On May 12, 2:04 pm, kj <no.em...@please.post> wrote: > <petpeeve>It seems that a similar "simplicity argument" was invoked > to strip the cmp option from sort in Python 3. Grrrr. Simplicity > is great, but when the drive for it starts causing useful functionality > to be thrown out, then it is going too far. Yes, I know that it > is possible to do everything that sort's cmp option does through > clever tricks with key, but grokking and coding this maneuver > requires a *lot* more Python-fu than cmp did, which makes this > functionality a lot less accessible to beginners that the intrinsic > complexity of the problem warrants. And for what? To get rid of > an *option* that could be easily disregarded by anyone who found > it too "complex"? It makes no sense to me.</petpeeve>
I didn't follow the discussion on cmp and Python 3, but I would assume one reason it was removed was for performance. cmp is very slow compared to key, and if there should be one obvious way to do it, it should probably be the way that runs faster. Also, while in many cases cmp can be easier to use than key, it would be possible for a naive person with a complicated data structure to come up with a cmp function that, e.g. sorted A > B, B > C, and C > A. It's impossible to come up with a key function that will break sort in that fashion. So, while I understand the frustration of having a favorite tool removed, I have no trouble believing that there were good reasons for the removal. Regards, Pat -- http://mail.python.org/mailman/listinfo/python-list
