Nick Coghlan added the comment:
It's a direct counterpart to any() and all() - first([0, [], ()]) is None for
the same reason that any([0, [], ()]) and all([0, [], ()]) are both False.
If first returned the actual first item in the iterable (regardless of truth
value), then it would just be "next" under a different name, which would be
rather pointless.
That said, if "first" is deemed too ambiguous, then I believe "filterednext"
would be a reasonable more explicit name:
>>> filterednext([0, None, False, [], (), 42])
42
>>> filterednext([0, None, False, [], ()], default=42)
42
>>> filterednext([1, 1, 3, 4, 5], key=lambda x: x % 2 == 0)
4
>>> m = filterednext(regexp.match('abc') for regexp in [re1, re2])
I also believe itertools would be a more appropriate initial home than the
builtins.
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<http://bugs.python.org/issue18652>
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