End of Life Ruby 3.2 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →
instance method
MatchData#[]
matchdata[index] → string or nil
matchdata[start, length] → array
matchdata[range] → array
matchdata[name] → string or nil
re.c
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static VALUE
match_aref(int argc, VALUE *argv, VALUE match)
{
VALUE idx, length;
match_check(match);
rb_scan_args(argc, argv, "11", &idx, &length);
if (NIL_P(length)) {
if (FIXNUM_P(idx)) {
return rb_reg_nth_match(FIX2INT(idx), match);
}
else {
int num = namev_to_backref_number(RMATCH_REGS(match), RMATCH(match)->regexp, idx);
if (num >= 0) {
return rb_reg_nth_match(num, match);
}
else {
return match_ary_aref(match, idx, Qnil);
}
}
}
else {
long beg = NUM2LONG(idx);
long len = NUM2LONG(length);
long num_regs = RMATCH_REGS(match)->num_regs;
if (len < 0) {
return Qnil;
}
if (beg < 0) {
beg += num_regs;
if (beg < 0) return Qnil;
}
else if (beg > num_regs) {
return Qnil;
}
if (beg+len > num_regs) {
len = num_regs - beg;
}
return match_ary_subseq(match, beg, len, Qnil);
}
}
When arguments index, +start and length, or range are given, returns match and captures in the style of Array#[]:
Example
m = /(.)(.)(\d+)(\d)/.match("THX1138.") # => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8"> m[0] # => "HX1138" m[1, 2] # => ["H", "X"] m[1..3] # => ["H", "X", "113"] m[-3, 2] # => ["X", "113"]
When string or symbol argument name is given, returns the matched substring for the given name:
Example
m = /(?<foo>.)(.)(?<bar>.+)/.match("hoge") # => #<MatchData "hoge" foo:"h" bar:"ge"> m['foo'] # => "h" m[:bar] # => "ge"