On Fri, Apr 10, 2020 at 4:27 PM Elliott Dehnbostel <[email protected]>
wrote:
> *Consider the following trivial for-loop:*
>
> chars = "abcaaabkjzhbjacvb"
> seek = {'a','b','c'}
> count = 0for a in chars:
> if a in seek:
> count += 1
>
>
I would definitely not write it that way. Instead I would write:
for a in chars:
count += a in seek
Or quite likely simply:
count = sum(a in seek for a in chars)
Now your trivial example is ... well, trivial. Often we want to do
different things if the membership is or isn't satisfied. Sometimes we can
simplify like this:
stuff = [this if a in seek else that for a in chars]
> count = sum([1 for a in chars if a in seek])
>
> This is kinda-sorta going in the right direction, but it has a bunch of
noise for no reason. Booleans subclass ints, with True being a kind of 1
and False being a kind of 0. We don't need to restate that in the
comprehension. Also no need to build a separate if when you've already
stated the condition. Also, sum is perfectly happy (and ever so slightly
faster) dealing with a generator comprehension.
Neither the inline if nor your proposal deal with actual blocks:
for a in chars:
if a in seek:
do_this(a)
and_that(a)
else:
other_stuff(a)
still_more(a)
But neither do we actually need any shorter way to spell that, which is
already clear.
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