On 1/28/2010 6:47 PM, Paul Boddie wrote:
On 27 Jan, 13:26, Xah Lee<xah...@gmail.com> wrote:
So, for practical reasons, i think a “key” parameter is fine. But
chopping off “cmp” is damaging. When your data structure is complex,
its order is not embedded in some “key”. Taking out “cmp” makes it
impossible to sort your data structure.
What would annoy me if I used Python 3.x would be the apparent lack of
the __cmp__ method for conveniently defining comparisons between
instances of my own classes. Having to define all the rich comparison
methods frequently isn't even as much fun as it sounds.
You define __eq__, which automatically generates __ne__.
You define __lt__, which is all sort and heap need.
This should be about as easier than __eq__, which is really needed, and
__cmp__. If you need the other 3, either copy the recipe in the
Cookbook, or, even faster
def __ge__(s,o): return o.__lt__(s)
def __le__(s,o): return s < o or s == o
def __ge__(s,o): return s > o or s == o
All done.
Terry Jan Reedy
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