third second first "

The #map method can be used to create a new array based on the original array, but with the values modified by the supplied block:

arr.map { |a| 2*a }   #=> [2, 4, 6, 8, 10]
arr                   #=> [1, 2, 3, 4, 5]
arr.map! { |a| a**2 } #=> [1, 4, 9, 16, 25]
arr                   #=> [1, 4, 9, 16, 25]

Selecting Items from an Array

Elements can be selected from an array according to criteria defined in a block. The selection can happen in a destructive or a non-destructive manner. While the destructive operations will modify the array they were called on, the non-destructive methods usually return a new array with the selected elements, but leave the original array unchanged.

Non-destructive Selection

arr = [1, 2, 3, 4, 5, 6]
arr.select { |a| a > 3 }     #=> [4, 5, 6]
arr.reject { |a| a < 3 }     #=> [3, 4, 5, 6]
arr.drop_while { |a| a < 4 } #=> [4, 5, 6]
arr                          #=> [1, 2, 3, 4, 5, 6]

Destructive Selection

#select! and #reject! are the corresponding destructive methods to #select and #reject

Similar to #select vs. #reject, #delete_if and #keep_if have the exact opposite result when supplied with the same block:

arr.delete_if { |a| a < 4 } #=> [4, 5, 6]
arr                         #=> [4, 5, 6]

arr = [1, 2, 3, 4, 5, 6]
arr.keep_if { |a| a < 4 } #=> [1, 2, 3]
arr                       #=> [1, 2, 3]

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#all?, #chunk, #collect_concat, #detect, #each_cons, #each_entry, #each_slice, #each_with_index, #each_with_object, #entries, #find, #find_all, #flat_map, #grep, #group_by, #inject, #lazy, #max, #max_by, #member?, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reduce, #slice_after, #slice_before, #slice_when, #sort_by

Constructor Details

#new(size = 0, default = nil) ⇒ Object #new(array) ⇒ Object #new(size) {|index| ... } ⇒ Object

Returns a new array.

In the first form, if no arguments are sent, the new array will be empty. When a size and an optional default are sent, an array is created with size copies of default. Take notice that all elements will reference the same object default.

The second form creates a copy of the array passed as a parameter (the array is generated by calling to_ary on the parameter).

first_array = ["Matz", "Guido"]

second_array = Array.new(first_array) #=> ["Matz", "Guido"]

first_array.equal? second_array       #=> false

In the last form, an array of the given size is created. Each element in this array is created by passing the element’s index to the given block and storing the return value.

Array.new(3){ |index| index ** 2 }
# => [0, 1, 4]

Common gotchas

When sending the second parameter, the same object will be used as the value for all the array elements:

a = Array.new(2, Hash.new)
# => [{}, {}]

a[0]['cat'] = 'feline'
a # => [{"cat"=>"feline"}, {"cat"=>"feline"}]

a[1]['cat'] = 'Felix'
a # => [{"cat"=>"Felix"}, {"cat"=>"Felix"}]

Since all the Array elements store the same hash, changes to one of them will affect them all.

If multiple copies are what you want, you should use the block version which uses the result of that block each time an element of the array needs to be initialized:

a = Array.new(2) { Hash.new }
a[0]['cat'] = 'feline'
a # => [{"cat"=>"feline"}, {}]

Overloads:



722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
 
# File 'array.c', line 722

static VALUE
rb_ary_initialize(int argc, VALUE *argv, VALUE ary)
{
    long len;
    VALUE size, val;

    rb_ary_modify(ary);
    if (argc == 0) {
	if (ARY_OWNS_HEAP_P(ary) && RARRAY_CONST_PTR(ary) != 0) {
	    ruby_sized_xfree((void *)RARRAY_CONST_PTR(ary), ARY_HEAP_SIZE(ary));
	}
        rb_ary_unshare_safe(ary);
        FL_SET_EMBED(ary);
	ARY_SET_EMBED_LEN(ary, 0);
	if (rb_block_given_p()) {
	    rb_warning("given block not used");
	}
	return ary;
    }
    rb_scan_args(argc, argv, "02", &size, &val);
    if (argc == 1 && !FIXNUM_P(size)) {
	val = rb_check_array_type(size);
	if (!NIL_P(val)) {
	    rb_ary_replace(ary, val);
	    return ary;
	}
    }

    len = NUM2LONG(size);
    /* NUM2LONG() may call size.to_int, ary can be frozen, modified, etc */
    if (len < 0) {
	rb_raise(rb_eArgError, "negative array size");
    }
    if (len > ARY_MAX_SIZE) {
	rb_raise(rb_eArgError, "array size too big");
    }
    /* recheck after argument conversion */
    rb_ary_modify(ary);
    ary_resize_capa(ary, len);
    if (rb_block_given_p()) {
	long i;

	if (argc == 2) {
	    rb_warn("block supersedes default value argument");
	}
	for (i=0; i<len; i++) {
	    rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
	    ARY_SET_LEN(ary, i + 1);
	}
    }
    else {
	ary_memfill(ary, 0, len, val);
	ARY_SET_LEN(ary, len);
    }
    return ary;
}

Class Method Details

.[](*args) ⇒ Object

Returns a new array populated with the given objects.

Array.[]( 1, 'a', /^A/ ) # => [1, "a", /^A/]
Array[ 1, 'a', /^A/ ]    # => [1, "a", /^A/]
[ 1, 'a', /^A/ ]         # => [1, "a", /^A/]



787
788
789
790
791
792
793
794
795
796
797
 
# File 'array.c', line 787

static VALUE
rb_ary_s_create(int argc, VALUE *argv, VALUE klass)
{
    VALUE ary = ary_new(klass, argc);
    if (argc > 0 && argv) {
        ary_memcpy(ary, 0, argc, argv);
        ARY_SET_LEN(ary, argc);
    }

    return ary;
}

.try_convert(obj) ⇒ Array?

Tries to convert obj into an array, using to_ary method. Returns the converted array or nil if obj cannot be converted for any reason. This method can be used to check if an argument is an array.

Array.try_convert([1])   #=> [1]
Array.try_convert("1")   #=> nil

if tmp = Array.try_convert(arg)
  # the argument is an array
elsif tmp = String.try_convert(arg)
  # the argument is a string
end

Returns:



660
661
662
663
664
 
# File 'array.c', line 660

static VALUE
rb_ary_s_try_convert(VALUE dummy, VALUE ary)
{
    return rb_check_array_type(ary);
}

Instance Method Details

#&(other_ary) ⇒ Object

Set Intersection — Returns a new array containing elements common to the two arrays, excluding any duplicates. The order is preserved from the original array.

It compares elements using their #hash and #eql? methods for efficiency.

[ 1, 1, 3, 5 ] & [ 1, 2, 3 ]                 #=> [ 1, 3 ]
[ 'a', 'b', 'b', 'z' ] & [ 'a', 'b', 'c' ]   #=> [ 'a', 'b' ]

See also Array#uniq.



4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
 
# File 'array.c', line 4049

static VALUE
rb_ary_and(VALUE ary1, VALUE ary2)
{
    VALUE hash, ary3, v;
    st_table *table;
    st_data_t vv;
    long i;

    ary2 = to_ary(ary2);
    ary3 = rb_ary_new();
    if (RARRAY_LEN(ary2) == 0) return ary3;
    hash = ary_make_hash(ary2);
    table = rb_hash_tbl_raw(hash);

    for (i=0; i<RARRAY_LEN(ary1); i++) {
	v = RARRAY_AREF(ary1, i);
	vv = (st_data_t)v;
	if (st_delete(table, &vv, 0)) {
	    rb_ary_push(ary3, v);
	}
    }
    ary_recycle_hash(hash);

    return ary3;
}

#*(int) ⇒ Object #*(str) ⇒ Object

Repetition — With a String argument, equivalent to ary.join(str).

Otherwise, returns a new array built by concatenating the int copies of self.

[ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
[ 1, 2, 3 ] * ","  #=> "1,2,3"



3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
 
# File 'array.c', line 3599

static VALUE
rb_ary_times(VALUE ary, VALUE times)
{
    VALUE ary2, tmp;
    const VALUE *ptr;
    long t, len;

    tmp = rb_check_string_type(times);
    if (!NIL_P(tmp)) {
	return rb_ary_join(ary, tmp);
    }

    len = NUM2LONG(times);
    if (len == 0) {
	ary2 = ary_new(rb_obj_class(ary), 0);
	goto out;
    }
    if (len < 0) {
	rb_raise(rb_eArgError, "negative argument");
    }
    if (ARY_MAX_SIZE/len < RARRAY_LEN(ary)) {
	rb_raise(rb_eArgError, "argument too big");
    }
    len *= RARRAY_LEN(ary);

    ary2 = ary_new(rb_obj_class(ary), len);
    ARY_SET_LEN(ary2, len);

    ptr = RARRAY_CONST_PTR(ary);
    t = RARRAY_LEN(ary);
    if (0 < t) {
	ary_memcpy(ary2, 0, t, ptr);
	while (t <= len/2) {
	    ary_memcpy(ary2, t, t, RARRAY_CONST_PTR(ary2));
            t *= 2;
        }
        if (t < len) {
	    ary_memcpy(ary2, t, len-t, RARRAY_CONST_PTR(ary2));
        }
    }
  out:
    OBJ_INFECT(ary2, ary);

    return ary2;
}

#+(other_ary) ⇒ Object

Concatenation — Returns a new array built by concatenating the two arrays together to produce a third array.

[ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]
a = [ "a", "b", "c" ]
c = a + [ "d", "e", "f" ]
c                         #=> [ "a", "b", "c", "d", "e", "f" ]
a                         #=> [ "a", "b", "c" ]

Note that

x += y

is the same as

x = x + y

This means that it produces a new array. As a consequence, repeated use of += on arrays can be quite inefficient.

See also Array#concat.



3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
 
# File 'array.c', line 3538

VALUE
rb_ary_plus(VALUE x, VALUE y)
{
    VALUE z;
    long len, xlen, ylen;

    y = to_ary(y);
    xlen = RARRAY_LEN(x);
    ylen = RARRAY_LEN(y);
    len = xlen + ylen;
    z = rb_ary_new2(len);

    ary_memcpy(z, 0, xlen, RARRAY_CONST_PTR(x));
    ary_memcpy(z, xlen, ylen, RARRAY_CONST_PTR(y));
    ARY_SET_LEN(z, len);
    return z;
}

#-(other_ary) ⇒ Object

Array Difference

Returns a new array that is a copy of the original array, removing any items that also appear in other_ary. The order is preserved from the original array.

It compares elements using their #hash and #eql? methods for efficiency.

[ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]

If you need set-like behavior, see the library class Set.



4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
 
# File 'array.c', line 4014

static VALUE
rb_ary_diff(VALUE ary1, VALUE ary2)
{
    VALUE ary3;
    VALUE hash;
    long i;

    hash = ary_make_hash(to_ary(ary2));
    ary3 = rb_ary_new();

    for (i=0; i<RARRAY_LEN(ary1); i++) {
	if (st_lookup(rb_hash_tbl_raw(hash), RARRAY_AREF(ary1, i), 0)) continue;
	rb_ary_push(ary3, rb_ary_elt(ary1, i));
    }
    ary_recycle_hash(hash);
    return ary3;
}

#<<(obj) ⇒ Object

Append—Pushes the given object on to the end of this array. This expression returns the array itself, so several appends may be chained together.

[ 1, 2 ] << "c" << "d" << [ 3, 4 ]
        #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]



905
906
907
908
909
910
911
912
913
914
915
 
# File 'array.c', line 905

VALUE
rb_ary_push(VALUE ary, VALUE item)
{
    long idx = RARRAY_LEN(ary);
    VALUE target_ary = ary_ensure_room_for_push(ary, 1);
    RARRAY_PTR_USE(ary, ptr, {
	RB_OBJ_WRITE(target_ary, &ptr[idx], item);
    });
    ARY_SET_LEN(ary, idx + 1);
    return ary;
}

#<=>(other_ary) ⇒ -1, ...

Comparison — Returns an integer (-1, 0, or +1) if this array is less than, equal to, or greater than other_ary.

Each object in each array is compared (using the <=> operator).

Arrays are compared in an “element-wise” manner; the first element of ary is compared with the first one of other_ary using the <=> operator, then each of the second elements, etc… As soon as the result of any such comparison is non zero (i.e. the two corresponding elements are not equal), that result is returned for the whole array comparison.

If all the elements are equal, then the result is based on a comparison of the array lengths. Thus, two arrays are “equal” according to Array#<=> if, and only if, they have the same length and the value of each element is equal to the value of the corresponding element in the other array.

nil is returned if the other_ary is not an array or if the comparison of two elements returned nil.

[ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
[ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1
[ 1, 2 ]             <=> [ 1, :two ]         #=> nil

Returns:

  • (-1, 0, +1, nil) 


3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
 
# File 'array.c', line 3918

VALUE
rb_ary_cmp(VALUE ary1, VALUE ary2)
{
    long len;
    VALUE v;

    ary2 = rb_check_array_type(ary2);
    if (NIL_P(ary2)) return Qnil;
    if (ary1 == ary2) return INT2FIX(0);
    v = rb_exec_recursive_paired(recursive_cmp, ary1, ary2, ary2);
    if (v != Qundef) return v;
    len = RARRAY_LEN(ary1) - RARRAY_LEN(ary2);
    if (len == 0) return INT2FIX(0);
    if (len > 0) return INT2FIX(1);
    return INT2FIX(-1);
}

#==(other_ary) ⇒ Boolean

Equality — Two arrays are equal if they contain the same number of elements and if each element is equal to (according to Object#==) the corresponding element in other_ary.

[ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
[ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
[ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false

Returns:

  • (Boolean) 


3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
 
# File 'array.c', line 3761

static VALUE
rb_ary_equal(VALUE ary1, VALUE ary2)
{
    if (ary1 == ary2) return Qtrue;
    if (!RB_TYPE_P(ary2, T_ARRAY)) {
	if (!rb_respond_to(ary2, idTo_ary)) {
	    return Qfalse;
	}
	return rb_equal(ary2, ary1);
    }
    if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
    return rb_exec_recursive_paired(recursive_equal, ary1, ary2, ary2);
}

#[](index) ⇒ Object? #[](start, length) ⇒ nil #[](range) ⇒ nil #slice(index) ⇒ Object? #slice(start, length) ⇒ nil #slice(range) ⇒ nil

Element Reference — Returns the element at index, or returns a subarray starting at the start index and continuing for length elements, or returns a subarray specified by range of indices.

Negative indices count backward from the end of the array (-1 is the last element). For start and range cases the starting index is just before an element. Additionally, an empty array is returned when the starting index for an element range is at the end of the array.

Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[6, 1]                #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

Overloads:

  • #[](index) ⇒ Object?

    Returns:

  • #[](start, length) ⇒ nil

    Returns:

    • (nil)
  • #[](range) ⇒ nil

    Returns:

    • (nil)
  • #slice(index) ⇒ Object?

    Returns:

  • #slice(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice(range) ⇒ nil

    Returns:

    • (nil) 


1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
 
# File 'array.c', line 1248

VALUE
rb_ary_aref(int argc, const VALUE *argv, VALUE ary)
{
    VALUE arg;
    long beg, len;

    if (argc == 2) {
	beg = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
	if (beg < 0) {
	    beg += RARRAY_LEN(ary);
	}
	return rb_ary_subseq(ary, beg, len);
    }
    if (argc != 1) {
	rb_scan_args(argc, argv, "11", NULL, NULL);
    }
    arg = argv[0];
    /* special case - speeding up */
    if (FIXNUM_P(arg)) {
	return rb_ary_entry(ary, FIX2LONG(arg));
    }
    /* check if idx is Range */
    switch (rb_range_beg_len(arg, &beg, &len, RARRAY_LEN(ary), 0)) {
      case Qfalse:
	break;
      case Qnil:
	return Qnil;
      default:
	return rb_ary_subseq(ary, beg, len);
    }
    return rb_ary_entry(ary, NUM2LONG(arg));
}

#[]=(index) ⇒ Object #[]=(start, length) ⇒ Object? #[]=(range) ⇒ Object?

Element Assignment — Sets the element at index, or replaces a subarray from the start index for length elements, or replaces a subarray specified by the range of indices.

If indices are greater than the current capacity of the array, the array grows automatically. Elements are inserted into the array at start if length is zero.

Negative indices will count backward from the end of the array. For start and range cases the starting index is just before an element.

An IndexError is raised if a negative index points past the beginning of the array.

See also Array#push, and Array#unshift.

a = Array.new
a[4] = "4";                 #=> [nil, nil, nil, nil, "4"]
a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
a[1..2] = [ 1, 2 ]          #=> ["a", 1, 2, nil, "4"]
a[0, 2] = "?"               #=> ["?", 2, nil, "4"]
a[0..2] = "A"               #=> ["A", "4"]
a[-1]   = "Z"               #=> ["A", "Z"]
a[1..-1] = nil              #=> ["A", nil]
a[1..-1] = []               #=> ["A"]
a[0, 0] = [ 1, 2 ]          #=> [1, 2, "A"]
a[3, 0] = "B"               #=> [1, 2, "A", "B"]

Overloads:



1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
 
# File 'array.c', line 1703

static VALUE
rb_ary_aset(int argc, VALUE *argv, VALUE ary)
{
    long offset, beg, len;

    if (argc == 3) {
	rb_ary_modify_check(ary);
	beg = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
	rb_ary_splice(ary, beg, len, argv[2]);
	return argv[2];
    }
    rb_check_arity(argc, 2, 2);
    rb_ary_modify_check(ary);
    if (FIXNUM_P(argv[0])) {
	offset = FIX2LONG(argv[0]);
	goto fixnum;
    }
    if (rb_range_beg_len(argv[0], &beg, &len, RARRAY_LEN(ary), 1)) {
	/* check if idx is Range */
	rb_ary_splice(ary, beg, len, argv[1]);
	return argv[1];
    }

    offset = NUM2LONG(argv[0]);
fixnum:
    rb_ary_store(ary, offset, argv[1]);
    return argv[1];
}

#any? {|obj| ... } ⇒ Boolean

See also Enumerable#any?

Yields:

  • (obj)

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
 
# File 'array.c', line 5427

static VALUE
rb_ary_any_p(VALUE ary)
{
    long i, len = RARRAY_LEN(ary);
    const VALUE *ptr = RARRAY_CONST_PTR(ary);

    if (!len) return Qfalse;
    if (!rb_block_given_p()) {
	for (i = 0; i < len; ++i) if (RTEST(ptr[i])) return Qtrue;
    }
    else {
	for (i = 0; i < RARRAY_LEN(ary); ++i) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qtrue;
	}
    }
    return Qfalse;
}

#assoc(obj) ⇒ nil

Searches through an array whose elements are also arrays comparing obj with the first element of each contained array using obj.==.

Returns the first contained array that matches (that is, the first associated array), or nil if no match is found.

See also Array#rassoc

s1 = [ "colors", "red", "blue", "green" ]
s2 = [ "letters", "a", "b", "c" ]
s3 = "foo"
a  = [ s1, s2, s3 ]
a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
a.assoc("foo")      #=> nil

Returns:

  • (nil) 


3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
 
# File 'array.c', line 3665

VALUE
rb_ary_assoc(VALUE ary, VALUE key)
{
    long i;
    VALUE v;

    for (i = 0; i < RARRAY_LEN(ary); ++i) {
	v = rb_check_array_type(RARRAY_AREF(ary, i));
	if (!NIL_P(v) && RARRAY_LEN(v) > 0 &&
	    rb_equal(RARRAY_AREF(v, 0), key))
	    return v;
    }
    return Qnil;
}

#at(index) ⇒ Object?

Returns the element at index. A negative index counts from the end of self. Returns nil if the index is out of range. See also Array#[].

a = [ "a", "b", "c", "d", "e" ]
a.at(0)     #=> "a"
a.at(-1)    #=> "e"

Returns:



1295
1296
1297
1298
1299
 
# File 'array.c', line 1295

static VALUE
rb_ary_at(VALUE ary, VALUE pos)
{
    return rb_ary_entry(ary, NUM2LONG(pos));
}

#bsearch {|x| ... } ⇒ Object

By using binary search, finds a value from this array which meets the given condition in O(log n) where n is the size of the array.

You can use this method in two use cases: a find-minimum mode and a find-any mode. In either case, the elements of the array must be monotone (or sorted) with respect to the block.

In find-minimum mode (this is a good choice for typical use case), the block must return true or false, and there must be an index i (0 <= i <= ary.size) so that:

  • the block returns false for any element whose index is less than i, and

  • the block returns true for any element whose index is greater than or equal to i.

This method returns the i-th element. If i is equal to ary.size, it returns nil.

ary = [0, 4, 7, 10, 12]
ary.bsearch {|x| x >=   4 } #=> 4
ary.bsearch {|x| x >=   6 } #=> 7
ary.bsearch {|x| x >=  -1 } #=> 0
ary.bsearch {|x| x >= 100 } #=> nil

In find-any mode (this behaves like libc’s bsearch(3)), the block must return a number, and there must be two indices i and j (0 <= i <= j <= ary.size) so that:

  • the block returns a positive number for ary if 0 <= k < i,

  • the block returns zero for ary if i <= k < j, and

  • the block returns a negative number for ary if j <= k < ary.size.

Under this condition, this method returns any element whose index is within i…j. If i is equal to j (i.e., there is no element that satisfies the block), this method returns nil.

ary = [0, 4, 7, 10, 12]
# try to find v such that 4 <= v < 8
ary.bsearch {|x| 1 - x / 4 } #=> 4 or 7
# try to find v such that 8 <= v < 10
ary.bsearch {|x| 4 - x / 2 } #=> nil

You must not mix the two modes at a time; the block must always return either true/false, or always return a number. It is undefined which value is actually picked up at each iteration.

Yields:

  • (x) 


2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
 
# File 'array.c', line 2585

static VALUE
rb_ary_bsearch(VALUE ary)
{
    long low = 0, high = RARRAY_LEN(ary), mid;
    int smaller = 0, satisfied = 0;
    VALUE v, val;

    RETURN_ENUMERATOR(ary, 0, 0);
    while (low < high) {
	mid = low + ((high - low) / 2);
	val = rb_ary_entry(ary, mid);
	v = rb_yield(val);
	if (FIXNUM_P(v)) {
	    if (FIX2INT(v) == 0) return val;
	    smaller = FIX2INT(v) < 0;
	}
	else if (v == Qtrue) {
	    satisfied = 1;
	    smaller = 1;
	}
	else if (v == Qfalse || v == Qnil) {
	    smaller = 0;
	}
	else if (rb_obj_is_kind_of(v, rb_cNumeric)) {
	    const VALUE zero = INT2FIX(0);
	    switch (rb_cmpint(rb_funcallv(v, id_cmp, 1, &zero), v, INT2FIX(0))) {
		case 0: return val;
		case 1: smaller = 1; break;
		case -1: smaller = 0;
	    }
	}
	else {
	    rb_raise(rb_eTypeError, "wrong argument type %s"
		" (must be numeric, true, false or nil)",
		rb_obj_classname(v));
	}
	if (smaller) {
	    high = mid;
	}
	else {
	    low = mid + 1;
	}
    }
    if (low == RARRAY_LEN(ary)) return Qnil;
    if (!satisfied) return Qnil;
    return rb_ary_entry(ary, low);
}

#clear ⇒ Object

Removes all elements from self.

a = [ "a", "b", "c", "d", "e" ]
a.clear    #=> [ ]



3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
 
# File 'array.c', line 3402

VALUE
rb_ary_clear(VALUE ary)
{
    rb_ary_modify_check(ary);
    ARY_SET_LEN(ary, 0);
    if (ARY_SHARED_P(ary)) {
	if (!ARY_EMBED_P(ary)) {
	    rb_ary_unshare(ary);
	    FL_SET_EMBED(ary);
	}
    }
    else if (ARY_DEFAULT_SIZE * 2 < ARY_CAPA(ary)) {
	ary_resize_capa(ary, ARY_DEFAULT_SIZE * 2);
    }
    return ary;
}

#collect {|item| ... } ⇒ Object #map {|item| ... } ⇒ Object #collect ⇒ Enumerator #map ⇒ Enumerator

Invokes the given block once for each element of self.

Creates a new array containing the values returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.collect { |x| x + "!" }        #=> ["a!", "b!", "c!", "d!"]
a.map.with_index{ |x, i| x * i } #=> ["", "b", "cc", "ddd"]
a                                #=> ["a", "b", "c", "d"]

Overloads:



2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
 
# File 'array.c', line 2686

static VALUE
rb_ary_collect(VALUE ary)
{
    long i;
    VALUE collect;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    collect = rb_ary_new2(RARRAY_LEN(ary));
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
    }
    return collect;
}

#collect! {|item| ... } ⇒ Object #map! {|item| ... } ⇒ Object #collect! ⇒ Enumerator #map! ⇒ Enumerator

Invokes the given block once for each element of self, replacing the element with the value returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.map! {|x| x + "!" }
a #=>  [ "a!", "b!", "c!", "d!" ]
a.collect!.with_index {|x, i| x[0...i] }
a #=>  ["", "b", "c!", "d!"]

Overloads:



2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
 
# File 'array.c', line 2722

static VALUE
rb_ary_collect_bang(VALUE ary)
{
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
    }
    return ary;
}

#combination(n) {|c| ... } ⇒ Object #combination(n) ⇒ Enumerator

When invoked with a block, yields all combinations of length n of elements from the array and then returns the array itself.

The implementation makes no guarantees about the order in which the combinations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3, 4]
a.combination(1).to_a  #=> [[1],[2],[3],[4]]
a.combination(2).to_a  #=> [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
a.combination(3).to_a  #=> [[1,2,3],[1,2,4],[1,3,4],[2,3,4]]
a.combination(4).to_a  #=> [[1,2,3,4]]
a.combination(0).to_a  #=> [[]] # one combination of length 0
a.combination(5).to_a  #=> []   # no combinations of length 5

Overloads:



4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
 
# File 'array.c', line 4962

static VALUE
rb_ary_combination(VALUE ary, VALUE num)
{
    long i, n, len;

    n = NUM2LONG(num);
    RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_combination_size);
    len = RARRAY_LEN(ary);
    if (n < 0 || len < n) {
	/* yield nothing */
    }
    else if (n == 0) {
	rb_yield(rb_ary_new2(0));
    }
    else if (n == 1) {
	for (i = 0; i < len; i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else {
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	volatile VALUE t0;
	long *stack = ALLOCV_N(long, t0, n+1);

	RBASIC_CLEAR_CLASS(ary0);
	combinate0(len, n, stack, ary0);
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#compact ⇒ Object

Returns a copy of self with all nil elements removed.

[ "a", nil, "b", nil, "c", nil ].compact
                  #=> [ "a", "b", "c" ]



4265
4266
4267
4268
4269
4270
4271
 
# File 'array.c', line 4265

static VALUE
rb_ary_compact(VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_compact_bang(ary);
    return ary;
}

#compact! ⇒ nil

Removes nil elements from the array.

Returns nil if no changes were made, otherwise returns the array.

[ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
[ "a", "b", "c" ].compact!           #=> nil

Returns:

  • (nil) 


4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
 
# File 'array.c', line 4232

static VALUE
rb_ary_compact_bang(VALUE ary)
{
    VALUE *p, *t, *end;
    long n;

    rb_ary_modify(ary);
    p = t = (VALUE *)RARRAY_CONST_PTR(ary); /* WB: no new reference */
    end = p + RARRAY_LEN(ary);

    while (t < end) {
	if (NIL_P(*t)) t++;
	else *p++ = *t++;
    }
    n = p - RARRAY_CONST_PTR(ary);
    if (RARRAY_LEN(ary) == n) {
	return Qnil;
    }
    ary_resize_smaller(ary, n);

    return ary;
}

#concat(other_ary) ⇒ Object

Appends the elements of other_ary to self.

[ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
a = [ 1, 2, 3 ]
a.concat( [ 4, 5 ] )
a                                 #=> [ 1, 2, 3, 4, 5 ]

See also Array#+.



3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
 
# File 'array.c', line 3570

VALUE
rb_ary_concat(VALUE x, VALUE y)
{
    rb_ary_modify_check(x);
    y = to_ary(y);
    if (RARRAY_LEN(y) > 0) {
	rb_ary_splice(x, RARRAY_LEN(x), 0, y);
    }
    return x;
}

#count ⇒ Integer #count(obj) ⇒ Integer #count {|item| ... } ⇒ Integer

Returns the number of elements.

If an argument is given, counts the number of elements which equal obj using ==.

If a block is given, counts the number of elements for which the block returns a true value.

ary = [1, 2, 4, 2]
ary.count                  #=> 4
ary.count(2)               #=> 2
ary.count { |x| x%2 == 0 } #=> 3

Overloads:



4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
 
# File 'array.c', line 4294

static VALUE
rb_ary_count(int argc, VALUE *argv, VALUE ary)
{
    long i, n = 0;

    if (argc == 0) {
	VALUE v;

	if (!rb_block_given_p())
	    return LONG2NUM(RARRAY_LEN(ary));

	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    v = RARRAY_AREF(ary, i);
	    if (RTEST(rb_yield(v))) n++;
	}
    }
    else {
	VALUE obj;

	rb_scan_args(argc, argv, "1", &obj);
	if (rb_block_given_p()) {
	    rb_warn("given block not used");
	}
	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
	}
    }

    return LONG2NUM(n);
}

#cycle(n = nil) {|obj| ... } ⇒ nil #cycle(n = nil) ⇒ Enumerator

Calls the given block for each element n times or forever if nil is given.

Does nothing if a non-positive number is given or the array is empty.

Returns nil if the loop has finished without getting interrupted.

If no block is given, an Enumerator is returned instead.

a = ["a", "b", "c"]
a.cycle { |x| puts x }     # print, a, b, c, a, b, c,.. forever.
a.cycle(2) { |x| puts x }  # print, a, b, c, a, b, c.

Overloads:

  • #cycle(n = nil) {|obj| ... } ⇒ nil

    Yields:

    • (obj)

    Returns:

    • (nil)
  • #cycle(n = nil) ⇒ Enumerator

    Returns:



4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
 
# File 'array.c', line 4706

static VALUE
rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
{
    long n, i;
    VALUE nv = Qnil;

    rb_scan_args(argc, argv, "01", &nv);

    RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_cycle_size);
    if (NIL_P(nv)) {
        n = -1;
    }
    else {
        n = NUM2LONG(nv);
        if (n <= 0) return Qnil;
    }

    while (RARRAY_LEN(ary) > 0 && (n < 0 || 0 < n--)) {
        for (i=0; i<RARRAY_LEN(ary); i++) {
            rb_yield(RARRAY_AREF(ary, i));
        }
    }
    return Qnil;
}

#delete(obj) ⇒ nil #delete(obj) { ... } ⇒ Object

Deletes all items from self that are equal to obj.

Returns the last deleted item, or nil if no matching item is found.

If the optional code block is given, the result of the block is returned if the item is not found. (To remove nil elements and get an informative return value, use Array#compact!)

a = [ "a", "b", "b", "b", "c" ]
a.delete("b")                   #=> "b"
a                               #=> ["a", "c"]
a.delete("z")                   #=> nil
a.delete("z") { "not found" }   #=> "not found"

Overloads:

  • #delete(obj) ⇒ nil

    Returns:

    • (nil)
  • #delete(obj) { ... } ⇒ Object

    Yields:



2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
 
# File 'array.c', line 2915

VALUE
rb_ary_delete(VALUE ary, VALUE item)
{
    VALUE v = item;
    long i1, i2;

    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
	VALUE e = RARRAY_AREF(ary, i1);

	if (rb_equal(e, item)) {
	    v = e;
	    continue;
	}
	if (i1 != i2) {
	    rb_ary_store(ary, i2, e);
	}
	i2++;
    }
    if (RARRAY_LEN(ary) == i2) {
	if (rb_block_given_p()) {
	    return rb_yield(item);
	}
	return Qnil;
    }

    ary_resize_smaller(ary, i2);

    return v;
}

#delete_at(index) ⇒ Object?

Deletes the element at the specified index, returning that element, or nil if the index is out of range.

See also Array#slice!

a = ["ant", "bat", "cat", "dog"]
a.delete_at(2)    #=> "cat"
a                 #=> ["ant", "bat", "dog"]
a.delete_at(99)   #=> nil

Returns:



3005
3006
3007
3008
3009
 
# File 'array.c', line 3005

static VALUE
rb_ary_delete_at_m(VALUE ary, VALUE pos)
{
    return rb_ary_delete_at(ary, NUM2LONG(pos));
}

#delete_if {|item| ... } ⇒ Object #delete_if ⇒ Enumerator

Deletes every element of self for which block evaluates to true.

The array is changed instantly every time the block is called, not after the iteration is over.

See also Array#reject!

If no block is given, an Enumerator is returned instead.

scores = [ 97, 42, 75 ]
scores.delete_if {|score| score < 80 }   #=> [97]

Overloads:



3182
3183
3184
3185
3186
3187
3188
 
# File 'array.c', line 3182

static VALUE
rb_ary_delete_if(VALUE ary)
{
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    ary_reject_bang(ary);
    return ary;
}

#drop(n) ⇒ Object

Drops first n elements from ary and returns the rest of the elements in an array.

If a negative number is given, raises an ArgumentError.

See also Array#take

a = [1, 2, 3, 4, 5, 0]
a.drop(3)             #=> [4, 5, 0]



5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
 
# File 'array.c', line 5376

static VALUE
rb_ary_drop(VALUE ary, VALUE n)
{
    VALUE result;
    long pos = NUM2LONG(n);
    if (pos < 0) {
	rb_raise(rb_eArgError, "attempt to drop negative size");
    }

    result = rb_ary_subseq(ary, pos, RARRAY_LEN(ary));
    if (result == Qnil) result = rb_ary_new();
    return result;
}

#drop_while {|arr| ... } ⇒ Object #drop_while ⇒ Enumerator

Drops elements up to, but not including, the first element for which the block returns nil or false and returns an array containing the remaining elements.

If no block is given, an Enumerator is returned instead.

See also Array#take_while

a = [1, 2, 3, 4, 5, 0]
a.drop_while {|i| i < 3 }   #=> [3, 4, 5, 0]

Overloads:



5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
 
# File 'array.c', line 5408

static VALUE
rb_ary_drop_while(VALUE ary)
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
    }
    return rb_ary_drop(ary, LONG2FIX(i));
}

#each {|item| ... } ⇒ Object #each ⇒ Enumerator

Calls the given block once for each element in self, passing that element as a parameter.

An Enumerator is returned if no block is given.

a = [ "a", "b", "c" ]
a.each {|x| print x, " -- " }

produces:

a -- b -- c --

Overloads:



1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
 
# File 'array.c', line 1795

VALUE
rb_ary_each(VALUE array)
{
    long i;
    volatile VALUE ary = array;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    for (i=0; i<RARRAY_LEN(ary); i++) {
	rb_yield(RARRAY_AREF(ary, i));
    }
    return ary;
}

#each_index {|index| ... } ⇒ Object #each_index ⇒ Enumerator

Same as Array#each, but passes the index of the element instead of the element itself.

An Enumerator is returned if no block is given.

a = [ "a", "b", "c" ]
a.each_index {|x| print x, " -- " }

produces:

0 -- 1 -- 2 --

Overloads:



1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
 
# File 'array.c', line 1826

static VALUE
rb_ary_each_index(VALUE ary)
{
    long i;
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);

    for (i=0; i<RARRAY_LEN(ary); i++) {
	rb_yield(LONG2NUM(i));
    }
    return ary;
}

#empty? ⇒ Boolean

Returns true if self contains no elements.

[].empty?   #=> true

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


1897
1898
1899
1900
1901
1902
1903
 
# File 'array.c', line 1897

static VALUE
rb_ary_empty_p(VALUE ary)
{
    if (RARRAY_LEN(ary) == 0)
	return Qtrue;
    return Qfalse;
}

#eql?(other) ⇒ Boolean

Returns true if self and other are the same object, or are both arrays with the same content (according to Object#eql?).

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


3797
3798
3799
3800
3801
3802
3803
3804
3805
 
# File 'array.c', line 3797

static VALUE
rb_ary_eql(VALUE ary1, VALUE ary2)
{
    if (ary1 == ary2) return Qtrue;
    if (!RB_TYPE_P(ary2, T_ARRAY)) return Qfalse;
    if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
    return rb_exec_recursive_paired(recursive_eql, ary1, ary2, ary2);
}

#fetch(index) ⇒ Object #fetch(index, default) ⇒ Object #fetch(index) {|index| ... } ⇒ Object

Tries to return the element at position index, but throws an IndexError exception if the referenced index lies outside of the array bounds. This error can be prevented by supplying a second argument, which will act as a default value.

Alternatively, if a block is given it will only be executed when an invalid index is referenced. Negative values of index count from the end of the array.

a = [ 11, 22, 33, 44 ]
a.fetch(1)               #=> 22
a.fetch(-1)              #=> 44
a.fetch(4, 'cat')        #=> "cat"
a.fetch(100) { |i| puts "#{i} is out of bounds" }
                         #=> "100 is out of bounds"

Overloads:



1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
 
# File 'array.c', line 1379

static VALUE
rb_ary_fetch(int argc, VALUE *argv, VALUE ary)
{
    VALUE pos, ifnone;
    long block_given;
    long idx;

    rb_scan_args(argc, argv, "11", &pos, &ifnone);
    block_given = rb_block_given_p();
    if (block_given && argc == 2) {
	rb_warn("block supersedes default value argument");
    }
    idx = NUM2LONG(pos);

    if (idx < 0) {
	idx +=  RARRAY_LEN(ary);
    }
    if (idx < 0 || RARRAY_LEN(ary) <= idx) {
	if (block_given) return rb_yield(pos);
	if (argc == 1) {
	    rb_raise(rb_eIndexError, "index %ld outside of array bounds: %ld...%ld",
			idx - (idx < 0 ? RARRAY_LEN(ary) : 0), -RARRAY_LEN(ary), RARRAY_LEN(ary));
	}
	return ifnone;
    }
    return RARRAY_AREF(ary, idx);
}

#fill(obj) ⇒ Object #fill(obj, start[, length]) ⇒ Object #fill(obj, range) ⇒ Object #fill {|index| ... } ⇒ Object #fill(start[, length]) {|index| ... } ⇒ Object #fill(range) {|index| ... } ⇒ Object

The first three forms set the selected elements of self (which may be the entire array) to obj.

A start of nil is equivalent to zero.

A length of nil is equivalent to the length of the array.

The last three forms fill the array with the value of the given block, which is passed the absolute index of each element to be filled.

Negative values of start count from the end of the array, where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.fill("x")              #=> ["x", "x", "x", "x"]
a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
a.fill { |i| i*i }       #=> [0, 1, 4, 9]
a.fill(-2) { |i| i*i*i } #=> [0, 1, 8, 27]

Overloads:

  • #fill {|index| ... } ⇒ Object

    Yields:

  • #fill(start[, length]) {|index| ... } ⇒ Object

    Yields:

  • #fill(range) {|index| ... } ⇒ Object

    Yields:



3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
 
# File 'array.c', line 3449

static VALUE
rb_ary_fill(int argc, VALUE *argv, VALUE ary)
{
    VALUE item, arg1, arg2;
    long beg = 0, end = 0, len = 0;
    int block_p = FALSE;

    if (rb_block_given_p()) {
	block_p = TRUE;
	rb_scan_args(argc, argv, "02", &arg1, &arg2);
	argc += 1;		/* hackish */
    }
    else {
	rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
    }
    switch (argc) {
      case 1:
	beg = 0;
	len = RARRAY_LEN(ary);
	break;
      case 2:
	if (rb_range_beg_len(arg1, &beg, &len, RARRAY_LEN(ary), 1)) {
	    break;
	}
	/* fall through */
      case 3:
	beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
	if (beg < 0) {
	    beg = RARRAY_LEN(ary) + beg;
	    if (beg < 0) beg = 0;
	}
	len = NIL_P(arg2) ? RARRAY_LEN(ary) - beg : NUM2LONG(arg2);
	break;
    }
    rb_ary_modify(ary);
    if (len < 0) {
        return ary;
    }
    if (beg >= ARY_MAX_SIZE || len > ARY_MAX_SIZE - beg) {
	rb_raise(rb_eArgError, "argument too big");
    }
    end = beg + len;
    if (RARRAY_LEN(ary) < end) {
	if (end >= ARY_CAPA(ary)) {
	    ary_resize_capa(ary, end);
	}
	ary_mem_clear(ary, RARRAY_LEN(ary), end - RARRAY_LEN(ary));
	ARY_SET_LEN(ary, end);
    }

    if (block_p) {
	VALUE v;
	long i;

	for (i=beg; i<end; i++) {
	    v = rb_yield(LONG2NUM(i));
	    if (i>=RARRAY_LEN(ary)) break;
	    ARY_SET(ary, i, v);
	}
    }
    else {
	ary_memfill(ary, beg, len, item);
    }
    return ary;
}

#find_index(obj) ⇒ Integer? #find_index {|item| ... } ⇒ Integer? #find_index ⇒ Enumerator #index(obj) ⇒ Integer? #index {|item| ... } ⇒ Integer? #index ⇒ Enumerator

Returns the index of the first object in ary such that the object is == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true. Returns nil if no match is found.

See also Array#rindex.

An Enumerator is returned if neither a block nor argument is given.

a = [ "a", "b", "c" ]
a.index("b")              #=> 1
a.index("z")              #=> nil
a.index { |x| x == "b" }  #=> 1

Overloads:



1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
 
# File 'array.c', line 1433

static VALUE
rb_ary_index(int argc, VALUE *argv, VALUE ary)
{
    const VALUE *ptr;
    VALUE val;
    long i, len;

    if (argc == 0) {
	RETURN_ENUMERATOR(ary, 0, 0);
	for (i=0; i<RARRAY_LEN(ary); i++) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
		return LONG2NUM(i);
	    }
	}
	return Qnil;
    }
    rb_check_arity(argc, 0, 1);
    val = argv[0];
    if (rb_block_given_p())
	rb_warn("given block not used");
    len = RARRAY_LEN(ary);
    ptr = RARRAY_CONST_PTR(ary);
    for (i=0; i<len; i++) {
	VALUE e = ptr[i];
	switch (rb_equal_opt(e, val)) {
	  case Qundef:
	    if (!rb_equal(e, val)) break;
	  case Qtrue:
	    return LONG2NUM(i);
	  case Qfalse:
	    continue;
	}
	len = RARRAY_LEN(ary);
	ptr = RARRAY_CONST_PTR(ary);
    }
    return Qnil;
}

#first ⇒ Object? #first(n) ⇒ Object

Returns the first element, or the first n elements, of the array. If the array is empty, the first form returns nil, and the second form returns an empty array. See also Array#last for the opposite effect.

a = [ "q", "r", "s", "t" ]
a.first     #=> "q"
a.first(2)  #=> ["q", "r"]

Overloads:



1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
 
# File 'array.c', line 1316

static VALUE
rb_ary_first(int argc, VALUE *argv, VALUE ary)
{
    if (argc == 0) {
	if (RARRAY_LEN(ary) == 0) return Qnil;
	return RARRAY_AREF(ary, 0);
    }
    else {
	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
    }
}

#flatten ⇒ Object #flatten(level) ⇒ Object

Returns a new array that is a one-dimensional flattening of self (recursively).

That is, for every element that is an array, extract its elements into the new array.

The optional level argument determines the level of recursion to flatten.

s = [ 1, 2, 3 ]           #=> [1, 2, 3]
t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten(1)              #=> [1, 2, 3, [4, 5]]



4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
 
# File 'array.c', line 4444

static VALUE
rb_ary_flatten(int argc, VALUE *argv, VALUE ary)
{
    int mod = 0, level = -1;
    VALUE result, lv;

    rb_scan_args(argc, argv, "01", &lv);
    if (!NIL_P(lv)) level = NUM2INT(lv);
    if (level == 0) return ary_make_shared_copy(ary);

    result = flatten(ary, level, &mod);
    OBJ_INFECT(result, ary);

    return result;
}

#flatten! ⇒ nil #flatten!(level) ⇒ nil

Flattens self in place.

Returns nil if no modifications were made (i.e., the array contains no subarrays.)

The optional level argument determines the level of recursion to flatten.

a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!   #=> [1, 2, 3, 4, 5]
a.flatten!   #=> nil
a            #=> [1, 2, 3, 4, 5]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!(1) #=> [1, 2, 3, [4, 5]]

Overloads:

  • #flatten! ⇒ nil

    Returns:

    • (nil)
  • #flatten!(level) ⇒ nil

    Returns:

    • (nil) 


4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
 
# File 'array.c', line 4399

static VALUE
rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
{
    int mod = 0, level = -1;
    VALUE result, lv;

    rb_scan_args(argc, argv, "01", &lv);
    rb_ary_modify_check(ary);
    if (!NIL_P(lv)) level = NUM2INT(lv);
    if (level == 0) return Qnil;

    result = flatten(ary, level, &mod);
    if (mod == 0) {
	ary_discard(result);
	return Qnil;
    }
    if (!(mod = ARY_EMBED_P(result))) rb_obj_freeze(result);
    rb_ary_replace(ary, result);
    if (mod) ARY_SET_EMBED_LEN(result, 0);

    return ary;
}

#frozen? ⇒ Boolean

Return true if this array is frozen (or temporarily frozen while being sorted). See also Object#frozen?

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


412
413
414
415
416
417
 
# File 'array.c', line 412

static VALUE
rb_ary_frozen_p(VALUE ary)
{
    if (OBJ_FROZEN(ary)) return Qtrue;
    return Qfalse;
}

#hash ⇒ Fixnum

Compute a hash-code for this array.

Two arrays with the same content will have the same hash code (and will compare using #eql?).

See also Object#hash.

Returns:



3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
 
# File 'array.c', line 3819

static VALUE
rb_ary_hash(VALUE ary)
{
    long i;
    st_index_t h;
    VALUE n;

    h = rb_hash_start(RARRAY_LEN(ary));
    h = rb_hash_uint(h, (st_index_t)rb_ary_hash);
    for (i=0; i<RARRAY_LEN(ary); i++) {
	n = rb_hash(RARRAY_AREF(ary, i));
	h = rb_hash_uint(h, NUM2LONG(n));
    }
    h = rb_hash_end(h);
    return LONG2FIX(h);
}

#include?(object) ⇒ Boolean

Returns true if the given object is present in self (that is, if any element == object), otherwise returns false.

a = [ "a", "b", "c" ]
a.include?("b")   #=> true
a.include?("z")   #=> false

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
 
# File 'array.c', line 3848

VALUE
rb_ary_includes(VALUE ary, VALUE item)
{
    long i;
    VALUE e;

    for (i=0; i<RARRAY_LEN(ary); i++) {
	e = RARRAY_AREF(ary, i);
	switch (rb_equal_opt(e, item)) {
	  case Qundef:
	    if (rb_equal(e, item)) return Qtrue;
	    break;
	  case Qtrue:
	    return Qtrue;
	}
    }
    return Qfalse;
}

#find_index(obj) ⇒ Integer? #find_index {|item| ... } ⇒ Integer? #find_index ⇒ Enumerator #index(obj) ⇒ Integer? #index {|item| ... } ⇒ Integer? #index ⇒ Enumerator

Returns the index of the first object in ary such that the object is == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true. Returns nil if no match is found.

See also Array#rindex.

An Enumerator is returned if neither a block nor argument is given.

a = [ "a", "b", "c" ]
a.index("b")              #=> 1
a.index("z")              #=> nil
a.index { |x| x == "b" }  #=> 1

Overloads:



1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
 
# File 'array.c', line 1433

static VALUE
rb_ary_index(int argc, VALUE *argv, VALUE ary)
{
    const VALUE *ptr;
    VALUE val;
    long i, len;

    if (argc == 0) {
	RETURN_ENUMERATOR(ary, 0, 0);
	for (i=0; i<RARRAY_LEN(ary); i++) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
		return LONG2NUM(i);
	    }
	}
	return Qnil;
    }
    rb_check_arity(argc, 0, 1);
    val = argv[0];
    if (rb_block_given_p())
	rb_warn("given block not used");
    len = RARRAY_LEN(ary);
    ptr = RARRAY_CONST_PTR(ary);
    for (i=0; i<len; i++) {
	VALUE e = ptr[i];
	switch (rb_equal_opt(e, val)) {
	  case Qundef:
	    if (!rb_equal(e, val)) break;
	  case Qtrue:
	    return LONG2NUM(i);
	  case Qfalse:
	    continue;
	}
	len = RARRAY_LEN(ary);
	ptr = RARRAY_CONST_PTR(ary);
    }
    return Qnil;
}

#replace(other_ary) ⇒ Object #initialize_copy(other_ary) ⇒ Object

Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]



3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
 
# File 'array.c', line 3352

VALUE
rb_ary_replace(VALUE copy, VALUE orig)
{
    rb_ary_modify_check(copy);
    orig = to_ary(orig);
    if (copy == orig) return copy;

    if (RARRAY_LEN(orig) <= RARRAY_EMBED_LEN_MAX) {
        VALUE shared = 0;

        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
	}
        else if (ARY_SHARED_P(copy)) {
            shared = ARY_SHARED(copy);
            FL_UNSET_SHARED(copy);
        }
        FL_SET_EMBED(copy);
	ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR(orig));
        if (shared) {
            rb_ary_decrement_share(shared);
        }
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
    }
    else {
        VALUE shared = ary_make_shared(orig);
        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
        }
        else {
            rb_ary_unshare_safe(copy);
        }
        FL_UNSET_EMBED(copy);
        ARY_SET_PTR(copy, RARRAY_CONST_PTR(orig));
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
        rb_ary_set_shared(copy, shared);
    }
    return copy;
}

#insert(index, obj...) ⇒ Object

Inserts the given values before the element with the given index.

Negative indices count backwards from the end of the array, where -1 is the last element. If a negative index is used, the given values will be inserted after that element, so using an index of -1 will insert the values at the end of the array.

a = %w{ a b c d }
a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]



1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
 
# File 'array.c', line 1749

static VALUE
rb_ary_insert(int argc, VALUE *argv, VALUE ary)
{
    long pos;

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    rb_ary_modify_check(ary);
    if (argc == 1) return ary;
    pos = NUM2LONG(argv[0]);
    if (pos == -1) {
	pos = RARRAY_LEN(ary);
    }
    if (pos < 0) {
	pos++;
    }
    rb_ary_splice(ary, pos, 0, rb_ary_new4(argc - 1, argv + 1));
    return ary;
}

#inspect ⇒ String #to_s ⇒ String Also known as: to_s

Creates a string representation of self.

[ "a", "b", "c" ].to_s     #=> "[\"a\", \"b\", \"c\"]"

Overloads:



2106
2107
2108
2109
2110
2111
 
# File 'array.c', line 2106

static VALUE
rb_ary_inspect(VALUE ary)
{
    if (RARRAY_LEN(ary) == 0) return rb_usascii_str_new2("[]");
    return rb_exec_recursive(inspect_ary, ary, 0);
}

#join(separator = $,) ⇒ String

Returns a string created by converting each element of the array to a string, separated by the given separator. If the separator is nil, it uses current $,. If both the separator and $, are nil, it uses empty string.

[ "a", "b", "c" ].join        #=> "abc"
[ "a", "b", "c" ].join("-")   #=> "a-b-c"

Returns:



2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
 
# File 'array.c', line 2064

static VALUE
rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE sep;

    rb_scan_args(argc, argv, "01", &sep);
    if (NIL_P(sep)) sep = rb_output_fs;

    return rb_ary_join(ary, sep);
}

#keep_if {|item| ... } ⇒ Object #keep_if ⇒ Enumerator

Deletes every element of self for which the given block evaluates to false.

See also Array#select!

If no block is given, an Enumerator is returned instead.

a = %w{ a b c d e f }
a.keep_if { |v| v =~ /[aeiou]/ }  #=> ["a", "e"]

Overloads:



2874
2875
2876
2877
2878
2879
2880
 
# File 'array.c', line 2874

static VALUE
rb_ary_keep_if(VALUE ary)
{
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_select_bang(ary);
    return ary;
}

#last ⇒ Object? #last(n) ⇒ Object

Returns the last element(s) of self. If the array is empty, the first form returns nil.

See also Array#first for the opposite effect.

a = [ "w", "x", "y", "z" ]
a.last     #=> "z"
a.last(2)  #=> ["y", "z"]

Overloads:



1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
 
# File 'array.c', line 1343

VALUE
rb_ary_last(int argc, const VALUE *argv, VALUE ary)
{
    if (argc == 0) {
	long len = RARRAY_LEN(ary);
	if (len == 0) return Qnil;
	return RARRAY_AREF(ary, len-1);
    }
    else {
	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
    }
}

#length ⇒ Integer Also known as: size

Returns the number of elements in self. May be zero.

[ 1, 2, 3, 4, 5 ].length   #=> 5
[].length                  #=> 0

Returns:



1881
1882
1883
1884
1885
1886
 
# File 'array.c', line 1881

static VALUE
rb_ary_length(VALUE ary)
{
    long len = RARRAY_LEN(ary);
    return LONG2NUM(len);
}

#collect {|item| ... } ⇒ Object #map {|item| ... } ⇒ Object #collect ⇒ Enumerator #map ⇒ Enumerator

Invokes the given block once for each element of self.

Creates a new array containing the values returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.collect { |x| x + "!" }        #=> ["a!", "b!", "c!", "d!"]
a.map.with_index{ |x, i| x * i } #=> ["", "b", "cc", "ddd"]
a                                #=> ["a", "b", "c", "d"]

Overloads:



2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
 
# File 'array.c', line 2686

static VALUE
rb_ary_collect(VALUE ary)
{
    long i;
    VALUE collect;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    collect = rb_ary_new2(RARRAY_LEN(ary));
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
    }
    return collect;
}

#collect! {|item| ... } ⇒ Object #map! {|item| ... } ⇒ Object #collect! ⇒ Enumerator #map! ⇒ Enumerator

Invokes the given block once for each element of self, replacing the element with the value returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.map! {|x| x + "!" }
a #=>  [ "a!", "b!", "c!", "d!" ]
a.collect!.with_index {|x, i| x[0...i] }
a #=>  ["", "b", "c!", "d!"]

Overloads:



2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
 
# File 'array.c', line 2722

static VALUE
rb_ary_collect_bang(VALUE ary)
{
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
    }
    return ary;
}

#pack(fmt) ⇒ Object

Packs the contents of arr into a binary sequence according to the directives in aTemplateString (see the table below) Directives “A,” “a,” and “Z” may be followed by a count, which gives the width of the resulting field. The remaining directives also may take a count, indicating the number of array elements to convert. If the count is an asterisk (“*”), all remaining array elements will be converted. Any of the directives “sSiIlL” may be followed by an underscore (“_”) or exclamation mark (“!”) to use the underlying platform’s native size for the specified type; otherwise, they use a platform-independent size. Spaces are ignored in the template string. See also String#unpack.

a = [ "a", "b", "c" ]
n = [ 65, 66, 67 ]
a.pack("A3A3A3")   #=> "a  b  c  "
a.pack("a3a3a3")   #=> "a\000\000b\000\000c\000\000"
n.pack("ccc")      #=> "ABC"

Directives for pack.

Integer      | Array   |
Directive    | Element | Meaning
---------------------------------------------------------------------------
   C         | Integer | 8-bit unsigned (unsigned char)
   S         | Integer | 16-bit unsigned, native endian (uint16_t)
   L         | Integer | 32-bit unsigned, native endian (uint32_t)
   Q         | Integer | 64-bit unsigned, native endian (uint64_t)
             |         |
   c         | Integer | 8-bit signed (signed char)
   s         | Integer | 16-bit signed, native endian (int16_t)
   l         | Integer | 32-bit signed, native endian (int32_t)
   q         | Integer | 64-bit signed, native endian (int64_t)
             |         |
   S_, S!    | Integer | unsigned short, native endian
   I, I_, I! | Integer | unsigned int, native endian
   L_, L!    | Integer | unsigned long, native endian
   Q_, Q!    | Integer | unsigned long long, native endian (ArgumentError
             |         | if the platform has no long long type.)
             |         | (Q_ and Q! is available since Ruby 2.1.)
             |         |
   s_, s!    | Integer | signed short, native endian
   i, i_, i! | Integer | signed int, native endian
   l_, l!    | Integer | signed long, native endian
   q_, q!    | Integer | signed long long, native endian (ArgumentError
             |         | if the platform has no long long type.)
             |         | (q_ and q! is available since Ruby 2.1.)
             |         |
   S> L> Q>  | Integer | same as the directives without ">" except
   s> l> q>  |         | big endian
   S!> I!>   |         | (available since Ruby 1.9.3)
   L!> Q!>   |         | "S>" is same as "n"
   s!> i!>   |         | "L>" is same as "N"
   l!> q!>   |         |
             |         |
   S< L< Q<  | Integer | same as the directives without "<" except
   s< l< q<  |         | little endian
   S!< I!<   |         | (available since Ruby 1.9.3)
   L!< Q!<   |         | "S<" is same as "v"
   s!< i!<   |         | "L<" is same as "V"
   l!< q!<   |         |
             |         |
   n         | Integer | 16-bit unsigned, network (big-endian) byte order
   N         | Integer | 32-bit unsigned, network (big-endian) byte order
   v         | Integer | 16-bit unsigned, VAX (little-endian) byte order
   V         | Integer | 32-bit unsigned, VAX (little-endian) byte order
             |         |
   U         | Integer | UTF-8 character
   w         | Integer | BER-compressed integer

Float        |         |
Directive    |         | Meaning
---------------------------------------------------------------------------
   D, d      | Float   | double-precision, native format
   F, f      | Float   | single-precision, native format
   E         | Float   | double-precision, little-endian byte order
   e         | Float   | single-precision, little-endian byte order
   G         | Float   | double-precision, network (big-endian) byte order
   g         | Float   | single-precision, network (big-endian) byte order

String       |         |
Directive    |         | Meaning
---------------------------------------------------------------------------
   A         | String  | arbitrary binary string (space padded, count is width)
   a         | String  | arbitrary binary string (null padded, count is width)
   Z         | String  | same as ``a'', except that null is added with *
   B         | String  | bit string (MSB first)
   b         | String  | bit string (LSB first)
   H         | String  | hex string (high nibble first)
   h         | String  | hex string (low nibble first)
   u         | String  | UU-encoded string
   M         | String  | quoted printable, MIME encoding (see RFC2045)
   m         | String  | base64 encoded string (see RFC 2045, count is width)
             |         | (if count is 0, no line feed are added, see RFC 4648)
   P         | String  | pointer to a structure (fixed-length string)
   p         | String  | pointer to a null-terminated string

Misc.        |         |
Directive    |         | Meaning
---------------------------------------------------------------------------
   @         | ---     | moves to absolute position
   X         | ---     | back up a byte
   x         | ---     | null byte



344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
 
# File 'pack.c', line 344

static VALUE
pack_pack(VALUE ary, VALUE fmt)
{
    static const char nul10[] = "\0\0\0\0\0\0\0\0\0\0";
    static const char spc10[] = "          ";
    const char *p, *pend;
    VALUE res, from, associates = 0;
    char type;
    long items, len, idx, plen;
    const char *ptr;
    int enc_info = 1;		/* 0 - BINARY, 1 - US-ASCII, 2 - UTF-8 */
#ifdef NATINT_PACK
    int natint;		/* native integer */
#endif
    int integer_size, bigendian_p;

    StringValue(fmt);
    p = RSTRING_PTR(fmt);
    pend = p + RSTRING_LEN(fmt);
    res = rb_str_buf_new(0);

    items = RARRAY_LEN(ary);
    idx = 0;

#define TOO_FEW (rb_raise(rb_eArgError, toofew), 0)
#define THISFROM (items > 0 ? RARRAY_AREF(ary, idx) : TOO_FEW)
#define NEXTFROM (items-- > 0 ? RARRAY_AREF(ary, idx++) : TOO_FEW)

    while (p < pend) {
	int explicit_endian = 0;
	if (RSTRING_PTR(fmt) + RSTRING_LEN(fmt) != pend) {
	    rb_raise(rb_eRuntimeError, "format string modified");
	}
	type = *p++;		/* get data type */
#ifdef NATINT_PACK
	natint = 0;
#endif

	if (ISSPACE(type)) continue;
	if (type == '#') {
	    while ((p < pend) && (*p != '\n')) {
		p++;
	    }
	    continue;
	}

	{
          modifiers:
	    switch (*p) {
	      case '_':
	      case '!':
		if (strchr(natstr, type)) {
#ifdef NATINT_PACK
		    natint = 1;
#endif
		    p++;
		}
		else {
		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, natstr);
		}
		goto modifiers;

	      case '<':
	      case '>':
		if (!strchr(endstr, type)) {
		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, endstr);
		}
		if (explicit_endian) {
		    rb_raise(rb_eRangeError, "Can't use both '<' and '>'");
		}
		explicit_endian = *p++;
		goto modifiers;
	    }
	}

	if (*p == '*') {	/* set data length */
	    len = strchr("@Xxu", type) ? 0
                : strchr("PMm", type) ? 1
                : items;
	    p++;
	}
	else if (ISDIGIT(*p)) {
	    errno = 0;
	    len = STRTOUL(p, (char**)&p, 10);
	    if (errno) {
		rb_raise(rb_eRangeError, "pack length too big");
	    }
	}
	else {
	    len = 1;
	}

	switch (type) {
	  case 'U':
	    /* if encoding is US-ASCII, upgrade to UTF-8 */
	    if (enc_info == 1) enc_info = 2;
	    break;
	  case 'm': case 'M': case 'u':
	    /* keep US-ASCII (do nothing) */
	    break;
	  default:
	    /* fall back to BINARY */
	    enc_info = 0;
	    break;
	}
	switch (type) {
	  case 'A': case 'a': case 'Z':
	  case 'B': case 'b':
	  case 'H': case 'h':
	    from = NEXTFROM;
	    if (NIL_P(from)) {
		ptr = "";
		plen = 0;
	    }
	    else {
		StringValue(from);
		ptr = RSTRING_PTR(from);
		plen = RSTRING_LEN(from);
		OBJ_INFECT(res, from);
	    }

	    if (p[-1] == '*')
		len = plen;

	    switch (type) {
	      case 'a':		/* arbitrary binary string (null padded)  */
	      case 'A':         /* arbitrary binary string (ASCII space padded) */
	      case 'Z':         /* null terminated string  */
		if (plen >= len) {
		    rb_str_buf_cat(res, ptr, len);
		    if (p[-1] == '*' && type == 'Z')
			rb_str_buf_cat(res, nul10, 1);
		}
		else {
		    rb_str_buf_cat(res, ptr, plen);
		    len -= plen;
		    while (len >= 10) {
			rb_str_buf_cat(res, (type == 'A')?spc10:nul10, 10);
			len -= 10;
		    }
		    rb_str_buf_cat(res, (type == 'A')?spc10:nul10, len);
		}
		break;

#define castchar(from) (char)((from) & 0xff)

	      case 'b':		/* bit string (ascending) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len - plen + 1)/2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			if (*ptr & 1)
			    byte |= 128;
			if (i & 7)
			    byte >>= 1;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 7) {
			char c;
			byte >>= 7 - (len & 7);
			c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;

	      case 'B':		/* bit string (descending) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len - plen + 1)/2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			byte |= *ptr & 1;
			if (i & 7)
			    byte <<= 1;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 7) {
			char c;
			byte <<= 7 - (len & 7);
			c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;

	      case 'h':		/* hex string (low nibble first) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len + 1) / 2 - (plen + 1) / 2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			if (ISALPHA(*ptr))
			    byte |= (((*ptr & 15) + 9) & 15) << 4;
			else
			    byte |= (*ptr & 15) << 4;
			if (i & 1)
			    byte >>= 4;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 1) {
			char c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;

	      case 'H':		/* hex string (high nibble first) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len + 1) / 2 - (plen + 1) / 2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			if (ISALPHA(*ptr))
			    byte |= ((*ptr & 15) + 9) & 15;
			else
			    byte |= *ptr & 15;
			if (i & 1)
			    byte <<= 4;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 1) {
			char c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;
	    }
	    break;

	  case 'c':		/* signed char */
	  case 'C':		/* unsigned char */
            integer_size = 1;
            bigendian_p = BIGENDIAN_P(); /* not effective */
            goto pack_integer;

	  case 's':		/* s for int16_t, s! for signed short */
            integer_size = NATINT_LEN(short, 2);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'S':		/* S for uint16_t, S! for unsigned short */
            integer_size = NATINT_LEN(short, 2);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'i':		/* i and i! for signed int */
            integer_size = (int)sizeof(int);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'I':		/* I and I! for unsigned int */
            integer_size = (int)sizeof(int);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'l':		/* l for int32_t, l! for signed long */
            integer_size = NATINT_LEN(long, 4);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'L':		/* L for uint32_t, L! for unsigned long */
            integer_size = NATINT_LEN(long, 4);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'q':		/* q for int64_t, q! for signed long long */
	    integer_size = NATINT_LEN_Q;
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'Q':		/* Q for uint64_t, Q! for unsigned long long */
	    integer_size = NATINT_LEN_Q;
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'n':		/* 16 bit (2 bytes) integer (network byte-order)  */
            integer_size = 2;
            bigendian_p = 1;
            goto pack_integer;

	  case 'N':		/* 32 bit (4 bytes) integer (network byte-order) */
            integer_size = 4;
            bigendian_p = 1;
            goto pack_integer;

	  case 'v':		/* 16 bit (2 bytes) integer (VAX byte-order) */
            integer_size = 2;
            bigendian_p = 0;
            goto pack_integer;

	  case 'V':		/* 32 bit (4 bytes) integer (VAX byte-order) */
            integer_size = 4;
            bigendian_p = 0;
            goto pack_integer;

          pack_integer:
	    if (explicit_endian) {
		bigendian_p = explicit_endian == '>';
	    }
            if (integer_size > MAX_INTEGER_PACK_SIZE)
                rb_bug("unexpected intger size for pack: %d", integer_size);
            while (len-- > 0) {
                char intbuf[MAX_INTEGER_PACK_SIZE];

                from = NEXTFROM;
                rb_integer_pack(from, intbuf, integer_size, 1, 0,
                    INTEGER_PACK_2COMP |
                    (bigendian_p ? INTEGER_PACK_BIG_ENDIAN : INTEGER_PACK_LITTLE_ENDIAN));
                rb_str_buf_cat(res, intbuf, integer_size);
            }
	    break;

	  case 'f':		/* single precision float in native format */
	  case 'F':		/* ditto */
	    while (len-- > 0) {
		float f;

		from = NEXTFROM;
		f = (float)RFLOAT_VALUE(rb_to_float(from));
		rb_str_buf_cat(res, (char*)&f, sizeof(float));
	    }
	    break;

	  case 'e':		/* single precision float in VAX byte-order */
	    while (len-- > 0) {
		float f;
		FLOAT_CONVWITH(ftmp);

		from = NEXTFROM;
		f = (float)RFLOAT_VALUE(rb_to_float(from));
		f = HTOVF(f,ftmp);
		rb_str_buf_cat(res, (char*)&f, sizeof(float));
	    }
	    break;

	  case 'E':		/* double precision float in VAX byte-order */
	    while (len-- > 0) {
		double d;
		DOUBLE_CONVWITH(dtmp);

		from = NEXTFROM;
		d = RFLOAT_VALUE(rb_to_float(from));
		d = HTOVD(d,dtmp);
		rb_str_buf_cat(res, (char*)&d, sizeof(double));
	    }
	    break;

	  case 'd':		/* double precision float in native format */
	  case 'D':		/* ditto */
	    while (len-- > 0) {
		double d;

		from = NEXTFROM;
		d = RFLOAT_VALUE(rb_to_float(from));
		rb_str_buf_cat(res, (char*)&d, sizeof(double));
	    }
	    break;

	  case 'g':		/* single precision float in network byte-order */
	    while (len-- > 0) {
		float f;
		FLOAT_CONVWITH(ftmp);

		from = NEXTFROM;
		f = (float)RFLOAT_VALUE(rb_to_float(from));
		f = HTONF(f,ftmp);
		rb_str_buf_cat(res, (char*)&f, sizeof(float));
	    }
	    break;

	  case 'G':		/* double precision float in network byte-order */
	    while (len-- > 0) {
		double d;
		DOUBLE_CONVWITH(dtmp);

		from = NEXTFROM;
		d = RFLOAT_VALUE(rb_to_float(from));
		d = HTOND(d,dtmp);
		rb_str_buf_cat(res, (char*)&d, sizeof(double));
	    }
	    break;

	  case 'x':		/* null byte */
	  grow:
	    while (len >= 10) {
		rb_str_buf_cat(res, nul10, 10);
		len -= 10;
	    }
	    rb_str_buf_cat(res, nul10, len);
	    break;

	  case 'X':		/* back up byte */
	  shrink:
	    plen = RSTRING_LEN(res);
	    if (plen < len)
		rb_raise(rb_eArgError, "X outside of string");
	    rb_str_set_len(res, plen - len);
	    break;

	  case '@':		/* null fill to absolute position */
	    len -= RSTRING_LEN(res);
	    if (len > 0) goto grow;
	    len = -len;
	    if (len > 0) goto shrink;
	    break;

	  case '%':
	    rb_raise(rb_eArgError, "%% is not supported");
	    break;

	  case 'U':		/* Unicode character */
	    while (len-- > 0) {
		SIGNED_VALUE l;
		char buf[8];
		int le;

		from = NEXTFROM;
		from = rb_to_int(from);
		l = NUM2LONG(from);
		if (l < 0) {
		    rb_raise(rb_eRangeError, "pack(U): value out of range");
		}
		le = rb_uv_to_utf8(buf, l);
		rb_str_buf_cat(res, (char*)buf, le);
	    }
	    break;

	  case 'u':		/* uuencoded string */
	  case 'm':		/* base64 encoded string */
	    from = NEXTFROM;
	    StringValue(from);
	    ptr = RSTRING_PTR(from);
	    plen = RSTRING_LEN(from);

	    if (len == 0 && type == 'm') {
		encodes(res, ptr, plen, type, 0);
		ptr += plen;
		break;
	    }
	    if (len <= 2)
		len = 45;
	    else if (len > 63 && type == 'u')
		len = 63;
	    else
		len = len / 3 * 3;
	    while (plen > 0) {
		long todo;

		if (plen > len)
		    todo = len;
		else
		    todo = plen;
		encodes(res, ptr, todo, type, 1);
		plen -= todo;
		ptr += todo;
	    }
	    break;

	  case 'M':		/* quoted-printable encoded string */
	    from = rb_obj_as_string(NEXTFROM);
	    if (len <= 1)
		len = 72;
	    qpencode(res, from, len);
	    break;

	  case 'P':		/* pointer to packed byte string */
	    from = THISFROM;
	    if (!NIL_P(from)) {
		StringValue(from);
		if (RSTRING_LEN(from) < len) {
		    rb_raise(rb_eArgError, "too short buffer for P(%ld for %ld)",
			     RSTRING_LEN(from), len);
		}
	    }
	    len = 1;
	    /* FALL THROUGH */
	  case 'p':		/* pointer to string */
	    while (len-- > 0) {
		char *t;
		from = NEXTFROM;
		if (NIL_P(from)) {
		    t = 0;
		}
		else {
		    t = StringValuePtr(from);
		    rb_obj_taint(from);
		}
		if (!associates) {
		    associates = rb_ary_new();
		}
		rb_ary_push(associates, from);
		rb_str_buf_cat(res, (char*)&t, sizeof(char*));
	    }
	    break;

	  case 'w':		/* BER compressed integer  */
	    while (len-- > 0) {
		VALUE buf = rb_str_new(0, 0);
                size_t numbytes;
                int sign;
                char *cp;

		from = NEXTFROM;
                from = rb_to_int(from);
                numbytes = rb_absint_numwords(from, 7, NULL);
                if (numbytes == 0)
                    numbytes = 1;
                buf = rb_str_new(NULL, numbytes);

                sign = rb_integer_pack(from, RSTRING_PTR(buf), RSTRING_LEN(buf), 1, 1, INTEGER_PACK_BIG_ENDIAN);

                if (sign < 0)
                    rb_raise(rb_eArgError, "can't compress negative numbers");
                if (sign == 2)
                    rb_bug("buffer size problem?");

                cp = RSTRING_PTR(buf);
                while (1 < numbytes) {
                  *cp |= 0x80;
                  cp++;
                  numbytes--;
                }

                rb_str_buf_cat(res, RSTRING_PTR(buf), RSTRING_LEN(buf));
	    }
	    break;

	  default: {
	    char unknown[5];
	    if (ISPRINT(type)) {
		unknown[0] = type;
		unknown[1] = '\0';
	    }
	    else {
		snprintf(unknown, sizeof(unknown), "\\x%.2x", type & 0xff);
	    }
	    rb_warning("unknown pack directive '%s' in '% "PRIsVALUE"'",
		       unknown, fmt);
	    break;
	  }
	}
    }

    if (associates) {
	str_associate(res, associates);
    }
    OBJ_INFECT(res, fmt);
    switch (enc_info) {
      case 1:
	ENCODING_CODERANGE_SET(res, rb_usascii_encindex(), ENC_CODERANGE_7BIT);
	break;
      case 2:
	rb_enc_set_index(res, rb_utf8_encindex());
	break;
      default:
	/* do nothing, keep ASCII-8BIT */
	break;
    }
    return res;
}

#permutation {|p| ... } ⇒ Object #permutation ⇒ Enumerator #permutation(n) {|p| ... } ⇒ Object #permutation(n) ⇒ Enumerator

When invoked with a block, yield all permutations of length n of the elements of the array, then return the array itself.

If n is not specified, yield all permutations of all elements.

The implementation makes no guarantees about the order in which the permutations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3]
a.permutation.to_a    #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
a.permutation(1).to_a #=> [[1],[2],[3]]
a.permutation(2).to_a #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]]
a.permutation(3).to_a #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
a.permutation(0).to_a #=> [[]] # one permutation of length 0
a.permutation(4).to_a #=> []   # no permutations of length 4

Overloads:



4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
 
# File 'array.c', line 4869

static VALUE
rb_ary_permutation(int argc, VALUE *argv, VALUE ary)
{
    VALUE num;
    long r, n, i;

    n = RARRAY_LEN(ary);                  /* Array length */
    RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_permutation_size);   /* Return enumerator if no block */
    rb_scan_args(argc, argv, "01", &num);
    r = NIL_P(num) ? n : NUM2LONG(num);   /* Permutation size from argument */

    if (r < 0 || n < r) {
	/* no permutations: yield nothing */
    }
    else if (r == 0) { /* exactly one permutation: the zero-length array */
	rb_yield(rb_ary_new2(0));
    }
    else if (r == 1) { /* this is a special, easy case */
	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else {             /* this is the general case */
	volatile VALUE t0;
	long *p = (long*)ALLOCV(t0, r*sizeof(long)+n*sizeof(char));
	char *used = (char*)(p + r);
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	RBASIC_CLEAR_CLASS(ary0);

	MEMZERO(used, char, n); /* initialize array */

	permute0(n, r, p, used, ary0); /* compute and yield permutations */
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#pop ⇒ Object? #pop(n) ⇒ Object

Removes the last element from self and returns it, or nil if the array is empty.

If a number n is given, returns an array of the last n elements (or less) just like array.slice!(-n, n) does. See also Array#push for the opposite effect.

a = [ "a", "b", "c", "d" ]
a.pop     #=> "d"
a.pop(2)  #=> ["b", "c"]
a         #=> ["a"]

Overloads:



985
986
987
988
989
990
991
992
993
994
995
996
997
998
 
# File 'array.c', line 985

static VALUE
rb_ary_pop_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE result;

    if (argc == 0) {
	return rb_ary_pop(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
    ARY_INCREASE_LEN(ary, -RARRAY_LEN(result));
    return result;
}

#product(other_ary, ...) ⇒ Object #product(other_ary, ...) {|p| ... } ⇒ Object

Returns an array of all combinations of elements from all arrays.

The length of the returned array is the product of the length of self and the argument arrays.

If given a block, #product will yield all combinations and return self instead.

[1,2,3].product([4,5])     #=> [[1,4],[1,5],[2,4],[2,5],[3,4],[3,5]]
[1,2].product([1,2])       #=> [[1,1],[1,2],[2,1],[2,2]]
[1,2].product([3,4],[5,6]) #=> [[1,3,5],[1,3,6],[1,4,5],[1,4,6],
                           #     [2,3,5],[2,3,6],[2,4,5],[2,4,6]]
[1,2].product()            #=> [[1],[2]]
[1,2].product([])          #=> []

Overloads:

  • #product(other_ary, ...) {|p| ... } ⇒ Object

    Yields:

    • (p) 


5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
 
# File 'array.c', line 5217

static VALUE
rb_ary_product(int argc, VALUE *argv, VALUE ary)
{
    int n = argc+1;    /* How many arrays we're operating on */
    volatile VALUE t0 = tmpary(n);
    volatile VALUE t1 = tmpbuf(n, sizeof(int));
    VALUE *arrays = RARRAY_PTR(t0); /* The arrays we're computing the product of */
    int *counters = (int*)RSTRING_PTR(t1); /* The current position in each one */
    VALUE result = Qnil;      /* The array we'll be returning, when no block given */
    long i,j;
    long resultlen = 1;

    RBASIC_CLEAR_CLASS(t0);
    RBASIC_CLEAR_CLASS(t1);

    /* initialize the arrays of arrays */
    ARY_SET_LEN(t0, n);
    arrays[0] = ary;
    for (i = 1; i < n; i++) arrays[i] = Qnil;
    for (i = 1; i < n; i++) arrays[i] = to_ary(argv[i-1]);

    /* initialize the counters for the arrays */
    for (i = 0; i < n; i++) counters[i] = 0;

    /* Otherwise, allocate and fill in an array of results */
    if (rb_block_given_p()) {
	/* Make defensive copies of arrays; exit if any is empty */
	for (i = 0; i < n; i++) {
	    if (RARRAY_LEN(arrays[i]) == 0) goto done;
	    arrays[i] = ary_make_shared_copy(arrays[i]);
	}
    }
    else {
	/* Compute the length of the result array; return [] if any is empty */
	for (i = 0; i < n; i++) {
	    long k = RARRAY_LEN(arrays[i]);
	    if (k == 0) {
		result = rb_ary_new2(0);
		goto done;
	    }
            if (MUL_OVERFLOW_LONG_P(resultlen, k))
		rb_raise(rb_eRangeError, "too big to product");
	    resultlen *= k;
	}
	result = rb_ary_new2(resultlen);
    }
    for (;;) {
	int m;
	/* fill in one subarray */
	VALUE subarray = rb_ary_new2(n);
	for (j = 0; j < n; j++) {
	    rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
	}

	/* put it on the result array */
	if (NIL_P(result)) {
	    FL_SET(t0, FL_USER5);
	    rb_yield(subarray);
	    if (! FL_TEST(t0, FL_USER5)) {
		rb_raise(rb_eRuntimeError, "product reentered");
	    }
	    else {
		FL_UNSET(t0, FL_USER5);
	    }
	}
	else {
	    rb_ary_push(result, subarray);
	}

	/*
	 * Increment the last counter.  If it overflows, reset to 0
	 * and increment the one before it.
	 */
	m = n-1;
	counters[m]++;
	while (counters[m] == RARRAY_LEN(arrays[m])) {
	    counters[m] = 0;
	    /* If the first counter overflows, we are done */
	    if (--m < 0) goto done;
	    counters[m]++;
	}
    }
done:
    tmpary_discard(t0);
    tmpbuf_discard(t1);

    return NIL_P(result) ? ary : result;
}

#push(obj, ...) ⇒ Object

Append — Pushes the given object(s) on to the end of this array. This expression returns the array itself, so several appends may be chained together. See also Array#pop for the opposite effect.

a = [ "a", "b", "c" ]
a.push("d", "e", "f")
        #=> ["a", "b", "c", "d", "e", "f"]
[1, 2, 3,].push(4).push(5)
        #=> [1, 2, 3, 4, 5]



943
944
945
946
947
 
# File 'array.c', line 943

static VALUE
rb_ary_push_m(int argc, VALUE *argv, VALUE ary)
{
    return rb_ary_cat(ary, argv, argc);
}

#rassoc(obj) ⇒ nil

Searches through the array whose elements are also arrays.

Compares obj with the second element of each contained array using obj.==.

Returns the first contained array that matches obj.

See also Array#assoc.

a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
a.rassoc("two")    #=> [2, "two"]
a.rassoc("four")   #=> nil

Returns:

  • (nil) 


3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
 
# File 'array.c', line 3698

VALUE
rb_ary_rassoc(VALUE ary, VALUE value)
{
    long i;
    VALUE v;

    for (i = 0; i < RARRAY_LEN(ary); ++i) {
	v = RARRAY_AREF(ary, i);
	if (RB_TYPE_P(v, T_ARRAY) &&
	    RARRAY_LEN(v) > 1 &&
	    rb_equal(RARRAY_AREF(v, 1), value))
	    return v;
    }
    return Qnil;
}

#reject {|item| ... } ⇒ Object #reject ⇒ Enumerator

Returns a new array containing the items in self for which the given block is not true.

See also Array#delete_if

If no block is given, an Enumerator is returned instead.

Overloads:



3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
 
# File 'array.c', line 3153

static VALUE
rb_ary_reject(VALUE ary)
{
    VALUE rejected_ary;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rejected_ary = rb_ary_new();
    ary_reject(ary, rejected_ary);
    return rejected_ary;
}

#reject! {|item| ... } ⇒ nil #reject! ⇒ Enumerator

Equivalent to Array#delete_if, deleting elements from self for which the block evaluates to true, but returns nil if no changes were made.

The array is changed instantly every time the block is called, not after the iteration is over.

See also Enumerable#reject and Array#delete_if.

If no block is given, an Enumerator is returned instead.

Overloads:

  • #reject! {|item| ... } ⇒ nil

    Yields:

    • (item)

    Returns:

    • (nil)
  • #reject! ⇒ Enumerator

    Returns:



3133
3134
3135
3136
3137
3138
 
# File 'array.c', line 3133

static VALUE
rb_ary_reject_bang(VALUE ary)
{
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    return ary_reject_bang(ary);
}

#repeated_combination(n) {|c| ... } ⇒ Object #repeated_combination(n) ⇒ Enumerator

When invoked with a block, yields all repeated combinations of length n of elements from the array and then returns the array itself.

The implementation makes no guarantees about the order in which the repeated combinations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3]
a.repeated_combination(1).to_a  #=> [[1], [2], [3]]
a.repeated_combination(2).to_a  #=> [[1,1],[1,2],[1,3],[2,2],[2,3],[3,3]]
a.repeated_combination(3).to_a  #=> [[1,1,1],[1,1,2],[1,1,3],[1,2,2],[1,2,3],
                                #    [1,3,3],[2,2,2],[2,2,3],[2,3,3],[3,3,3]]
a.repeated_combination(4).to_a  #=> [[1,1,1,1],[1,1,1,2],[1,1,1,3],[1,1,2,2],[1,1,2,3],
                                #    [1,1,3,3],[1,2,2,2],[1,2,2,3],[1,2,3,3],[1,3,3,3],
                                #    [2,2,2,2],[2,2,2,3],[2,2,3,3],[2,3,3,3],[3,3,3,3]]
a.repeated_combination(0).to_a  #=> [[]] # one combination of length 0

Overloads:



5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
 
# File 'array.c', line 5161

static VALUE
rb_ary_repeated_combination(VALUE ary, VALUE num)
{
    long n, i, len;

    n = NUM2LONG(num);                 /* Combination size from argument */
    RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_combination_size);   /* Return enumerator if no block */
    len = RARRAY_LEN(ary);
    if (n < 0) {
	/* yield nothing */
    }
    else if (n == 0) {
	rb_yield(rb_ary_new2(0));
    }
    else if (n == 1) {
	for (i = 0; i < len; i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else if (len == 0) {
	/* yield nothing */
    }
    else {
	volatile VALUE t0;
	long *p = ALLOCV_N(long, t0, n);
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	RBASIC_CLEAR_CLASS(ary0);

	rcombinate0(len, n, p, n, ary0); /* compute and yield repeated combinations */
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#repeated_permutation(n) {|p| ... } ⇒ Object #repeated_permutation(n) ⇒ Enumerator

When invoked with a block, yield all repeated permutations of length n of the elements of the array, then return the array itself.

The implementation makes no guarantees about the order in which the repeated permutations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2]
a.repeated_permutation(1).to_a  #=> [[1], [2]]
a.repeated_permutation(2).to_a  #=> [[1,1],[1,2],[2,1],[2,2]]
a.repeated_permutation(3).to_a  #=> [[1,1,1],[1,1,2],[1,2,1],[1,2,2],
                                #    [2,1,1],[2,1,2],[2,2,1],[2,2,2]]
a.repeated_permutation(0).to_a  #=> [[]] # one permutation of length 0

Overloads:



5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
 
# File 'array.c', line 5067

static VALUE
rb_ary_repeated_permutation(VALUE ary, VALUE num)
{
    long r, n, i;

    n = RARRAY_LEN(ary);                  /* Array length */
    RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_permutation_size);      /* Return Enumerator if no block */
    r = NUM2LONG(num);                    /* Permutation size from argument */

    if (r < 0) {
	/* no permutations: yield nothing */
    }
    else if (r == 0) { /* exactly one permutation: the zero-length array */
	rb_yield(rb_ary_new2(0));
    }
    else if (r == 1) { /* this is a special, easy case */
	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else {             /* this is the general case */
	volatile VALUE t0;
	long *p = ALLOCV_N(long, t0, r * sizeof(long));
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	RBASIC_CLEAR_CLASS(ary0);

	rpermute0(n, r, p, ary0); /* compute and yield repeated permutations */
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#replace(other_ary) ⇒ Object #initialize_copy(other_ary) ⇒ Object

Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]



3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
 
# File 'array.c', line 3352

VALUE
rb_ary_replace(VALUE copy, VALUE orig)
{
    rb_ary_modify_check(copy);
    orig = to_ary(orig);
    if (copy == orig) return copy;

    if (RARRAY_LEN(orig) <= RARRAY_EMBED_LEN_MAX) {
        VALUE shared = 0;

        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
	}
        else if (ARY_SHARED_P(copy)) {
            shared = ARY_SHARED(copy);
            FL_UNSET_SHARED(copy);
        }
        FL_SET_EMBED(copy);
	ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR(orig));
        if (shared) {
            rb_ary_decrement_share(shared);
        }
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
    }
    else {
        VALUE shared = ary_make_shared(orig);
        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
        }
        else {
            rb_ary_unshare_safe(copy);
        }
        FL_UNSET_EMBED(copy);
        ARY_SET_PTR(copy, RARRAY_CONST_PTR(orig));
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
        rb_ary_set_shared(copy, shared);
    }
    return copy;
}

#reverse ⇒ Object

Returns a new array containing self‘s elements in reverse order.

[ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
[ 1 ].reverse               #=> [1]



2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
 
# File 'array.c', line 2236

static VALUE
rb_ary_reverse_m(VALUE ary)
{
    long len = RARRAY_LEN(ary);
    VALUE dup = rb_ary_new2(len);

    if (len > 0) {
	const VALUE *p1 = RARRAY_CONST_PTR(ary);
	VALUE *p2 = (VALUE *)RARRAY_CONST_PTR(dup) + len - 1;
	do *p2-- = *p1++; while (--len > 0);
    }
    ARY_SET_LEN(dup, RARRAY_LEN(ary));
    return dup;
}

#reverse! ⇒ Object

Reverses self in place.

a = [ "a", "b", "c" ]
a.reverse!       #=> ["c", "b", "a"]
a                #=> ["c", "b", "a"]



2220
2221
2222
2223
2224
 
# File 'array.c', line 2220

static VALUE
rb_ary_reverse_bang(VALUE ary)
{
    return rb_ary_reverse(ary);
}

#reverse_each {|item| ... } ⇒ Object #reverse_each ⇒ Enumerator

Same as Array#each, but traverses self in reverse order.

a = [ "a", "b", "c" ]
a.reverse_each {|x| print x, " " }

produces:

c b a

Overloads:



1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
 
# File 'array.c', line 1853

static VALUE
rb_ary_reverse_each(VALUE ary)
{
    long len;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    len = RARRAY_LEN(ary);
    while (len--) {
	long nlen;
	rb_yield(RARRAY_AREF(ary, len));
	nlen = RARRAY_LEN(ary);
	if (nlen < len) {
	    len = nlen;
	}
    }
    return ary;
}

#rindex(obj) ⇒ Integer? #rindex {|item| ... } ⇒ Integer? #rindex ⇒ Enumerator

Returns the index of the last object in self == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true, starting from the last object.

Returns nil if no match is found.

See also Array#index.

If neither block nor argument is given, an Enumerator is returned instead.

a = [ "a", "b", "b", "b", "c" ]
a.rindex("b")             #=> 3
a.rindex("z")             #=> nil
a.rindex { |x| x == "b" } #=> 3

Overloads:



1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
 
# File 'array.c', line 1495

static VALUE
rb_ary_rindex(int argc, VALUE *argv, VALUE ary)
{
    const VALUE *ptr;
    VALUE val;
    long i = RARRAY_LEN(ary), len;

    if (argc == 0) {
	RETURN_ENUMERATOR(ary, 0, 0);
	while (i--) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i))))
		return LONG2NUM(i);
	    if (i > (len = RARRAY_LEN(ary))) {
		i = len;
	    }
	}
	return Qnil;
    }
    rb_check_arity(argc, 0, 1);
    val = argv[0];
    if (rb_block_given_p())
	rb_warn("given block not used");
    ptr = RARRAY_CONST_PTR(ary);
    while (i--) {
	VALUE e = ptr[i];
	switch (rb_equal_opt(e, val)) {
	  case Qundef:
	    if (!rb_equal(e, val)) break;
	  case Qtrue:
	    return LONG2NUM(i);
	  case Qfalse:
	    continue;
	}
	if (i > (len = RARRAY_LEN(ary))) {
	    i = len;
	}
	ptr = RARRAY_CONST_PTR(ary);
    }
    return Qnil;
}

#rotate(count = 1) ⇒ Object

Returns a new array by rotating self so that the element at count is the first element of the new array.

If count is negative then it rotates in the opposite direction, starting from the end of self where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.rotate         #=> ["b", "c", "d", "a"]
a                #=> ["a", "b", "c", "d"]
a.rotate(2)      #=> ["c", "d", "a", "b"]
a.rotate(-3)     #=> ["b", "c", "d", "a"]



2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
 
# File 'array.c', line 2326

static VALUE
rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE rotated;
    const VALUE *ptr;
    long len, cnt = 1;

    switch (argc) {
      case 1: cnt = NUM2LONG(argv[0]);
      case 0: break;
      default: rb_scan_args(argc, argv, "01", NULL);
    }

    len = RARRAY_LEN(ary);
    rotated = rb_ary_new2(len);
    if (len > 0) {
	cnt = rotate_count(cnt, len);
	ptr = RARRAY_CONST_PTR(ary);
	len -= cnt;
	ary_memcpy(rotated, 0, len, ptr + cnt);
	ary_memcpy(rotated, len, cnt, ptr);
    }
    ARY_SET_LEN(rotated, RARRAY_LEN(ary));
    return rotated;
}

#rotate!(count = 1) ⇒ Object

Rotates self in place so that the element at count comes first, and returns self.

If count is negative then it rotates in the opposite direction, starting from the end of the array where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.rotate!        #=> ["b", "c", "d", "a"]
a                #=> ["b", "c", "d", "a"]
a.rotate!(2)     #=> ["d", "a", "b", "c"]
a.rotate!(-3)    #=> ["a", "b", "c", "d"]



2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
 
# File 'array.c', line 2295

static VALUE
rb_ary_rotate_bang(int argc, VALUE *argv, VALUE ary)
{
    long n = 1;

    switch (argc) {
      case 1: n = NUM2LONG(argv[0]);
      case 0: break;
      default: rb_scan_args(argc, argv, "01", NULL);
    }
    rb_ary_rotate(ary, n);
    return ary;
}

#sample ⇒ Object #sample(random: rng) ⇒ Object #sample(n) ⇒ Object #sample(n, random: rng) ⇒ Object

Choose a random element or n random elements from the array.

The elements are chosen by using random and unique indices into the array in order to ensure that an element doesn’t repeat itself unless the array already contained duplicate elements.

If the array is empty the first form returns nil and the second form returns an empty array.

The optional rng argument will be used as the random number generator.

a = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
a.sample         #=> 7
a.sample(4)      #=> [6, 4, 2, 5]

Overloads:



4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
 
# File 'array.c', line 4566

static VALUE
rb_ary_sample(int argc, VALUE *argv, VALUE ary)
{
    VALUE nv, result;
    VALUE opts, randgen = rb_cRandom;
    long n, len, i, j, k, idx[10];
    long rnds[numberof(idx)];

    if (OPTHASH_GIVEN_P(opts)) {
	VALUE rnd;
	ID keyword_ids[1];

	keyword_ids[0] = id_random;
	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
	if (rnd != Qundef) {
	    randgen = rnd;
	}
    }
    len = RARRAY_LEN(ary);
    if (argc == 0) {
	if (len < 2)
	    i = 0;
	else
	    i = RAND_UPTO(len);

	return rb_ary_elt(ary, i);
    }
    rb_scan_args(argc, argv, "1", &nv);
    n = NUM2LONG(nv);
    if (n < 0) rb_raise(rb_eArgError, "negative sample number");
    if (n > len) n = len;
    if (n <= numberof(idx)) {
	for (i = 0; i < n; ++i) {
	    rnds[i] = RAND_UPTO(len - i);
	}
    }
    k = len;
    len = RARRAY_LEN(ary);
    if (len < k && n <= numberof(idx)) {
	for (i = 0; i < n; ++i) {
	    if (rnds[i] >= len) return rb_ary_new_capa(0);
	}
    }
    if (n > len) n = len;
    switch (n) {
      case 0:
	return rb_ary_new_capa(0);
      case 1:
	i = rnds[0];
	return rb_ary_new_from_values(1, &RARRAY_AREF(ary, i));
      case 2:
	i = rnds[0];
	j = rnds[1];
	if (j >= i) j++;
	return rb_ary_new_from_args(2, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j));
      case 3:
	i = rnds[0];
	j = rnds[1];
	k = rnds[2];
	{
	    long l = j, g = i;
	    if (j >= i) l = i, g = ++j;
	    if (k >= l && (++k >= g)) ++k;
	}
	return rb_ary_new_from_args(3, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j), RARRAY_AREF(ary, k));
    }
    if (n <= numberof(idx)) {
	long sorted[numberof(idx)];
	sorted[0] = idx[0] = rnds[0];
	for (i=1; i<n; i++) {
	    k = rnds[i];
	    for (j = 0; j < i; ++j) {
		if (k < sorted[j]) break;
		++k;
	    }
	    memmove(&sorted[j+1], &sorted[j], sizeof(sorted[0])*(i-j));
	    sorted[j] = idx[i] = k;
	}
	result = rb_ary_new_capa(n);
	RARRAY_PTR_USE(result, ptr_result, {
	    for (i=0; i<n; i++) {
		ptr_result[i] = RARRAY_AREF(ary, idx[i]);
	    }
	});
    }
    else {
	result = rb_ary_dup(ary);
	RBASIC_CLEAR_CLASS(result);
	RB_GC_GUARD(ary);
	RARRAY_PTR_USE(result, ptr_result, {
	    for (i=0; i<n; i++) {
		j = RAND_UPTO(len-i) + i;
		nv = ptr_result[j];
		ptr_result[j] = ptr_result[i];
		ptr_result[i] = nv;
	    }
	});
	RBASIC_SET_CLASS_RAW(result, rb_cArray);
    }
    ARY_SET_LEN(result, n);

    return result;
}

#select {|item| ... } ⇒ Object #select ⇒ Enumerator

Returns a new array containing all elements of ary for which the given block returns a true value.

If no block is given, an Enumerator is returned instead.

[1,2,3,4,5].select { |num|  num.even?  }   #=> [2, 4]

a = %w{ a b c d e f }
a.select { |v| v =~ /[aeiou]/ }  #=> ["a", "e"]

See also Enumerable#select.

Overloads:



2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
 
# File 'array.c', line 2804

static VALUE
rb_ary_select(VALUE ary)
{
    VALUE result;
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    result = rb_ary_new2(RARRAY_LEN(ary));
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
	    rb_ary_push(result, rb_ary_elt(ary, i));
	}
    }
    return result;
}

#select! {|item| ... } ⇒ nil #select! ⇒ Enumerator

Invokes the given block passing in successive elements from self, deleting elements for which the block returns a false value.

If changes were made, it will return self, otherwise it returns nil.

See also Array#keep_if

If no block is given, an Enumerator is returned instead.

Overloads:

  • #select! {|item| ... } ⇒ nil

    Yields:

    • (item)

    Returns:

    • (nil)
  • #select! ⇒ Enumerator

    Returns:



2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
 
# File 'array.c', line 2836

static VALUE
rb_ary_select_bang(VALUE ary)
{
    long i1, i2;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
	VALUE v = RARRAY_AREF(ary, i1);
	if (!RTEST(rb_yield(v))) continue;
	if (i1 != i2) {
	    rb_ary_store(ary, i2, v);
	}
	i2++;
    }

    if (i1 == i2) return Qnil;
    if (i2 < i1)
	ARY_SET_LEN(ary, i2);
    return ary;
}

#shift ⇒ Object? #shift(n) ⇒ Object

Removes the first element of self and returns it (shifting all other elements down by one). Returns nil if the array is empty.

If a number n is given, returns an array of the first n elements (or less) just like array.slice!(0, n) does. With ary containing only the remainder elements, not including what was shifted to new_ary. See also Array#unshift for the opposite effect.

args = [ "-m", "-q", "filename" ]
args.shift     #=> "-m"
args           #=> ["-q", "filename"]

args = [ "-m", "-q", "filename" ]
args.shift(2)  #=> ["-m", "-q"]
args           #=> ["filename"]

Overloads:



1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
 
# File 'array.c', line 1054

static VALUE
rb_ary_shift_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE result;
    long n;

    if (argc == 0) {
	return rb_ary_shift(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
    n = RARRAY_LEN(result);
    if (ARY_SHARED_P(ary)) {
	if (ARY_SHARED_OCCUPIED(ARY_SHARED(ary))) {
	    ary_mem_clear(ary, 0, n);
	}
        ARY_INCREASE_PTR(ary, n);
    }
    else {
	RARRAY_PTR_USE(ary, ptr, {
	    MEMMOVE(ptr, ptr + n, VALUE, RARRAY_LEN(ary)-n);
	}); /* WB: no new reference */
    }
    ARY_INCREASE_LEN(ary, -n);

    return result;
}

#shuffle ⇒ Object #shuffle(random: rng) ⇒ Object

Returns a new array with elements of self shuffled.

a = [ 1, 2, 3 ]           #=> [1, 2, 3]
a.shuffle                 #=> [2, 3, 1]
a                         #=> [1, 2, 3]

The optional rng argument will be used as the random number generator.

a.shuffle(random: Random.new(1))  #=> [1, 3, 2]



4533
4534
4535
4536
4537
4538
4539
 
# File 'array.c', line 4533

static VALUE
rb_ary_shuffle(int argc, VALUE *argv, VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_shuffle_bang(argc, argv, ary);
    return ary;
}

#shuffle! ⇒ Object #shuffle!(random: rng) ⇒ Object

Shuffles elements in self in place.

a = [ 1, 2, 3 ]           #=> [1, 2, 3]
a.shuffle!                #=> [2, 3, 1]
a                         #=> [2, 3, 1]

The optional rng argument will be used as the random number generator.

a.shuffle!(random: Random.new(1))  #=> [1, 3, 2]



4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
 
# File 'array.c', line 4482

static VALUE
rb_ary_shuffle_bang(int argc, VALUE *argv, VALUE ary)
{
    VALUE opts, randgen = rb_cRandom;
    long i, len;

    if (OPTHASH_GIVEN_P(opts)) {
	VALUE rnd;
	ID keyword_ids[1];

	keyword_ids[0] = id_random;
	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
	if (rnd != Qundef) {
	    randgen = rnd;
	}
    }
    rb_check_arity(argc, 0, 0);
    rb_ary_modify(ary);
    i = len = RARRAY_LEN(ary);
    RARRAY_PTR_USE(ary, ptr, {
	while (i) {
	    long j = RAND_UPTO(i);
	    VALUE tmp;
	    if (len != RARRAY_LEN(ary) || ptr != RARRAY_CONST_PTR(ary)) {
		rb_raise(rb_eRuntimeError, "modified during shuffle");
	    }
	    tmp = ptr[--i];
	    ptr[i] = ptr[j];
	    ptr[j] = tmp;
	}
    }); /* WB: no new reference */
    return ary;
}

#[](index) ⇒ Object? #[](start, length) ⇒ nil #[](range) ⇒ nil #slice(index) ⇒ Object? #slice(start, length) ⇒ nil #slice(range) ⇒ nil

Element Reference — Returns the element at index, or returns a subarray starting at the start index and continuing for length elements, or returns a subarray specified by range of indices.

Negative indices count backward from the end of the array (-1 is the last element). For start and range cases the starting index is just before an element. Additionally, an empty array is returned when the starting index for an element range is at the end of the array.

Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[6, 1]                #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

Overloads:

  • #[](index) ⇒ Object?

    Returns:

  • #[](start, length) ⇒ nil

    Returns:

    • (nil)
  • #[](range) ⇒ nil

    Returns:

    • (nil)
  • #slice(index) ⇒ Object?

    Returns:

  • #slice(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice(range) ⇒ nil

    Returns:

    • (nil) 


1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
 
# File 'array.c', line 1248

VALUE
rb_ary_aref(int argc, const VALUE *argv, VALUE ary)
{
    VALUE arg;
    long beg, len;

    if (argc == 2) {
	beg = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
	if (beg < 0) {
	    beg += RARRAY_LEN(ary);
	}
	return rb_ary_subseq(ary, beg, len);
    }
    if (argc != 1) {
	rb_scan_args(argc, argv, "11", NULL, NULL);
    }
    arg = argv[0];
    /* special case - speeding up */
    if (FIXNUM_P(arg)) {
	return rb_ary_entry(ary, FIX2LONG(arg));
    }
    /* check if idx is Range */
    switch (rb_range_beg_len(arg, &beg, &len, RARRAY_LEN(ary), 0)) {
      case Qfalse:
	break;
      case Qnil:
	return Qnil;
      default:
	return rb_ary_subseq(ary, beg, len);
    }
    return rb_ary_entry(ary, NUM2LONG(arg));
}

#slice!(index) ⇒ Object? #slice!(start, length) ⇒ nil #slice!(range) ⇒ nil

Deletes the element(s) given by an index (optionally up to length elements) or by a range.

Returns the deleted object (or objects), or nil if the index is out of range.

a = [ "a", "b", "c" ]
a.slice!(1)     #=> "b"
a               #=> ["a", "c"]
a.slice!(-1)    #=> "c"
a               #=> ["a"]
a.slice!(100)   #=> nil
a               #=> ["a"]

Overloads:

  • #slice!(index) ⇒ Object?

    Returns:

  • #slice!(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice!(range) ⇒ nil

    Returns:

    • (nil) 


3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
 
# File 'array.c', line 3032

static VALUE
rb_ary_slice_bang(int argc, VALUE *argv, VALUE ary)
{
    VALUE arg1, arg2;
    long pos, len, orig_len;

    rb_ary_modify_check(ary);
    if (argc == 2) {
	pos = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
      delete_pos_len:
	if (len < 0) return Qnil;
	orig_len = RARRAY_LEN(ary);
	if (pos < 0) {
	    pos += orig_len;
	    if (pos < 0) return Qnil;
	}
	else if (orig_len < pos) return Qnil;
	if (orig_len < pos + len) {
	    len = orig_len - pos;
	}
	if (len == 0) return rb_ary_new2(0);
	arg2 = rb_ary_new4(len, RARRAY_CONST_PTR(ary)+pos);
	RBASIC_SET_CLASS(arg2, rb_obj_class(ary));
	rb_ary_splice(ary, pos, len, Qundef);
	return arg2;
    }

    if (argc != 1) {
	/* error report */
	rb_scan_args(argc, argv, "11", NULL, NULL);
    }
    arg1 = argv[0];

    if (!FIXNUM_P(arg1)) {
	switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
	  case Qtrue:
	    /* valid range */
	    goto delete_pos_len;
	  case Qnil:
	    /* invalid range */
	    return Qnil;
	  default:
	    /* not a range */
	    break;
	}
    }

    return rb_ary_delete_at(ary, NUM2LONG(arg1));
}

#sort ⇒ Object #sort {|a, b| ... } ⇒ Object

Returns a new array created by sorting self.

Comparisons for the sort will be done using the <=> operator or using an optional code block.

The block must implement a comparison between a and b, and return -1, when a follows b, 0 when a and b are equivalent, or +1 if b follows a.

See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort                    #=> ["a", "b", "c", "d", "e"]
a.sort { |x,y| y <=> x }  #=> ["e", "d", "c", "b", "a"]

Overloads:

  • #sort {|a, b| ... } ⇒ Object

    Yields:

    • (a, b) 


2524
2525
2526
2527
2528
2529
2530
 
# File 'array.c', line 2524

VALUE
rb_ary_sort(VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_sort_bang(ary);
    return ary;
}

#sort! ⇒ Object #sort! {|a, b| ... } ⇒ Object

Sorts self in place.

Comparisons for the sort will be done using the <=> operator or using an optional code block.

The block must implement a comparison between a and b, and return -1, when a follows b, 0 when a and b are equivalent, or +1 if b follows a.

See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort!                    #=> ["a", "b", "c", "d", "e"]
a.sort! { |x,y| y <=> x }  #=> ["e", "d", "c", "b", "a"]

Overloads:

  • #sort! {|a, b| ... } ⇒ Object

    Yields:

    • (a, b) 


2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
 
# File 'array.c', line 2442

VALUE
rb_ary_sort_bang(VALUE ary)
{
    rb_ary_modify(ary);
    assert(!ARY_SHARED_P(ary));
    if (RARRAY_LEN(ary) > 1) {
	VALUE tmp = ary_make_substitution(ary); /* only ary refers tmp */
	struct ary_sort_data data;
	long len = RARRAY_LEN(ary);

	RBASIC_CLEAR_CLASS(tmp);
	data.ary = tmp;
	data.opt_methods = 0;
	data.opt_inited = 0;
	RARRAY_PTR_USE(tmp, ptr, {
	    ruby_qsort(ptr, len, sizeof(VALUE),
		       rb_block_given_p()?sort_1:sort_2, &data);
	}); /* WB: no new reference */
	rb_ary_modify(ary);
        if (ARY_EMBED_P(tmp)) {
            if (ARY_SHARED_P(ary)) { /* ary might be destructively operated in the given block */
                rb_ary_unshare(ary);
            }
            FL_SET_EMBED(ary);
	    ary_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
            ARY_SET_LEN(ary, ARY_EMBED_LEN(tmp));
        }
        else {
            if (!ARY_EMBED_P(ary) && ARY_HEAP_PTR(ary) == ARY_HEAP_PTR(tmp)) {
                FL_UNSET_SHARED(ary);
                ARY_SET_CAPA(ary, RARRAY_LEN(tmp));
            }
            else {
                assert(!ARY_SHARED_P(tmp));
                if (ARY_EMBED_P(ary)) {
                    FL_UNSET_EMBED(ary);
                }
                else if (ARY_SHARED_P(ary)) {
                    /* ary might be destructively operated in the given block */
                    rb_ary_unshare(ary);
                }
                else {
		    ruby_sized_xfree((void *)ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
                }
                ARY_SET_PTR(ary, RARRAY_CONST_PTR(tmp));
                ARY_SET_HEAP_LEN(ary, len);
                ARY_SET_CAPA(ary, RARRAY_LEN(tmp));
            }
            /* tmp was lost ownership for the ptr */
            FL_UNSET(tmp, FL_FREEZE);
            FL_SET_EMBED(tmp);
            ARY_SET_EMBED_LEN(tmp, 0);
            FL_SET(tmp, FL_FREEZE);
	}
        /* tmp will be GC'ed. */
        RBASIC_SET_CLASS_RAW(tmp, rb_cArray); /* rb_cArray must be marked */
    }
    return ary;
}

#sort_by! {|obj| ... } ⇒ Object #sort_by! ⇒ Enumerator

Sorts self in place using a set of keys generated by mapping the values in self through the given block.

If no block is given, an Enumerator is returned instead.

Overloads:



2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
 
# File 'array.c', line 2652

static VALUE
rb_ary_sort_by_bang(VALUE ary)
{
    VALUE sorted;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    sorted = rb_block_call(ary, rb_intern("sort_by"), 0, 0, sort_by_i, 0);
    rb_ary_replace(ary, sorted);
    return ary;
}

#take(n) ⇒ Object

Returns first n elements from the array.

If a negative number is given, raises an ArgumentError.

See also Array#drop

a = [1, 2, 3, 4, 5, 0]
a.take(3)             #=> [1, 2, 3]



5321
5322
5323
5324
5325
5326
5327
5328
5329
 
# File 'array.c', line 5321

static VALUE
rb_ary_take(VALUE obj, VALUE n)
{
    long len = NUM2LONG(n);
    if (len < 0) {
	rb_raise(rb_eArgError, "attempt to take negative size");
    }
    return rb_ary_subseq(obj, 0, len);
}

#take_while {|arr| ... } ⇒ Object #take_while ⇒ Enumerator

Passes elements to the block until the block returns nil or false, then stops iterating and returns an array of all prior elements.

If no block is given, an Enumerator is returned instead.

See also Array#drop_while

a = [1, 2, 3, 4, 5, 0]
a.take_while { |i| i < 3 }  #=> [1, 2]

Overloads:



5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
 
# File 'array.c', line 5348

static VALUE
rb_ary_take_while(VALUE ary)
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
    }
    return rb_ary_take(ary, LONG2FIX(i));
}

#to_a ⇒ Object

Returns self.

If called on a subclass of Array, converts the receiver to an Array object.



2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
 
# File 'array.c', line 2128

static VALUE
rb_ary_to_a(VALUE ary)
{
    if (rb_obj_class(ary) != rb_cArray) {
	VALUE dup = rb_ary_new2(RARRAY_LEN(ary));
	rb_ary_replace(dup, ary);
	return dup;
    }
    return ary;
}

#to_ary ⇒ Object

Returns self.



2177
2178
2179
2180
2181
 
# File 'array.c', line 2177

static VALUE
rb_ary_to_ary_m(VALUE ary)
{
    return ary;
}

#to_h ⇒ Hash

Returns the result of interpreting ary as an array of [key, value] pairs.

[[:foo, :bar], [1, 2]].to_h
  # => {:foo => :bar, 1 => 2}

Returns:



2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
 
# File 'array.c', line 2150

static VALUE
rb_ary_to_h(VALUE ary)
{
    long i;
    VALUE hash = rb_hash_new();
    for (i=0; i<RARRAY_LEN(ary); i++) {
	VALUE key_value_pair = rb_check_array_type(rb_ary_elt(ary, i));
	if (NIL_P(key_value_pair)) {
	    rb_raise(rb_eTypeError, "wrong element type %s at %ld (expected array)",
		rb_builtin_class_name(rb_ary_elt(ary, i)), i);
	}
	if (RARRAY_LEN(key_value_pair) != 2) {
	    rb_raise(rb_eArgError, "wrong array length at %ld (expected 2, was %ld)",
		i, RARRAY_LEN(key_value_pair));
	}
	rb_hash_aset(hash, RARRAY_AREF(key_value_pair, 0), RARRAY_AREF(key_value_pair, 1));
    }
    return hash;
}

#transpose ⇒ Object

Assumes that self is an array of arrays and transposes the rows and columns.

a = [[1,2], [3,4], [5,6]]
a.transpose   #=> [[1, 3, 5], [2, 4, 6]]

If the length of the subarrays don’t match, an IndexError is raised.



3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
 
# File 'array.c', line 3311

static VALUE
rb_ary_transpose(VALUE ary)
{
    long elen = -1, alen, i, j;
    VALUE tmp, result = 0;

    alen = RARRAY_LEN(ary);
    if (alen == 0) return rb_ary_dup(ary);
    for (i=0; i<alen; i++) {
	tmp = to_ary(rb_ary_elt(ary, i));
	if (elen < 0) {		/* first element */
	    elen = RARRAY_LEN(tmp);
	    result = rb_ary_new2(elen);
	    for (j=0; j<elen; j++) {
		rb_ary_store(result, j, rb_ary_new2(alen));
	    }
	}
	else if (elen != RARRAY_LEN(tmp)) {
	    rb_raise(rb_eIndexError, "element size differs (%ld should be %ld)",
		     RARRAY_LEN(tmp), elen);
	}
	for (j=0; j<elen; j++) {
	    rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
	}
    }
    return result;
}

#uniq ⇒ Object #uniq {|item| ... } ⇒ Object

Returns a new array by removing duplicate values in self.

If a block is given, it will use the return value of the block for comparison.

It compares values using their #hash and #eql? methods for efficiency.

a = [ "a", "a", "b", "b", "c" ]
a.uniq   # => ["a", "b", "c"]

b = [["student","sam"], ["student","george"], ["teacher","matz"]]
b.uniq { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]

Overloads:

  • #uniq {|item| ... } ⇒ Object

    Yields:

    • (item) 


4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
 
# File 'array.c', line 4199

static VALUE
rb_ary_uniq(VALUE ary)
{
    VALUE hash, uniq;

    if (RARRAY_LEN(ary) <= 1)
        return rb_ary_dup(ary);
    if (rb_block_given_p()) {
	hash = ary_make_hash_by(ary);
	uniq = rb_hash_values(hash);
    }
    else {
	hash = ary_make_hash(ary);
	uniq = rb_hash_values(hash);
    }
    RBASIC_SET_CLASS(uniq, rb_obj_class(ary));
    ary_recycle_hash(hash);

    return uniq;
}

#uniq! ⇒ nil #uniq! {|item| ... } ⇒ nil

Removes duplicate elements from self.

If a block is given, it will use the return value of the block for comparison.

It compares values using their #hash and #eql? methods for efficiency.

Returns nil if no changes are made (that is, no duplicates are found).

a = [ "a", "a", "b", "b", "c" ]
a.uniq!   # => ["a", "b", "c"]

b = [ "a", "b", "c" ]
b.uniq!   # => nil

c = [["student","sam"], ["student","george"], ["teacher","matz"]]
c.uniq! { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]

Overloads:

  • #uniq! ⇒ nil

    Returns:

    • (nil)
  • #uniq! {|item| ... } ⇒ nil

    Yields:

    • (item)

    Returns:

    • (nil) 


4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
 
# File 'array.c', line 4149

static VALUE
rb_ary_uniq_bang(VALUE ary)
{
    VALUE hash;
    long hash_size;

    rb_ary_modify_check(ary);
    if (RARRAY_LEN(ary) <= 1)
        return Qnil;
    if (rb_block_given_p())
	hash = ary_make_hash_by(ary);
    else
	hash = ary_make_hash(ary);

    hash_size = RHASH_SIZE(hash);
    if (RARRAY_LEN(ary) == hash_size) {
	return Qnil;
    }
    rb_ary_modify_check(ary);
    ARY_SET_LEN(ary, 0);
    if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
	rb_ary_unshare(ary);
	FL_SET_EMBED(ary);
    }
    ary_resize_capa(ary, hash_size);
    st_foreach(rb_hash_tbl_raw(hash), push_value, ary);
    ary_recycle_hash(hash);

    return ary;
}

#unshift(obj, ...) ⇒ Object

Prepends objects to the front of self, moving other elements upwards. See also Array#shift for the opposite effect.

a = [ "b", "c", "d" ]
a.unshift("a")   #=> ["a", "b", "c", "d"]
a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]



1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
 
# File 'array.c', line 1150

static VALUE
rb_ary_unshift_m(int argc, VALUE *argv, VALUE ary)
{
    long len = RARRAY_LEN(ary);
    VALUE target_ary;

    if (argc == 0) {
	rb_ary_modify_check(ary);
	return ary;
    }

    target_ary = ary_ensure_room_for_unshift(ary, argc);
    ary_memcpy0(ary, 0, argc, argv, target_ary);
    ARY_SET_LEN(ary, len + argc);
    return ary;
}

#values_at(selector, ...) ⇒ Object

Returns an array containing the elements in self corresponding to the given selector(s).

The selectors may be either integer indices or ranges.

See also Array#select.

a = %w{ a b c d e f }
a.values_at(1, 3, 5)          # => ["b", "d", "f"]
a.values_at(1, 3, 5, 7)       # => ["b", "d", "f", nil]
a.values_at(-1, -2, -2, -7)   # => ["f", "e", "e", nil]
a.values_at(4..6, 3...6)      # => ["e", "f", nil, "d", "e", "f"]



2779
2780
2781
2782
2783
 
# File 'array.c', line 2779

static VALUE
rb_ary_values_at(int argc, VALUE *argv, VALUE ary)
{
    return rb_get_values_at(ary, RARRAY_LEN(ary), argc, argv, rb_ary_entry);
}

#zip(arg, ...) ⇒ Object #zip(arg, ...) {|arr| ... } ⇒ nil

Converts any arguments to arrays, then merges elements of self with corresponding elements from each argument.

This generates a sequence of ary.size n-element arrays, where n is one more than the count of arguments.

If the size of any argument is less than the size of the initial array, nil values are supplied.

If a block is given, it is invoked for each output array, otherwise an array of arrays is returned.

a = [ 4, 5, 6 ]
b = [ 7, 8, 9 ]
[1, 2, 3].zip(a, b)   #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
[1, 2].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8]]
a.zip([1, 2], [8])    #=> [[4, 1, 8], [5, 2, nil], [6, nil, nil]]

Overloads:

  • #zip(arg, ...) {|arr| ... } ⇒ nil

    Yields:

    • (arr)

    Returns:

    • (nil) 


3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
 
# File 'array.c', line 3240

static VALUE
rb_ary_zip(int argc, VALUE *argv, VALUE ary)
{
    int i, j;
    long len = RARRAY_LEN(ary);
    VALUE result = Qnil;

    for (i=0; i<argc; i++) {
	argv[i] = take_items(argv[i], len);
    }

    if (rb_block_given_p()) {
	int arity = rb_block_arity();

	if (arity > 1) {
	    VALUE work, *tmp;

	    tmp = ALLOCV_N(VALUE, work, argc+1);

	    for (i=0; i<RARRAY_LEN(ary); i++) {
		tmp[0] = RARRAY_AREF(ary, i);
		for (j=0; j<argc; j++) {
		    tmp[j+1] = rb_ary_elt(argv[j], i);
		}
		rb_yield_values2(argc+1, tmp);
	    }

	    if (work) ALLOCV_END(work);
	}
	else {
	    for (i=0; i<RARRAY_LEN(ary); i++) {
		VALUE tmp = rb_ary_new2(argc+1);

		rb_ary_push(tmp, RARRAY_AREF(ary, i));
		for (j=0; j<argc; j++) {
		    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
		}
		rb_yield(tmp);
	    }
	}
    }
    else {
	result = rb_ary_new_capa(len);

	for (i=0; i<len; i++) {
	    VALUE tmp = rb_ary_new_capa(argc+1);

	    rb_ary_push(tmp, RARRAY_AREF(ary, i));
	    for (j=0; j<argc; j++) {
		rb_ary_push(tmp, rb_ary_elt(argv[j], i));
	    }
	    rb_ary_push(result, tmp);
	}
    }

    return result;
}

#|(other_ary) ⇒ Object

Set Union — Returns a new array by joining ary with other_ary, excluding any duplicates and preserving the order from the original array.

It compares elements using their #hash and #eql? methods for efficiency.

[ "a", "b", "c" ] | [ "c", "d", "a" ]    #=> [ "a", "b", "c", "d" ]

See also Array#uniq.



4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
 
# File 'array.c', line 4097

static VALUE
rb_ary_or(VALUE ary1, VALUE ary2)
{
    VALUE hash, ary3;
    long i;

    ary2 = to_ary(ary2);
    hash = ary_make_hash(ary1);

    for (i=0; i<RARRAY_LEN(ary2); i++) {
	VALUE elt = RARRAY_AREF(ary2, i);
	if (!st_update(RHASH_TBL_RAW(hash), (st_data_t)elt, ary_hash_orset, (st_data_t)elt)) {
	    RB_OBJ_WRITTEN(hash, Qundef, elt);
	}
    }
    ary3 = rb_hash_values(hash);
    ary_recycle_hash(hash);
    return ary3;
}