"It's me" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Okay, I give up.
>
> What's the best way to count number of items in a list?
>
> For instance,
>
> a=[[1,2,4],4,5,[2,3]]
>
> I want to know how many items are there in a (answer should be 7 - I don't
> want it to be 4)
>
<snip>
I've sure seen a lot of questions about the flattening of lists. I found
this version of flatten somewhere, I thought I got it from the Python
Cookbook but I can't find it now. Perhaps it was posted here on c.l.py. I
*don't* claim authorship, I'm merely an admirer of such a clean-looking
solution.
def flatten(a):
if not isinstance(a, (tuple,list)): return [a]
if len(a)==0: return []
return flatten(a[0])+flatten(a[1:])
a = [[1, 2, 4], 4, 5, [2, 3], 6, [6], [], 'askjdf']
print len(flatten(a))
gives the value 10.
Considering how often this comes up, might there be a place for some sort of
flatten() routine in the std dist, perhaps itertools?
-- Paul
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