MatchData#match_length

match_length(n) → integer or nil

match_length(name) → integer or nil

static VALUE
match_nth_length(VALUE match, VALUE n)
{
    int i = match_backref_number(match, n);
    struct re_registers *regs = RMATCH_REGS(match);

    match_check(match);
    backref_number_check(regs, i);

    if (BEG(i) < 0)
        return Qnil;

    update_char_offset(match);
    const struct rmatch_offset *const ofs =
        &RMATCH_EXT(match)->char_offset[i];
    return LONG2NUM(ofs->end - ofs->beg);
}

Returns the length (in characters) of the matched substring corresponding to the given argument.

When non-negative argument n is given, returns the length of the matched substring for the nth match:

Example

m = /(.)(.)(\d+)(\d)(\w)?/.match("THX1138.")
# => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8" 5:nil>
m.match_length(0) # => 6
m.match_length(4) # => 1
m.match_length(5) # => nil

When string or symbol argument name is given, returns the length of the matched substring for the named match:

Example

m = /(?<foo>.)(.)(?<bar>.+)/.match("hoge")
# => #<MatchData "hoge" foo:"h" bar:"ge">
m.match_length('foo') # => 1
m.match_length(:bar)  # => 2

Ruby version changes

3.1
- MatchData#match_length is added [Feature #18172]

See also #match #named_captures #length #names also in 4.1 · 4.0 · 3.4 · 3.2 · 3.1

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