[Python-ideas] Python-ideas Digest, Vol 131, Issue 106

[Petr Viktorin]

On 10/31/2017 09:54 AM, Koos Zevenhoven wrote:
> On Tue, Oct 31, 2017 at 10:01 AM, Chris Angelico <rosuav at gmail.com 
> <mailto:rosuav at gmail.com>>wrote:
> 
>     On Tue, Oct 31, 2017 at 6:46 PM, Steven D'Aprano
>     <steve at pearwood.info <mailto:steve at pearwood.info>> wrote:
>     > On Tue, Oct 31, 2017 at 06:02:34PM +1100, Chris Angelico wrote:
>     >> One small change: If you use next(i) instead of i.next(), your code
>     >> should work on both Py2 and Py3. But other than that, I think it's
>     >> exactly the same as most people would expect of this function.
>     >
>     > Not me. As far as I can tell, that's semantically equivalent to:
>     >
>     > def single(i):
>     >     result, = i
>     >     return result
>     >
>     > apart from slightly different error messages.
> 
>     I saw the original code as being like the itertools explanatory
>     functions - you wouldn't actually USE those functions, but they tell
>     you what's going on when you use the simpler, faster, more compact
>     form.
> 
> 
> ​I wonder if that's more easily understood if you write it along these 
> line(s):
> 
>    (the_bob,) = ​(name for name in ('bob','fred') if name=='bob')

There are (unfortunately) several ways to do it. I prefer one that 
avoids a trailing comma:

[the_bob] = ​(name for name in ('bob','fred') if name=='bob')