[Python-ideas] "While" suggestion

[BJörn Lindqvist]

On Thu, Jul 3, 2008 at 9:38 PM, Mike Meyer <mwm at mired.org> wrote:
>> #while True idiom (current Python)
>> while True:
>>     number = random.randint(1, 100)
>>     if number not in picked_numbers:
>>         break
>
> I don't believe that actually qualifies as "current python", any more
> than the other current alternative:
>
> # duplicate setup (current Python)
> number = random.randint(1, 100)
> while number in picked_numbers:
>   number = random.randint(1, 100)
>
> does.
>
> Both bits of code smell. One has the duplicated line; one has a test
> of a constant and a block exiting from the middle, all of which make
> the code slightly less clear.

Yup. Non-for loops just aren't very strong in Python.

> I tend to write either one, depending on what the duplicated code
> looks like. For this case, I actually prefer the latter. On the other
> hand, I'd probably write this one using a *third* alternative idiom:
>
> # Picked initial value (current Python)
> number = picked_numbers[0]
> while number in picked_numbers:
>   number = random.randint(1, 100)

I didn't say that the picked_numbers list had to be non-empty so you lose. :)


-- 
mvh Björn