Class: Set
Overview
Set implements a collection of unordered values with no duplicates. This is a hybrid of Array’s intuitive inter-operation facilities and Hash’s fast lookup.
Set is easy to use with Enumerable objects (implementing each
). Most of the initializer methods and binary operators accept generic Enumerable objects besides sets and arrays. An Enumerable object can be converted to Set using the to_set
method.
Set uses Hash as storage, so you must note the following points:
-
Equality of elements is determined according to Object#eql? and Object#hash.
-
Set assumes that the identity of each element does not change while it is stored. Modifying an element of a set will render the set to an unreliable state.
-
When a string is to be stored, a frozen copy of the string is stored instead unless the original string is already frozen.
Comparison
The comparison operators <, >, <= and >= are implemented as shorthand for the proper_,subset?,superset? methods. However, the <=> operator is intentionally left out because not every pair of sets is comparable. (x,y vs. x,z for example)
Example
require 'set'
s1 = Set.new [1, 2] # -> #<Set: {1, 2}>
s2 = [1, 2].to_set # -> #<Set: {1, 2}>
s1 == s2 # -> true
s1.add("foo") # -> #<Set: {1, 2, "foo"}>
s1.merge([2, 6]) # -> #<Set: {1, 2, "foo", 6}>
s1.subset? s2 # -> false
s2.subset? s1 # -> true
Contact
- Akinori MUSHA <[email protected]> (current maintainer)
Direct Known Subclasses
Constant Summary collapse
- InspectKey =
:nodoc:
:__inspect_key__
Class Method Summary collapse
-
.[](*ary) ⇒ Object
Creates a new set containing the given objects.
Instance Method Summary collapse
-
#&(enum) ⇒ Object
(also: #intersection)
Returns a new set containing elements common to the set and the given enumerable object.
-
#-(enum) ⇒ Object
(also: #difference)
Returns a new set built by duplicating the set, removing every element that appears in the given enumerable object.
-
#==(other) ⇒ Object
Returns true if two sets are equal.
-
#^(enum) ⇒ Object
Returns a new set containing elements exclusive between the set and the given enumerable object.
-
#add(o) ⇒ Object
(also: #<<)
Adds the given object to the set and returns self.
-
#add?(o) ⇒ Boolean
Adds the given object to the set and returns self.
-
#classify ⇒ Object
Classifies the set by the return value of the given block and returns a hash of => set of elements pairs.
-
#clear ⇒ Object
Removes all elements and returns self.
-
#collect! ⇒ Object
(also: #map!)
Replaces the elements with ones returned by collect().
-
#delete(o) ⇒ Object
Deletes the given object from the set and returns self.
-
#delete?(o) ⇒ Boolean
Deletes the given object from the set and returns self.
-
#delete_if ⇒ Object
Deletes every element of the set for which block evaluates to true, and returns self.
-
#disjoint?(set) ⇒ Boolean
Returns true if the set and the given set have no element in common.
-
#divide(&func) ⇒ Object
Divides the set into a set of subsets according to the commonality defined by the given block.
-
#each(&block) ⇒ Object
Calls the given block once for each element in the set, passing the element as parameter.
-
#empty? ⇒ Boolean
Returns true if the set contains no elements.
-
#eql?(o) ⇒ Boolean
:nodoc:.
-
#flatten ⇒ Object
Returns a new set that is a copy of the set, flattening each containing set recursively.
-
#flatten! ⇒ Object
Equivalent to Set#flatten, but replaces the receiver with the result in place.
-
#freeze ⇒ Object
:nodoc:.
-
#hash ⇒ Object
:nodoc:.
-
#include?(o) ⇒ Boolean
(also: #member?)
Returns true if the set contains the given object.
-
#initialize(enum = nil, &block) ⇒ Set
constructor
Creates a new set containing the elements of the given enumerable object.
-
#initialize_copy(orig) ⇒ Object
Copy internal hash.
-
#inspect ⇒ Object
Returns a string containing a human-readable representation of the set.
-
#intersect?(set) ⇒ Boolean
Returns true if the set and the given set have at least one element in common.
-
#keep_if ⇒ Object
Deletes every element of the set for which block evaluates to false, and returns self.
-
#merge(enum) ⇒ Object
Merges the elements of the given enumerable object to the set and returns self.
-
#pretty_print(pp) ⇒ Object
:nodoc:.
-
#pretty_print_cycle(pp) ⇒ Object
:nodoc:.
-
#proper_subset?(set) ⇒ Boolean
(also: #<)
Returns true if the set is a proper subset of the given set.
-
#proper_superset?(set) ⇒ Boolean
(also: #>)
Returns true if the set is a proper superset of the given set.
-
#reject!(&block) ⇒ Object
Equivalent to Set#delete_if, but returns nil if no changes were made.
-
#replace(enum) ⇒ Object
Replaces the contents of the set with the contents of the given enumerable object and returns self.
-
#select!(&block) ⇒ Object
Equivalent to Set#keep_if, but returns nil if no changes were made.
-
#size ⇒ Object
(also: #length)
Returns the number of elements.
-
#subset?(set) ⇒ Boolean
(also: #<=)
Returns true if the set is a subset of the given set.
-
#subtract(enum) ⇒ Object
Deletes every element that appears in the given enumerable object and returns self.
-
#superset?(set) ⇒ Boolean
(also: #>=)
Returns true if the set is a superset of the given set.
-
#taint ⇒ Object
:nodoc:.
-
#to_a ⇒ Object
Converts the set to an array.
-
#to_set(klass = Set, *args, &block) ⇒ Object
Returns self if no arguments are given.
-
#untaint ⇒ Object
:nodoc:.
-
#|(enum) ⇒ Object
(also: #+, #union)
Returns a new set built by merging the set and the elements of the given enumerable object.
Constructor Details
#initialize(enum = nil, &block) ⇒ Set
Creates a new set containing the elements of the given enumerable object.
If a block is given, the elements of enum are preprocessed by the given block.
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# File 'lib/set.rb', line 80 def initialize(enum = nil, &block) # :yields: o @hash ||= Hash.new enum.nil? and return if block do_with_enum(enum) { |o| add(block[o]) } else merge(enum) end end |
Class Method Details
.[](*ary) ⇒ Object
Creates a new set containing the given objects.
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# File 'lib/set.rb', line 71 def self.[](*ary) new(ary) end |
Instance Method Details
#&(enum) ⇒ Object Also known as: intersection
Returns a new set containing elements common to the set and the given enumerable object.
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# File 'lib/set.rb', line 385 def &(enum) n = self.class.new do_with_enum(enum) { |o| n.add(o) if include?(o) } n end |
#-(enum) ⇒ Object Also known as: difference
Returns a new set built by duplicating the set, removing every element that appears in the given enumerable object.
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# File 'lib/set.rb', line 378 def -(enum) dup.subtract(enum) end |
#==(other) ⇒ Object
Returns true if two sets are equal. The equality of each couple of elements is defined according to Object#eql?.
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# File 'lib/set.rb', line 403 def ==(other) if self.equal?(other) true elsif other.instance_of?(self.class) @hash == other.instance_variable_get(:@hash) elsif other.is_a?(Set) && self.size == other.size other.all? { |o| @hash.include?(o) } else false end end |
#^(enum) ⇒ Object
Returns a new set containing elements exclusive between the set and the given enumerable object. (set ^ enum) is equivalent to ((set | enum) - (set & enum)).
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# File 'lib/set.rb', line 395 def ^(enum) n = Set.new(enum) each { |o| if n.include?(o) then n.delete(o) else n.add(o) end } n end |
#add(o) ⇒ Object Also known as: <<
Adds the given object to the set and returns self. Use merge
to add many elements at once.
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# File 'lib/set.rb', line 269 def add(o) @hash[o] = true self end |
#add?(o) ⇒ Boolean
Adds the given object to the set and returns self. If the object is already in the set, returns nil.
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# File 'lib/set.rb', line 277 def add?(o) if include?(o) nil else add(o) end end |
#classify ⇒ Object
Classifies the set by the return value of the given block and returns a hash of => set of elements pairs. The block is called once for each element of the set, passing the element as parameter.
e.g.:
require 'set'
files = Set.new(Dir.glob("*.rb"))
hash = files.classify { |f| File.mtime(f).year }
p hash # => {2000=>#<Set: {"a.rb", "b.rb"}>,
# 2001=>#<Set: {"c.rb", "d.rb", "e.rb"}>,
# 2002=>#<Set: {"f.rb"}>}
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# File 'lib/set.rb', line 437 def classify # :yields: o block_given? or return enum_for(__method__) h = {} each { |i| x = yield(i) (h[x] ||= self.class.new).add(i) } h end |
#clear ⇒ Object
Removes all elements and returns self.
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# File 'lib/set.rb', line 135 def clear @hash.clear self end |
#collect! ⇒ Object Also known as: map!
Replaces the elements with ones returned by collect().
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# File 'lib/set.rb', line 323 def collect! block_given? or return enum_for(__method__) set = self.class.new each { |o| set << yield(o) } replace(set) end |
#delete(o) ⇒ Object
Deletes the given object from the set and returns self. Use subtract
to delete many items at once.
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# File 'lib/set.rb', line 287 def delete(o) @hash.delete(o) self end |
#delete?(o) ⇒ Boolean
Deletes the given object from the set and returns self. If the object is not in the set, returns nil.
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# File 'lib/set.rb', line 294 def delete?(o) if include?(o) delete(o) else nil end end |
#delete_if ⇒ Object
Deletes every element of the set for which block evaluates to true, and returns self.
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# File 'lib/set.rb', line 304 def delete_if block_given? or return enum_for(__method__) # @hash.delete_if should be faster, but using it breaks the order # of enumeration in subclasses. select { |o| yield o }.each { |o| @hash.delete(o) } self end |
#disjoint?(set) ⇒ Boolean
Returns true if the set and the given set have no element in common. This method is the opposite of intersect?
.
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# File 'lib/set.rb', line 254 def disjoint?(set) !intersect?(set) end |
#divide(&func) ⇒ Object
Divides the set into a set of subsets according to the commonality defined by the given block.
If the arity of the block is 2, elements o1 and o2 are in common if block.call(o1, o2) is true. Otherwise, elements o1 and o2 are in common if block.call(o1) == block.call(o2).
e.g.:
require 'set'
numbers = Set[1, 3, 4, 6, 9, 10, 11]
set = numbers.divide { |i,j| (i - j).abs == 1 }
p set # => #<Set: {#<Set: {1}>,
# #<Set: {11, 9, 10}>,
# #<Set: {3, 4}>,
# #<Set: {6}>}>
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# File 'lib/set.rb', line 466 def divide(&func) func or return enum_for(__method__) if func.arity == 2 require 'tsort' class << dig = {} # :nodoc: include TSort alias tsort_each_node each_key def tsort_each_child(node, &block) fetch(node).each(&block) end end each { |u| dig[u] = a = [] each{ |v| func.call(u, v) and a << v } } set = Set.new() dig.each_strongly_connected_component { |css| set.add(self.class.new(css)) } set else Set.new(classify(&func).values) end end |
#each(&block) ⇒ Object
Calls the given block once for each element in the set, passing the element as parameter. Returns an enumerator if no block is given.
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# File 'lib/set.rb', line 261 def each(&block) block or return enum_for(__method__) @hash.each_key(&block) self end |
#empty? ⇒ Boolean
Returns true if the set contains no elements.
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# File 'lib/set.rb', line 130 def empty? @hash.empty? end |
#eql?(o) ⇒ Boolean
:nodoc:
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# File 'lib/set.rb', line 419 def eql?(o) # :nodoc: return false unless o.is_a?(Set) @hash.eql?(o.instance_variable_get(:@hash)) end |
#flatten ⇒ Object
Returns a new set that is a copy of the set, flattening each containing set recursively.
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# File 'lib/set.rb', line 189 def flatten self.class.new.flatten_merge(self) end |
#flatten! ⇒ Object
Equivalent to Set#flatten, but replaces the receiver with the result in place. Returns nil if no modifications were made.
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# File 'lib/set.rb', line 195 def flatten! if detect { |e| e.is_a?(Set) } replace(flatten()) else nil end end |
#freeze ⇒ Object
:nodoc:
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# File 'lib/set.rb', line 108 def freeze # :nodoc: @hash.freeze super end |
#hash ⇒ Object
:nodoc:
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# File 'lib/set.rb', line 415 def hash # :nodoc: @hash.hash end |
#include?(o) ⇒ Boolean Also known as: member?
Returns true if the set contains the given object.
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# File 'lib/set.rb', line 204 def include?(o) @hash.include?(o) end |
#initialize_copy(orig) ⇒ Object
Copy internal hash.
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# File 'lib/set.rb', line 104 def initialize_copy(orig) @hash = orig.instance_variable_get(:@hash).dup end |
#inspect ⇒ Object
Returns a string containing a human-readable representation of the set. (“#<Set: element2, …>”)
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# File 'lib/set.rb', line 500 def inspect ids = (Thread.current[InspectKey] ||= []) if ids.include?(object_id) return sprintf('#<%s: {...}>', self.class.name) end begin ids << object_id return sprintf('#<%s: {%s}>', self.class, to_a.inspect[1..-2]) ensure ids.pop end end |
#intersect?(set) ⇒ Boolean
Returns true if the set and the given set have at least one element in common.
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# File 'lib/set.rb', line 243 def intersect?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" if size < set.size any? { |o| set.include?(o) } else set.any? { |o| include?(o) } end end |
#keep_if ⇒ Object
Deletes every element of the set for which block evaluates to false, and returns self.
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# File 'lib/set.rb', line 314 def keep_if block_given? or return enum_for(__method__) # @hash.keep_if should be faster, but using it breaks the order of # enumeration in subclasses. reject { |o| yield o }.each { |o| @hash.delete(o) } self end |
#merge(enum) ⇒ Object
Merges the elements of the given enumerable object to the set and returns self.
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# File 'lib/set.rb', line 351 def merge(enum) if enum.instance_of?(self.class) @hash.update(enum.instance_variable_get(:@hash)) else do_with_enum(enum) { |o| add(o) } end self end |
#pretty_print(pp) ⇒ Object
:nodoc:
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# File 'lib/set.rb', line 515 def pretty_print(pp) # :nodoc: pp.text sprintf('#<%s: {', self.class.name) pp.nest(1) { pp.seplist(self) { |o| pp.pp o } } pp.text "}>" end |
#pretty_print_cycle(pp) ⇒ Object
:nodoc:
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# File 'lib/set.rb', line 525 def pretty_print_cycle(pp) # :nodoc: pp.text sprintf('#<%s: {%s}>', self.class.name, empty? ? '' : '...') end |
#proper_subset?(set) ⇒ Boolean Also known as: <
Returns true if the set is a proper subset of the given set.
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# File 'lib/set.rb', line 234 def proper_subset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if set.size <= size all? { |o| set.include?(o) } end |
#proper_superset?(set) ⇒ Boolean Also known as: >
Returns true if the set is a proper superset of the given set.
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# File 'lib/set.rb', line 218 def proper_superset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if size <= set.size set.all? { |o| include?(o) } end |
#reject!(&block) ⇒ Object
Equivalent to Set#delete_if, but returns nil if no changes were made.
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# File 'lib/set.rb', line 333 def reject!(&block) block or return enum_for(__method__) n = size delete_if(&block) size == n ? nil : self end |
#replace(enum) ⇒ Object
Replaces the contents of the set with the contents of the given enumerable object and returns self.
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# File 'lib/set.rb', line 142 def replace(enum) if enum.instance_of?(self.class) @hash.replace(enum.instance_variable_get(:@hash)) else clear merge(enum) end self end |
#select!(&block) ⇒ Object
Equivalent to Set#keep_if, but returns nil if no changes were made.
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# File 'lib/set.rb', line 342 def select!(&block) block or return enum_for(__method__) n = size keep_if(&block) size == n ? nil : self end |
#size ⇒ Object Also known as: length
Returns the number of elements.
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# File 'lib/set.rb', line 124 def size @hash.size end |
#subset?(set) ⇒ Boolean Also known as: <=
Returns true if the set is a subset of the given set.
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# File 'lib/set.rb', line 226 def subset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if set.size < size all? { |o| set.include?(o) } end |
#subtract(enum) ⇒ Object
Deletes every element that appears in the given enumerable object and returns self.
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# File 'lib/set.rb', line 363 def subtract(enum) do_with_enum(enum) { |o| delete(o) } self end |
#superset?(set) ⇒ Boolean Also known as: >=
Returns true if the set is a superset of the given set.
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# File 'lib/set.rb', line 210 def superset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if size < set.size set.all? { |o| include?(o) } end |
#taint ⇒ Object
:nodoc:
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# File 'lib/set.rb', line 113 def taint # :nodoc: @hash.taint super end |
#to_a ⇒ Object
Converts the set to an array. The order of elements is uncertain.
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# File 'lib/set.rb', line 154 def to_a @hash.keys end |
#to_set(klass = Set, *args, &block) ⇒ Object
Returns self if no arguments are given. Otherwise, converts the set to another with klass.new(self, *args, &block).
In subclasses, returns klass.new(self, *args, &block) unless overridden.
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# File 'lib/set.rb', line 163 def to_set(klass = Set, *args, &block) return self if instance_of?(Set) && klass == Set && block.nil? && args.empty? klass.new(self, *args, &block) end |
#untaint ⇒ Object
:nodoc:
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# File 'lib/set.rb', line 118 def untaint # :nodoc: @hash.untaint super end |
#|(enum) ⇒ Object Also known as: +, union
Returns a new set built by merging the set and the elements of the given enumerable object.
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# File 'lib/set.rb', line 370 def |(enum) dup.merge(enum) end |