Tim Chase wrote:
I still prefer "Return False if any element of the iterable is not true" or "Return False if any element in the iterable is false" because that describes exactly what the algorithm does. Granted, anybody with a mote of Python skills can tell that from the algorithm, but if you're going to go to the trouble of documenting, you might as well document what it does. The code in the docs do not check the truthiness of each element, it checks for the falseness (not-trueness) of each element. One might be able to defend it using logical manipulations, but since Python strives for clarity...
Arnaud Delobelle wrote:
IMO, you can't get around the essential ambiguity of the words "all", "any", "every", "no", etc. in the plain-English realm. The only way around this is to have the definition focus on the *individual* element of the iterable, not on the *collection* of elements. So I think Arnaud is headed in the right direction. My own choice would be to ignore his (very reasonable) objection to a definition that "makes it much less obvious what the function is for", and go with these:Return False as soon as the first false element in the iterable is found. Otherwise return True when the iterable is exhausted.Unfortunately it makes it much less obvious what the function is for and the Python implementation is a clearer explanation IMHO. So in the end, I think the doc reaches a good compromise: a short easy to understand english description that gives a clear idea of what all() is for, and a sample implementation for those who need/want the exact behaviour.
all(iterable) -- Return True if there does not exist an element in iterable that is False any(iterable) -- Return False if there does not exist an element in iterable that is True
These definitions *imply* the functions' short-circuiting behavior, but aren't as good as Arnaud's definition, which makes the short-circuiting explicit.
-John -- http://mail.python.org/mailman/listinfo/python-list
