"Paul F. Dubois" wrote:

The doc source is not available. I try to keep it up to date. If you would tell me the section I overlooked I will fix it.

That would be: Special Topics: Comparisons

As to logical and and or, they are not available for overload in the rich comparisons schema. That's a Python decision.

I figured as much. I just took a look at PEP 207: Rich Comparisons, and interestingly enough, the orignal version by David Asher addressed this issue (at least in terms of chaining comparisons, such as a > b >c). In the final PEP, I foound this: 5 In the current proposal, when A<B returns an array of elementwise comparisons, this outcome is considered non-Boolean, and its interpretation as Boolean by the shortcut operators raises an exception. David Ascher's proposal tries to deal with this; I don't think this is worth the additional complexity in the code generator. Instead of A<B<C, you can write (A<B)&(B<C). I'm curious about the statement "I don't think this is worth the additional complexity". It seems like being able to override the boolean operators would be VERY useful, and it seems odd how quickly this was glossed over. It is extremely common to combine a boolean operator with a a comparison. Is it time for a "rich boolean operators" PEP, or was this really rejected for good reason? By the way, it doesn't seem to raise an exception for me, but it does give a wrong (uninuitive anyway)answer:

...

...

a = array([1,2,3]) b = array([3,2,1]) c = array([3,3,3]) a < b < c array([0, 1, 1])

Also, does (A<B)&(B<C) always work? Is this a reliable solution? What do the bitwise operators do with Numeric arrays? I guess the final question here is: Is it time for a "rich boolean operators" PEP, or was this really rejected for good reason? -- Christopher Barker, Ph.D. ChrisHBarker@home.net --- --- --- http://members.home.net/barkerlohmann ---@@ -----@@ -----@@ ------@@@ ------@@@ ------@@@ Oil Spill Modeling ------ @ ------ @ ------ @ Water Resources Engineering ------- --------- -------- Coastal and Fluvial Hydrodynamics -------------------------------------- ------------------------------------------------------------------------