--- indexes(index_1, ... , index_n)
--- indices(index_1, ... , index_n)

    ưͤ򥤥ǥåȤǤ֤ޤϰϳ
    ǥåФƤ nil бޤ

    :
        ary = %w( a b c d e )
        p ary.indexes( 0, 2, 4 )          #=> ["a", "c", "e"]
        p ary.indexes( 3, 4, 5, 6, 35 )   #=> ["d", "e", nil, nil]
        p ary.indexes( 0, -1, -2 )        #=> ["a", "e", "d"]
        p ary.indexes( -4, -5, -6, -35 )  #=> ["b", "a", nil, nil]

    ruby 1.8 feature:
    Υ᥽åɤ version 1.8 Ǥϡobsolete Ǥ
    Ѥȷٹåɽޤ
     Array#values_at [Array/values_at] Ѥޤ

