Hallvard B Furuseth wrote: > Terry Reedy writes: >> If you want to duplicate 2.x behavior, which does *not* work for all >> types... >> >> def py2key(item): return (str(type(item)), item) > > Nope. > sorted((-1, 2, True, False)) == [-1, False, True, 2] > sorted((-1, 2, True, False), key=py2key) == [False, True, -1, 2] > Might often be good enough though. But uses more memory.
Compared to what? To the current 2.x default implementation? Or compared to an emulation of that, in 2.x, in a pure-Python function, passed as a cmp= argument? I think this one is *more* memory-efficient than a cmp function. Calling a cmp function will always allocate a frame object, for each comparison, giving you O(n log n) frame objects being created. OTOH, the key function will only be called O(n) times, causing the allocation of only O(n) objects. Of course, the peak memory usage is higher with the key function (O(n), compared to O(1) for the cmp= function, assuming the frame objects get deallocated and reused immediately). Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
