MatchData

        # MatchData < Object

(from ruby core)
---
MatchData encapsulates the result of matching a Regexp against string.
It is returned by Regexp#match and String#match, and also stored in a
global variable returned by Regexp.last_match.

Usage:

    url = 'https://docs.ruby-lang.org/en/2.5.0/MatchData.html'
    m = url.match(/(\d\.?)+/)   # => #<MatchData "2.5.0" 1:"0">
    m.string                    # => "https://docs.ruby-lang.org/en/2.5.0/MatchData.html"
    m.regexp                    # => /(\d\.?)+/
    # entire matched substring:
    m[0]                        # => "2.5.0"

    # Working with unnamed captures
    m = url.match(%r{([^/]+)/([^/]+)\.html$})
    m.captures                  # => ["2.5.0", "MatchData"]
    m[1]                        # => "2.5.0"
    m.values_at(1, 2)           # => ["2.5.0", "MatchData"]

    # Working with named captures
    m = url.match(%r{(?<version>[^/]+)/(?<module>[^/]+)\.html$})
    m.captures                  # => ["2.5.0", "MatchData"]
    m.named_captures            # => {"version"=>"2.5.0", "module"=>"MatchData"}
    m[:version]                 # => "2.5.0"
    m.values_at(:version, :module)
                                # => ["2.5.0", "MatchData"]
    # Numerical indexes are working, too
    m[1]                        # => "2.5.0"
    m.values_at(1, 2)           # => ["2.5.0", "MatchData"]

## Global variables equivalence

Parts of last MatchData (returned by Regexp.last_match) are also aliased
as global variables:

*   `$~` is Regexp.last_match;
*   `$&` is Regexp.last_match`[ 0 ]`;
*   `$1`, `$2`, and so on are Regexp.last_match`[ i ]` (captures by
    number);
*   `$`` is Regexp.last_match`.pre_match`;
*   `$'` is Regexp.last_match`.post_match`;
*   `$+` is Regexp.last_match`[ -1 ]` (the last capture).


See also "Special global variables" section in Regexp documentation.
---
# Instance methods:

    ==
    []
    begin
    captures
    end
    eql?
    hash
    inspect
    length
    match
    match_length
    named_captures
    names
    offset
    post_match
    pre_match
    regexp
    size
    string
    to_a
    to_s
    values_at