On 28/07/13 18:07, Alan Gauld wrote:
Comparison operators haven't depended on cmp() for a long time. You can
google "rich comparison operators" for more info:
https://duckduckgo.com/?q=rich%20comparison%20operators
I only read the first two but one question remains:
If cmp() is gone is __cmp__() still supported? I'm assuming it
must be for backward compatibility?
Not in Python 3, it's gone. In Python 3, you have to define all six the rich
comparison methods __eq__ __ne__ __lt__ __gt__ __le__ __ge__ if you wish to
support the comparison operators. There's a helper function in functools to
help simplify the job:
@functools.total_ordering
class MyClass:
...
total_ordering will automatically fill in the missing comparison methods using
rules like these:
"<=" is equivalent to "not >"
">=" is equivalent to "not <"
"!=" is equivalent to "not =="
"<=" is equivalent to "< or =="
">=" is equivalent to "> or =="
--
Steven
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