--- Regexp.last_match

    ȥפǺǸ˹Ԥäɽޥå MatchData 
    ֥Ȥ֤ޤΥ᥽åɤθƤӽФ $~ 
    λȤƱǤ

        /(.)(.)/ =~ "ab"
        p Regexp.last_match      # => #<MatchData:0x4599e58>
        p Regexp.last_match[0]   # => "ab"
        p Regexp.last_match[1]   # => "a"
        p Regexp.last_match[2]   # => "b"
        p Regexp.last_match[3]   # => nil

--- Regexp.last_match([nth])   ruby 1.7 feature

     nth  0 ξ硢ޥåʸ֤ޤ
    ($&)ʳǤϡnth ܤγ̤˥ޥå
    ʬʸ֤ޤ($1,$2,...)
    б̤ʤޥåʤäˤ nil ֤
    ޤ

        /(.)(.)/ =~ "ab"
        p Regexp.last_match      # => #<MatchData:0x4599e58>
        p Regexp.last_match(0)   # => "ab"
        p Regexp.last_match(1)   # => "a"
        p Regexp.last_match(2)   # => "b"
        p Regexp.last_match(3)   # => nil

    ɽΤޥåʤä硢ʤ 
    Regexp.last_match nil ֤ᡢ
    last_match[1] ηǤ㳰 NameError ȯޤ
    Фơlast_match(1)  nil ֤ޤ

