--- self - other

    κ黻self  other Ǥ
    Ƥο֤ޤʣǤϼ
    ޤ

    other Ǥʤ to_ary ᥽åɤˤ
    ۤηѴߤޤ

    ruby 1.8 feature: ʣǤݻޤ

        p([1, 2, 1, 3, 1, 4, 1, 5] - [2, 3, 4, 5])
        => [1, 1, 1, 1]

