[Python-ideas] Control Flow - Never Executed Loop Body

[Robert Collins]

On 21 March 2016 at 12:23, Vito De Tullio <vito.detullio at gmail.com> wrote:
> Andrew Barnert via Python-ideas wrote:
>
>> More generally, I think if this feature were to be added, "empty" is a
>> reasonable name. The idiomatic way to write it today is something like:
>>
>>     elem = empty = object()
>>     for elem in seq:
>>         do_stuff(elem)
>>     if elem is empty:
>>         do_empty_seq_stuff()
>>
>> So you're basically looking for syntactic sugar that abbreviated "if ...
>> is empty:", right?
>
> Maybe I'm missing something, but shoulnd't be like
>
>     if seq:
>         for elem in seq:
>             do_stuff(elem)
>     else:
>         do_empty_seq_stuff()
>
> a trivial code handling an empty list?

seq = iter([])

will cause your example to not run do_empty_seq_stuff().

-Rob


-- 
Robert Collins <rbtcollins at hpe.com>
Distinguished Technologist
HP Converged Cloud