instance method

MatchData#named_captures

() -> ::Hash[::String, ::String?]

(symbolize_names: true) -> ::Hash[::Symbol, ::String?]

(symbolize_names: ::boolish) -> ::Hash[::String | ::Symbol, ::String?]

named_captures(symbolize_names: false) → hash

static VALUE
match_named_captures(int argc, VALUE *argv, VALUE match)
{
    VALUE hash;
    struct MEMO *memo;

    match_check(match);
    if (NIL_P(RMATCH(match)->regexp))
        return rb_hash_new();

    VALUE opt;
    VALUE symbolize_names = 0;

    rb_scan_args(argc, argv, "0:", &opt);

    if (!NIL_P(opt)) {
        static ID keyword_ids[1];

        VALUE symbolize_names_val;

        if (!keyword_ids[0]) {
            keyword_ids[0] = rb_intern_const("symbolize_names");
        }
        rb_get_kwargs(opt, keyword_ids, 0, 1, &symbolize_names_val);
        if (!UNDEF_P(symbolize_names_val) && RTEST(symbolize_names_val)) {
            symbolize_names = 1;
        }
    }

    hash = rb_hash_new();
    memo = MEMO_NEW(hash, match, symbolize_names);

    onig_foreach_name(RREGEXP(RMATCH(match)->regexp)->ptr, match_named_captures_iter, (void*)memo);

    return hash;
}

Returns a hash of the named captures; each key is a capture name; each value is its captured string or nil:

Example

m = /(?<foo>.)(.)(?<bar>.+)/.match("hoge")
# => #<MatchData "hoge" foo:"h" bar:"ge">
m.named_captures # => {"foo"=>"h", "bar"=>"ge"}

m = /(?<a>.)(?<b>.)/.match("01")
# => #<MatchData "01" a:"0" b:"1">
m.named_captures #=> {"a" => "0", "b" => "1"}

m = /(?<a>.)(?<b>.)?/.match("0")
# => #<MatchData "0" a:"0" b:nil>
m.named_captures #=> {"a" => "0", "b" => nil}

m = /(?<a>.)(?<a>.)/.match("01")
# => #<MatchData "01" a:"0" a:"1">
m.named_captures #=> {"a" => "1"}

If keyword argument symbolize_names is given a true value, the keys in the resulting hash are Symbols:

Example

m = /(?<a>.)(?<a>.)/.match("01")
# => #<MatchData "01" a:"0" a:"1">
m.named_captures(symbolize_names: true) #=> {:a => "1"}

Ruby version changes

3.3
- MatchData#named_captures now accepts optional symbolize_names keyword. [Feature #19591]

See also #match_length #names #match #offset also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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