[Python-Dev] list comprehensions again...

Barry A. Warsaw bwarsaw@beopen.com
Tue, 11 Jul 2000 23:23:00 -0400 (EDT)

>>>>> "SM" == Skip Montanaro <skip@mojam.com> writes:

    BAW> Range literals I can see as being worth it.  I wonder if
    BAW> parallel for loops can't be handled more gracefully with a
    BAW> function -- isn't it just a nice wrapper around a specific
    BAW> call to map() anyway?

    SM> I believe Thomas proposed range literals to avoid calling the
    SM> range() function...

Right, and that seems totally cool to me.  Simple syntax, clear

    SM> Regarding a wrapper around map(), you will need a pretty hairy
    SM> wrapper, since you can do some pretty complex things with
    SM> Greg's version of list comprehensions.

I meant the parallel for loops as a shortcut for map().  List
comprehensions do seem more powerful, however:

    | print [s.strip() for s in spcs]
    | print [3 * x for x in nums]

Cool so far.

    | print [x for x in nums if x > 2]

Uh oh, starting to look like Perl...

    | print [i, s for i in nums for s in strs]
    | print [i, s for i in nums for s in [f for f in strs if "n" in f]]

Yow!  No one will accuse Python of only having one way to do it
anymore!  Even without the curse-word-symbols, I fear excessive scalp
exposing head-scratching when I see this in code.