On Fri, Oct 24, 2014 at 7:07 AM, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> >> if j < 10: >> j += 1 >> else: >> j = 3 >> >> or: >> >> j = j + 1 if j < 10 else 3 >> >> or: >> >> j = (lambda: 3, lambda: j + 1)[j < 10]() > > Certainly not the third one. That's needlessly obfuscated for the sake of > premature optimization. This version is much better, and probably not only > simpler and easier to read but probably more efficient too: > > j = (3, j + 1)[j < 10]
Yes, the lambda approach falls victim to function calls being slow. $ python3 -m timeit -s "j = 5" "if j < 10: j+=1 > else: j=3" 10000000 loops, best of 3: 0.0513 usec per loop $ python3 -m timeit -s "j = 5" "j = j + 1 if j < 10 else 3" 10000000 loops, best of 3: 0.0519 usec per loop $ python3 -m timeit -s "j = 5" "j = (3, j+1)[j < 10]" 10000000 loops, best of 3: 0.0883 usec per loop $ python3 -m timeit -s "j = 5" "j = (lambda: 3, lambda: j+1)[j < 10]()" 1000000 loops, best of 3: 0.312 usec per loop -- https://mail.python.org/mailman/listinfo/python-list
