Class: Regexp
Overview
Document-class: Regexp
A Regexp
holds a regular expression, used to match a pattern against strings. Regexps are created using the /.../
and %r{...}
literals, and by the Regexp::new
constructor.
:include: doc/re.rdoc
Constant Summary collapse
- IGNORECASE =
see Regexp.options and Regexp.new
INT2FIX(ONIG_OPTION_IGNORECASE)
- EXTENDED =
see Regexp.options and Regexp.new
INT2FIX(ONIG_OPTION_EXTEND)
- MULTILINE =
see Regexp.options and Regexp.new
INT2FIX(ONIG_OPTION_MULTILINE)
- FIXEDENCODING =
see Regexp.options and Regexp.new
INT2FIX(ARG_ENCODING_FIXED)
- NOENCODING =
see Regexp.options and Regexp.new
INT2FIX(ARG_ENCODING_NONE)
Class Method Summary collapse
-
.compile ⇒ Object
Synonym for
Regexp.new
. -
.escape ⇒ Object
Escapes any characters that would have special meaning in a regular expression.
-
.last_match ⇒ Object
The first form returns the
MatchData
object generated by the last successful pattern match. -
.quote ⇒ Object
Escapes any characters that would have special meaning in a regular expression.
-
.try_convert(obj) ⇒ nil
Try to convert obj into a Regexp, using to_regexp method.
-
.union ⇒ Object
Return a
Regexp
object that is the union of the given patterns, i.e., will match any of its parts.
Instance Method Summary collapse
-
#== ⇒ Object
Equality---Two regexps are equal if their patterns are identical, they have the same character set code, and their
casefold?
values are the same. -
#===(str) ⇒ Boolean
Case Equality---Synonym for
Regexp#=~
used in case statements. -
#=~(str) ⇒ Integer?
Match---Matches rxp against str.
-
#casefold? ⇒ Boolean
Returns the value of the case-insensitive flag.
-
#encoding ⇒ Encoding
Returns the Encoding object that represents the encoding of obj.
-
#eql? ⇒ Object
Equality---Two regexps are equal if their patterns are identical, they have the same character set code, and their
casefold?
values are the same. -
#fixed_encoding? ⇒ Boolean
Returns false if rxp is applicable to a string with any ASCII compatible encoding.
-
#hash ⇒ Fixnum
Produce a hash based on the text and options of this regular expression.
-
#initialize ⇒ Object
constructor
Constructs a new regular expression from pattern, which can be either a
String
or aRegexp
(in which case that regexp's options are propagated, and new options may not be specified (a change as of Ruby 1.8). If options is aFixnum
, it should be one or more of the constantsRegexp::EXTENDED
,Regexp::IGNORECASE
, andRegexp::MULTILINE
, or-ed together. Otherwise, if options is notnil
, the regexp will be case insensitive. When the lang parameter is 'n' or 'N' sets the regexp no encoding. -
#initialize_copy ⇒ Object
:nodoc:.
-
#inspect ⇒ String
Produce a nicely formatted string-version of rxp.
-
#match ⇒ Object
Returns a
MatchData
object describing the match, ornil
if there was no match. -
#named_captures ⇒ Hash
Returns a hash representing information about named captures of rxp.
-
#names ⇒ Array
Returns a list of names of captures as an array of strings.
-
#options ⇒ Fixnum
Returns the set of bits corresponding to the options used when creating this Regexp (see
Regexp::new
for details. Note that additional bits may be set in the returned options: these are used internally by the regular expression code. These extra bits are ignored if the options are passed toRegexp::new
. -
#source ⇒ String
Returns the original string of the pattern.
-
#to_s ⇒ String
Returns a string containing the regular expression and its options (using the
(?opts:source)
notation. This string can be fed back in toRegexp::new
to a regular expression with the same semantics as the original. (However,Regexp#==
may not return true when comparing the two, as the source of the regular expression itself may differ, as the example shows).Regexp#inspect
produces a generally more readable version of rxp. -
#~(rxp) ⇒ Integer?
Match---Matches rxp against the contents of
$_
.
Constructor Details
#new(string, [options [, lang]]) ⇒ Regexp #new(regexp) ⇒ Regexp #compile(string, [options [, lang]]) ⇒ Regexp #compile(regexp) ⇒ Regexp
Constructs a new regular expression from pattern, which can be either a String
or a Regexp
(in which case that regexp's options are propagated, and new options may not be specified (a change as of Ruby 1.8). If options is a Fixnum
, it should be one or more of the constants Regexp::EXTENDED
, Regexp::IGNORECASE
, and Regexp::MULTILINE
, or-ed together. Otherwise, if options is not nil
, the regexp will be case insensitive. When the lang parameter is 'n' or 'N' sets the regexp no encoding.
r1 = Regexp.new('^a-z+:\\s+\w+') #=> /^a-z+:\s+\w+/
r2 = Regexp.new('cat', true) #=> /cat/i
r3 = Regexp.new('dog', Regexp::EXTENDED) #=> /dog/x
r4 = Regexp.new(r2) #=> /cat/i
|
# File 're.c'
static VALUE
rb_reg_initialize_m(int argc, VALUE *argv, VALUE self)
{
onig_errmsg_buffer err = "";
int flags = 0;
VALUE str;
rb_encoding *enc;
const char *ptr;
long len;
if (argc == 0 || argc > 3) {
rb_raise(rb_eArgError, "wrong number of arguments (%d for 1..3)", argc);
}
|
Class Method Details
.compile ⇒ Object
Synonym for Regexp.new
.escape(str) ⇒ String .quote(str) ⇒ String
Escapes any characters that would have special meaning in a regular expression. Returns a new escaped string, or self if no characters are escaped. For any string, Regexp.new(Regexp.escape(str))=~str
will be true.
Regexp.escape('\*?{}.') #=> \\\*\?\{\}\.
|
# File 're.c'
static VALUE
rb_reg_s_quote(VALUE c, VALUE str)
{
return rb_reg_quote(reg_operand(str, TRUE));
}
|
.last_match ⇒ MatchData .last_match(n) ⇒ String
The first form returns the MatchData
object generated by the last successful pattern match. Equivalent to reading the global variable $~
. The second form returns the nth field in this MatchData
object. n can be a string or symbol to reference a named capture.
Note that the last_match
is local to the thread and method scope of the method that did the pattern match.
/c(.)t/ =~ 'cat' #=> 0
Regexp.last_match #=> #<MatchData "cat" 1:"a">
Regexp.last_match(0) #=> "cat"
Regexp.last_match(1) #=> "a"
Regexp.last_match(2) #=> nil
/(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ "var = val"
Regexp.last_match #=> #<MatchData "var = val" lhs:"var" rhs:"val">
Regexp.last_match(:lhs) #=> "var"
Regexp.last_match(:rhs) #=> "val"
|
# File 're.c'
static VALUE
rb_reg_s_last_match(int argc, VALUE *argv)
{
VALUE nth;
if (argc > 0 && rb_scan_args(argc, argv, "01", &nth) == 1) {
VALUE match = rb_backref_get();
int n;
if (NIL_P(match)) return Qnil;
n = match_backref_number(match, nth);
return rb_reg_nth_match(n, match);
}
|
.escape(str) ⇒ String .quote(str) ⇒ String
Escapes any characters that would have special meaning in a regular expression. Returns a new escaped string, or self if no characters are escaped. For any string, Regexp.new(Regexp.escape(str))=~str
will be true.
Regexp.escape('\*?{}.') #=> \\\*\?\{\}\.
|
# File 're.c'
static VALUE
rb_reg_s_quote(VALUE c, VALUE str)
{
return rb_reg_quote(reg_operand(str, TRUE));
}
|
.try_convert(obj) ⇒ nil
Try to convert obj into a Regexp, using to_regexp method. Returns converted regexp or nil if obj cannot be converted for any reason.
Regexp.try_convert(/re/) #=> /re/
Regexp.try_convert("re") #=> nil
o = Object.new
Regexp.try_convert(o) #=> nil
def o.to_regexp() /foo/ end
Regexp.try_convert(o) #=> /foo/
|
# File 're.c'
static VALUE
rb_reg_s_try_convert(VALUE dummy, VALUE re)
{
return rb_check_regexp_type(re);
}
|
.union(pat1, pat2, ...) ⇒ Regexp .union(pats_ary) ⇒ Regexp
Return a Regexp
object that is the union of the given patterns, i.e., will match any of its parts. The patterns can be Regexp objects, in which case their options will be preserved, or Strings. If no patterns are given, returns /(?!)/
. The behavior is unspecified if any given pattern contains capture.
Regexp.union #=> /(?!)/
Regexp.union("penzance") #=> /penzance/
Regexp.union("a+b*c") #=> /a\+b\*c/
Regexp.union("skiing", "sledding") #=> /skiing|sledding/
Regexp.union(["skiing", "sledding"]) #=> /skiing|sledding/
Regexp.union(/dogs/, /cats/i) #=> /(?-mix:dogs)|(?i-mx:cats)/
|
# File 're.c'
static VALUE
rb_reg_s_union_m(VALUE self, VALUE args)
{
VALUE v;
if (RARRAY_LEN(args) == 1 &&
!NIL_P(v = rb_check_array_type(rb_ary_entry(args, 0)))) {
return rb_reg_s_union(self, v);
}
|
Instance Method Details
#==(other_rxp) ⇒ Boolean #eql?(other_rxp) ⇒ Boolean
Equality---Two regexps are equal if their patterns are identical, they have the same character set code, and their casefold?
values are the same.
/abc/ == /abc/x #=> false
/abc/ == /abc/i #=> false
/abc/ == /abc/n #=> false
/abc/u == /abc/n #=> false
|
# File 're.c'
static VALUE
rb_reg_equal(VALUE re1, VALUE re2)
{
if (re1 == re2) return Qtrue;
if (TYPE(re2) != T_REGEXP) return Qfalse;
rb_reg_check(re1); rb_reg_check(re2);
if (FL_TEST(re1, KCODE_FIXED) != FL_TEST(re2, KCODE_FIXED)) return Qfalse;
if (RREGEXP(re1)->ptr->options != RREGEXP(re2)->ptr->options) return Qfalse;
if (RREGEXP_SRC_LEN(re1) != RREGEXP_SRC_LEN(re2)) return Qfalse;
if (ENCODING_GET(re1) != ENCODING_GET(re2)) return Qfalse;
if (memcmp(RREGEXP_SRC_PTR(re1), RREGEXP_SRC_PTR(re2), RREGEXP_SRC_LEN(re1)) == 0) {
return Qtrue;
}
|
#===(str) ⇒ Boolean
Case Equality---Synonym for Regexp#=~
used in case statements.
a = "HELLO"
case a
when /^[a-z]*$/; print "Lower case\n"
when /^[A-Z]*$/; print "Upper case\n"
else; print "Mixed case\n"
end
produces:
Upper case
|
# File 're.c'
VALUE
rb_reg_eqq(VALUE re, VALUE str)
{
long start;
str = reg_operand(str, FALSE);
if (NIL_P(str)) {
rb_backref_set(Qnil);
return Qfalse;
}
|
#=~(str) ⇒ Integer?
Match---Matches rxp against str.
/at/ =~ "input data" #=> 7
/ax/ =~ "input data" #=> nil
If =~
is used with a regexp literal with named captures, captured strings (or nil) is assigned to local variables named by the capture names.
/(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ " x = y "
p lhs #=> "x"
p rhs #=> "y"
If it is not matched, nil is assigned for the variables.
/(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ " x = "
p lhs #=> nil
p rhs #=> nil
This assignment is implemented in the Ruby parser. The parser detects 'regexp-literal =~ expression' for the assignment. The regexp must be a literal without interpolation and placed at left hand side.
The assignment does not occur if the regexp is not a literal.
re = /(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/
re =~ " x = y "
p lhs # undefined local variable
p rhs # undefined local variable
A regexp interpolation, #{}
, also disables the assignment.
rhs_pat = /(?<rhs>\w+)/
/(?<lhs>\w+)\s*=\s*#{rhs_pat}/ =~ "x = y"
p lhs # undefined local variable
The assignment does not occur if the regexp is placed at the right hand side.
" x = y " =~ /(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/
p lhs, rhs # undefined local variable
|
# File 're.c'
VALUE
rb_reg_match(VALUE re, VALUE str)
{
long pos = reg_match_pos(re, &str, 0);
if (pos < 0) return Qnil;
pos = rb_str_sublen(str, pos);
return LONG2FIX(pos);
}
|
#casefold? ⇒ Boolean
Returns the value of the case-insensitive flag.
/a/.casefold? #=> false
/a/i.casefold? #=> true
/(?i:a)/.casefold? #=> false
|
# File 're.c'
static VALUE
rb_reg_casefold_p(VALUE re)
{
rb_reg_check(re);
if (RREGEXP(re)->ptr->options & ONIG_OPTION_IGNORECASE) return Qtrue;
return Qfalse;
}
|
#encoding ⇒ Encoding
Returns the Encoding object that represents the encoding of obj.
|
# File 're.c'
VALUE
rb_obj_encoding(VALUE obj)
{
rb_encoding *enc = rb_enc_get(obj);
if (!enc) {
rb_raise(rb_eTypeError, "unknown encoding");
}
|
#==(other_rxp) ⇒ Boolean #eql?(other_rxp) ⇒ Boolean
Equality---Two regexps are equal if their patterns are identical, they have the same character set code, and their casefold?
values are the same.
/abc/ == /abc/x #=> false
/abc/ == /abc/i #=> false
/abc/ == /abc/n #=> false
/abc/u == /abc/n #=> false
|
# File 're.c'
static VALUE
rb_reg_equal(VALUE re1, VALUE re2)
{
if (re1 == re2) return Qtrue;
if (TYPE(re2) != T_REGEXP) return Qfalse;
rb_reg_check(re1); rb_reg_check(re2);
if (FL_TEST(re1, KCODE_FIXED) != FL_TEST(re2, KCODE_FIXED)) return Qfalse;
if (RREGEXP(re1)->ptr->options != RREGEXP(re2)->ptr->options) return Qfalse;
if (RREGEXP_SRC_LEN(re1) != RREGEXP_SRC_LEN(re2)) return Qfalse;
if (ENCODING_GET(re1) != ENCODING_GET(re2)) return Qfalse;
if (memcmp(RREGEXP_SRC_PTR(re1), RREGEXP_SRC_PTR(re2), RREGEXP_SRC_LEN(re1)) == 0) {
return Qtrue;
}
|
#fixed_encoding? ⇒ Boolean
Returns false if rxp is applicable to a string with any ASCII compatible encoding. Returns true otherwise.
r = /a/
r.fixed_encoding? #=> false
r =~ "\u{6666} a" #=> 2
r =~ "\xa1\xa2 a".force_encoding("euc-jp") #=> 2
r =~ "abc".force_encoding("euc-jp") #=> 0
r = /a/u
r.fixed_encoding? #=> true
r.encoding #=> #<Encoding:UTF-8>
r =~ "\u{6666} a" #=> 2
r =~ "\xa1\xa2".force_encoding("euc-jp") #=> ArgumentError
r =~ "abc".force_encoding("euc-jp") #=> 0
r = /\u{6666}/
r.fixed_encoding? #=> true
r.encoding #=> #<Encoding:UTF-8>
r =~ "\u{6666} a" #=> 0
r =~ "\xa1\xa2".force_encoding("euc-jp") #=> ArgumentError
r =~ "abc".force_encoding("euc-jp") #=> nil
|
# File 're.c'
static VALUE
rb_reg_fixed_encoding_p(VALUE re)
{
if (FL_TEST(re, KCODE_FIXED))
return Qtrue;
else
return Qfalse;
}
|
#hash ⇒ Fixnum
Produce a hash based on the text and options of this regular expression.
|
# File 're.c'
static VALUE
rb_reg_hash(VALUE re)
{
st_index_t hashval = reg_hash(re);
return LONG2FIX(hashval);
}
|
#initialize_copy ⇒ Object
:nodoc:
|
# File 're.c'
static VALUE
rb_reg_init_copy(VALUE copy, VALUE re)
{
onig_errmsg_buffer err = "";
const char *s;
long len;
if (copy == re) return copy;
rb_check_frozen(copy);
/* need better argument type check */
if (!rb_obj_is_instance_of(re, rb_obj_class(copy))) {
rb_raise(rb_eTypeError, "wrong argument type");
}
|
#inspect ⇒ String
Produce a nicely formatted string-version of rxp. Perhaps surprisingly, #inspect
actually produces the more natural version of the string than #to_s
.
/ab+c/ix.inspect #=> "/ab+c/ix"
|
# File 're.c'
static VALUE
rb_reg_inspect(VALUE re)
{
if (!RREGEXP(re)->ptr || !RREGEXP_SRC(re) || !RREGEXP_SRC_PTR(re)) {
return rb_any_to_s(re);
}
|
#match(str) ⇒ MatchData? #match(str, pos) ⇒ MatchData?
Returns a MatchData
object describing the match, or nil
if there was no match. This is equivalent to retrieving the value of the special variable $~
following a normal match. If the second parameter is present, it specifies the position in the string to begin the search.
/(.)(.)(.)/.match("abc")[2] #=> "b"
/(.)(.)/.match("abc", 1)[2] #=> "c"
If a block is given, invoke the block with MatchData if match succeed, so that you can write
pat.match(str) {|m| ...}
instead of
if m = pat.match(str)
...
end
The return value is a value from block execution in this case.
|
# File 're.c'
static VALUE
rb_reg_match_m(int argc, VALUE *argv, VALUE re)
{
VALUE result, str, initpos;
long pos;
if (rb_scan_args(argc, argv, "11", &str, &initpos) == 2) {
pos = NUM2LONG(initpos);
}
|
#named_captures ⇒ Hash
Returns a hash representing information about named captures of rxp.
A key of the hash is a name of the named captures. A value of the hash is an array which is list of indexes of corresponding named captures.
/(?<foo>.)(?<bar>.)/.named_captures
#=> {"foo"=>[1], "bar"=>[2]}
/(?<foo>.)(?<foo>.)/.named_captures
#=> {"foo"=>[1, 2]}
If there are no named captures, an empty hash is returned.
/(.)(.)/.named_captures
#=> {}
|
# File 're.c'
static VALUE
rb_reg_named_captures(VALUE re)
{
VALUE hash = rb_hash_new();
rb_reg_check(re);
onig_foreach_name(RREGEXP(re)->ptr, reg_named_captures_iter, (void*)hash);
return hash;
}
|
#names ⇒ Array
Returns a list of names of captures as an array of strings.
/(?<foo>.)(?<bar>.)(?<baz>.)/.names
#=> ["foo", "bar", "baz"]
/(?<foo>.)(?<foo>.)/.names
#=> ["foo"]
/(.)(.)/.names
#=> []
|
# File 're.c'
static VALUE
rb_reg_names(VALUE re)
{
VALUE ary = rb_ary_new();
rb_reg_check(re);
onig_foreach_name(RREGEXP(re)->ptr, reg_names_iter, (void*)ary);
return ary;
}
|
#options ⇒ Fixnum
Returns the set of bits corresponding to the options used when creating this Regexp (see Regexp::new
for details. Note that additional bits may be set in the returned options: these are used internally by the regular expression code. These extra bits are ignored if the options are passed to Regexp::new
.
Regexp::IGNORECASE #=> 1
Regexp::EXTENDED #=> 2
Regexp::MULTILINE #=> 4
/cat/.options #=> 0
/cat/ix.options #=> 3
Regexp.new('cat', true).options #=> 1
/\xa1\xa2/e.options #=> 16
r = /cat/ix
Regexp.new(r.source, r.options) #=> /cat/ix
|
# File 're.c'
static VALUE
rb_reg_options_m(VALUE re)
{
int options = rb_reg_options(re);
return INT2NUM(options);
}
|
#source ⇒ String
Returns the original string of the pattern.
/ab+c/ix.source #=> "ab+c"
Note that escape sequences are retained as is.
/\x20\+/.source #=> "\\x20\\+"
|
# File 're.c'
static VALUE
rb_reg_source(VALUE re)
{
VALUE str;
rb_reg_check(re);
str = rb_enc_str_new(RREGEXP_SRC_PTR(re),RREGEXP_SRC_LEN(re), rb_enc_get(re));
if (OBJ_TAINTED(re)) OBJ_TAINT(str);
return str;
}
|
#to_s ⇒ String
Returns a string containing the regular expression and its options (using the (?opts:source)
notation. This string can be fed back in to Regexp::new
to a regular expression with the same semantics as the original. (However, Regexp#==
may not return true when comparing the two, as the source of the regular expression itself may differ, as the example shows). Regexp#inspect
produces a generally more readable version of rxp.
r1 = /ab+c/ix #=> /ab+c/ix
s1 = r1.to_s #=> "(?ix-m:ab+c)"
r2 = Regexp.new(s1) #=> /(?ix-m:ab+c)/
r1 == r2 #=> false
r1.source #=> "ab+c"
r2.source #=> "(?ix-m:ab+c)"
|
# File 're.c'
static VALUE
rb_reg_to_s(VALUE re)
{
int options, opt;
const int embeddable = ONIG_OPTION_MULTILINE|ONIG_OPTION_IGNORECASE|ONIG_OPTION_EXTEND;
long len;
const UChar* ptr;
VALUE str = rb_str_buf_new2("(?");
char optbuf[5];
rb_encoding *enc = rb_enc_get(re);
rb_reg_check(re);
rb_enc_copy(str, re);
options = RREGEXP(re)->ptr->options;
ptr = (UChar*)RREGEXP_SRC_PTR(re);
len = RREGEXP_SRC_LEN(re);
again:
if (len >= 4 && ptr[0] == '(' && ptr[1] == '?') {
int err = 1;
ptr += 2;
if ((len -= 2) > 0) {
do {
opt = char_to_option((int )*ptr);
if (opt != 0) {
options |= opt;
}
|
#~(rxp) ⇒ Integer?
Match---Matches rxp against the contents of $_
. Equivalent to rxp =~ $_
.
$_ = "input data"
~ /at/ #=> 7
|
# File 're.c'
VALUE
rb_reg_match2(VALUE re)
{
long start;
VALUE line = rb_lastline_get();
if (TYPE(line) != T_STRING) {
rb_backref_set(Qnil);
return Qnil;
}
|