On Thu, 09 Jun 2005 08:10:09 -0400, Dan Sommers wrote: >>> The main problem is that Python is trying to stick at least three >>> different concepts onto the same set of operators: equivalence (are >>> these two objects the same?), ordering (in a sorted list, which comes >>> first?), and mathematical "size". [snip] >>> This gives the wacky world where >>> "[(1,2), (3,4)].sort()" works, whereas "[1+2j, 3+4j].sort()" doesn't. > > Python inherits that wackiness directly from (often wacky) world of > Mathematics. > > IMO, the true wackiness is that > > [ AssertionError, (vars, unicode), __name__, apply ].sort( ) > > "works," too. Python refusing to sort my list of complex numbers is a > Good Thing.
Only if you understand sorting as being related to the mathematical sense of size, rather than the sense of ordering. The two are not the same! If you were to ask, "which is bigger, 1+2j or 3+4j?" then you are asking a question about mathematical size. There is no unique answer (although taking the absolute value must surely come close) and the expression 1+2j > 3+4j is undefined. But if you ask "which should come first in a list, 1+2j or 3+4j?" then you are asking about a completely different thing. The usual way of sorting arbitrary chunks of data within a list is by dictionary order, and in dictionary order 1+2j comes before 3+4j because 1 comes before 3. This suggests that perhaps sort needs a keyword argument "style", one of "dictionary", "numeric" or "datetime", which would modify how sorting would compare keys. Perhaps in Python 3.0. -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
