How do I check all variables returned buy the functions exists

[Bill]

Robin Becker wrote:
> On 16/09/2017 01:58, Steve D'Aprano wrote:
> ........
>>
>> If you want to test for None specifically:
>>
>> if any(v is None for v in values):
>>      print "at least one value was None"
>>
> .......
>
> for some reason that seems slow on my machine when compared with
>
> if None in values:
>    .....
>
>
This does not seem particularly surprising.  "None in values" is known 
as soon as None is found.
In "any(v is None for v in values)",  "any" probably isn't called until 
its argument is (fully) known.  Of course the results would depend on 
the implementation.  It would be interesting to compare the results if 
you used the optimize option (it's either -o or -O).

Bill



>> C:\usr\share\robin\pythonDoc>python -m timeit -s"values=(1,2,None)" 
>> "any(v is None for v in values)"
>> 1000000 loops, best of 3: 0.62 usec per loop
>>
>> C:\usr\share\robin\pythonDoc>python -m timeit 
>> -s"values=(None,2,None)" "any(v is None for v in values)"
>> 1000000 loops, best of 3: 0.504 usec per loop
>>
>> C:\usr\share\robin\pythonDoc>python -m timeit 
>> -s"values=(None,2,None)" "None in values"
>> 10000000 loops, best of 3: 0.0309 usec per loop
>>
>> C:\usr\share\robin\pythonDoc>python -m timeit -s"values=(1,2,None)" 
>> "None in values"
>> 10000000 loops, best of 3: 0.097 usec per loop
>
> it also seems a bit less obvious