Travis Griggs wrote:
> Subject nearly says it all.
>
> If i’m using pathlib, what’s the simplest/idiomatic way to simply count
> how many files are in a given directory?
>
> I was surprised (at first) when
>
> len(self.path.iterdir())
>
> I don’t say anything on the in the .stat() object that helps me.
>
> I could of course do the 4 liner:
>
> count = 0
> for _ in self.path.iterdir():
> count += 1
> return count
>
> The following seems to obtuse/clever for its own good:
>
> return sum(1 for _ in self.path.iterdir())
Put the "cleverness" into its own function
def iterlen(items):
return sum(1 for _ items)
num_files = iterlen(path.iterdir())
With the proper unit tests in place you may even switch to more exotic
approaches later:
def iterlen(items):
"""Exhaust an iterator an return the number of items.
Does not check for a __len__() method.
>>> iterlen(())
0
>>> iterlen([42])
1
>>> iterlen("abc")
3
>>> class A:
... def __len__(self): return 42
... def __iter__(self): yield from "abc"
>>> a = A()
>>> len(a)
42
>>> iterlen(a)
3
"""
d = collections.deque(enumerate(items, 1), maxlen=1)
return d.pop()[0] if d else 0
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