[Python-Dev] tally (and other accumulators)

[Raymond Hettinger]

[Alex] 
> This is quite general and simple at the same time: for example, it  
> was proposed originally to answer some complaint about any and all  
> giving no indication of the count of true/false items:
> 
> tally(bool(x) for x in seq)
> 
> would give a dict with two entries, counts of true and false items.

FWIW, sum() works nicely for counting true entries:

    >>> sum(x%3==0 for x in range(100))
   34


Raymond