'while' in list comprehension?

[Terry Reedy]

"jsaul" <jsaul at gmx.de> wrote in message
news:20031022175924.GA10716 at jsaul.de...
> Hi there,
>
> wouldn't it be useful to have a 'while' conditional in addition to
> 'if' in list comprehensions?
>
>     foo = []
>     for i in bar:
>         if len(i) == 0:
>             break
>         foo.append(i)
>
> would then turn into
>
>     foo = [ i for i in bar while len(i)>0 ]

while is simply not same as if: break!
if executes once for each value of i, while indefinitely.
If you translate back by current rule, which will not change, you get:

foo = []
for i in bar:
    while len(i) >0:
         foo.append(i)

Terry J. Reedy