#!/usr/local/bin/python2 l1 = range(10) l2 = range(10) b = 11 for i in xrange(100000): g = len(l1) f = l1[:] f.append(b) f.extend(l2) [e for e in f][g] '''l1 = l1[:] l2 = l2[:] b = b for e in l1: pass b = b for e in l2: pass b'''