[MRAB]
>>> Some time after reading about Python 2.5 and how the built-in functions
>>> 'min' and 'max' will be getting a new 'key' argument, I wondered how
>>> they would treat those cases where the keys were the same, for example:
>>>
>>> L = ["four", "five"]
>>> print min(L, key = len), max(L, key = len)
>>>
>>> The result is:
>>>
>>> ('four', 'four')[Tim Peters] >> min() and max() both work left-to-right, and return the minimal or >> maximal element at the smallest index. [MRAB] > It doesn't say that in the documentation. Right, the /language/ doesn't define anything about which specific minimal or maximal element is returned. Since you specifically mentioned Python 2.5, I figured you were asking about CPython -- which has always behaved in the way I explained. >>> I would've thought that min(...) should return the same as >>> sorted(...)[0] (which it does) >> It does, but only because Python's sort is stable, so that minimal >> elements retain their original relative order. That implies that the >> minimal element with smallest original index will end up at index 0 >> after sorting. >>> and that max(...) should return the same as sorted(...)[-1] (which it doesn't). >> Right -- although I don't know why you'd expect that. > Strings have index(), find(), etc which work left-to-right and > rindex(), rfind(), etc which work right-to-left. > > Lists have index() but not rindex(). > > I just thought that if min() and max() work left-to-right then for > completeness there should also be rmin() and rmax(); alternatively, > min() should return sorted()[0] and max() should return sorted()[-1] > for symmetry (my personal preference). If you were to make either of those a feature request, I don't expect they'd gain traction -- I expect "who cares?" would be the common challenge, and "I do" wouldn't silence it ;-) Compelling use cases sometimes work to get a new feature, but "completeness" or "symmetry" almost never do on their own (they function more as sanity checks on proposed solutions to use cases). -- http://mail.python.org/mailman/listinfo/python-list
