On 22/02/07, Dick Moores <[EMAIL PROTECTED]> wrote: > But there's syntax(?) there I've never seen before. "['','-'][n<0]". > I see it works: > > >>> n = -6 > >>> ['','-'][n<0] > '-' > >>> n = 98 > >>> ['','-'][n<0] > '' > > What's this called? I'd like to look it up.
It's taking advantage of the fact that booleans (True, False) are integers. >>> 1 == True True >>> 0 == False True >>> ['zero', 'one'][True] 'one' It's more compact, but less clear (IMO), so I'm not a big fan. Hmm, and it may not be faster either: Morpork:~ repton$ python -m timeit -s 'n=13' 'x=["", "-"][n<0]' 1000000 loops, best of 3: 0.6 usec per loop Morpork:~ repton$ python -m timeit -s 'n=13' 'if n < 0:' ' x="-"' 'else:' ' x=""' 1000000 loops, best of 3: 0.251 usec per loop -- John. _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
