add count

[mrocklin]

No description provided.

[eriknw]

I'm not sure about the name "count", because it may be confused with itertools.count. Also, see:

http://stackoverflow.com/questions/3345785/getting-number-of-elements-in-an-iterator-in-python/15112059#15112059

[eigenhombre]

+1 for merge if needed soon. I suspect there are optimizations for cases where the type of count's argument is tuple or list. But that can come later.

[eriknw]

How about calling it length, since it's a general function that returns the length of iterables/genrators/etc? Another option is ilen since it mimics len, but I prefer length, because it's more clear. And, sure, optimization can come later.

[eigenhombre]

I'm very used to thinking of count doing what this function does, though I can live w/ length.

[eriknw]

Yeah, this behavior of count makes sense to me too, but I think we need to be careful about using the same names as functions in the standard library.

[eriknw]

By the way, I am becoming increasingly supportive of count despite my concerns above. Still, it may be a good idea to add something like "not to be confused with itertools.count" in the docstring.

[mrocklin]

Added. Merging soon.