So, Python 2.5 will have new any() and all() functions. http://www.python.org/dev/peps/pep-0356/
any(seq) returns True if any value in seq evaluates true, False otherwise. all(seq) returns True if all values in seq evaluate true, False otherwise. I have a question: what should these functions return when seq is an empty list? Here is Guido's original article where he suggested any() and all(): http://www.artima.com/weblogs/viewpost.jsp?thread=98196 He offered this sample code for the semantics of any() and all(): def any(S): for x in S: if x: return True return False def all(S): for x in S: if not x: return False return True And he pointed out how nifty it is to combine generator functions with these two new functions: any(x > 42 for x in S) # True if any elements of S are > 42 all(x != 0 for x in S) # True if all elements if S are nonzero I'm completely on board with the semantics for any(). But all() bothers me. If all() receives an empty list, it will return True, and I don't like that. To me, all() should be a more restrictive function than any(), and it bothers me to see a case where any() returns False but all() returns True. In the all() example, if there *are* no values in S, then none of the values can be != 0, and IMHO all() should return False. Therefore, I propose that all() should work as if it were written this way: def all(S): ret_val = False for x in S: ret_val = True if not x: return False return ret_val Comments? P.S. I searched with Google, and with Google Groups, trying to find anyplace this might have been discussed before. Apologies if this has already been discussed and I missed it somehow. -- Steve R. Hastings "Vita est" [EMAIL PROTECTED] http://www.blarg.net/~steveha -- http://mail.python.org/mailman/listinfo/python-list
