> >>> import operator > >>> [ operator.mul(x,2) for x in (4,5)] Why not simply * ? [ x * 2 for x in (4,5)] And you might surround it by tuple to gain a tuple tuple([ x * 2 for x in (4,5)]) Another way would be to use Numeric import Numeric a = Numeric.array((10,2), Numeric.Float32) a = a * 2 -- Regards, Diez B. Roggisch