Pierre Barbier de Reuille wrote: > Best answer is : try it :) > use the "timeit" module (in the standard lib) to do so ...
Ok, import timeit s = """\ a,b,c1,c2 = zip(*[(x[2],x[4], x[2]-x[1], x[2] - x[3]) for x in z]) """ t = timeit.Timer(stmt=s,setup="z = [(1,2,3,4,5)]*1000") print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000) s ="""\ for x in z: a = x[2] b = x[4] c1 = x[2] - x[1] c2 = x[2] - x[3] """ t = timeit.Timer(stmt=s,setup="z = [(1,2,3,4,5)]*1000") print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000) for 30 elements: [EMAIL PROTECTED]:~/tmp> python test.py 32.90 usec/pass 21.53 usec/pass for 100 elements: [EMAIL PROTECTED]:~/tmp> python test.py 103.32 usec/pass 70.91 usec/pass for 100 elements: [EMAIL PROTECTED]:~/tmp> python test.py 1435.43 usec/pass 710.55 usec/pass What do we learn? It might look elegant but it is slow. I guess mainly because I do the iteration twice with the zip command. The 1000 element run seems to show what Guido means with "abuse of the argument passing machinery" Learned my lesson :) Thanks to all Oliver -- http://mail.python.org/mailman/listinfo/python-list
