Having both if() and for() statements in one liner
Tim Chase
python.list at tim.thechases.com
Tue Sep 17 10:17:44 EDT 2013
On 2013-09-17 16:21, Ferrous Cranus wrote:
> I just want to say tot he program that
>
> that only run the for statement if and only if person=='George'
>
> I dont see nay reason as to why this fails
>
> perhaps like:
>
> for times in range(0, 5) if person=='George':
>
> but that fails too...
> there must be written on soem way.
The canonical way to do this is the obvious:
if person == "George":
for times in range(0, 5):
...
That said, you can do stupid things to abstract the logic like
def iterate_if(condition, iterable):
if condition:
for item in iterable:
yield item
which you can use something like
for times in iterate_if(person == "George", range(0,5)):
...
but I don't advise it. Mainly, because the iterable will be
evaluated when passed as an argument, which incurs the runtime cost.
In the canonical form, if the test isn't passed, the range(n,m) is
never even evaluated.
-tkc
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