--- uniq
--- uniq!

    uniq 󤫤ʣǤ֤ޤ
    줿Ǥʬ˵ͤޤuniq! Ϻ˲
    Ū˹ԤԤ줿 self 򡢤Ǥʤ 
    nil ֤ޤ

    ǤνʣȽϡObject#eql? [Object/eql?] ˤԤޤ

    :
        p [1, 1, 1].uniq         #=> [1]
        p [1, 4, 1].uniq         #=> [1, 4]
        p [1, 3, 2, 2, 3].uniq   #=> [1, 3, 2]

