Andrew Barnert via Python-ideas writes: > Is there any commonly used or even imaginable useful type that uses > them in weirder ways than set and float (which are both partially > ordered) or np.array (where they aren’t even Boolean-values)?
I've had occasion (a class for outcomes in two-player games) to define both < and <= as complete preorders, with "symmetry" in the sense that A < B iff B > A and A <= B iff B >= A, but < and <= were completely independent: they could be identical ("game of pure coordination"), they could be inverse ("game of pure competition"), and they could be anything else (eg, "prisoners' dilemma"). This system took a little getting used to, but writing "A > B and A >= B and A != B" [1] to implement "A Pareto dominates B" was one expressive convenience among others. I'm not sure this is "weird" in the sense you mean, and I greatly doubt this is sufficiently common to deserve an ABC :-), but it's a real example (long since archived on a disc whose exact location has slipped from memory ;-) that shows how flexible "ordering" in Python can be. Footnotes: [1] How the class, and specifically "A != B", were implemented is left for the reader who knows game theory to imagine. ;-) _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/772IG26DKONSV5WHCNSGWCF2OUFNXLQK/ Code of Conduct: http://python.org/psf/codeofconduct/