Op 2005-08-30, Robert Kern schreef <[EMAIL PROTECTED]>: > Bryan Olson wrote: > >> Currently, user-defined classes can implement Python >> subscripting and slicing without implementing Python's len() >> function. In our proposal, the '$' symbol stands for the >> sequence's length, so classes must be able to report their >> length in order for $ to work within their slices and >> indexes. >> >> Specifically, to support new-style slicing, a class that >> accepts index or slice arguments to any of: >> >> __getitem__ >> __setitem__ >> __delitem__ >> __getslice__ >> __setslice__ >> __delslice__ >> >> must also consistently implement: >> >> __len__ >> >> Sane programmers already follow this rule. > > Incorrect. Some sane programmers have multiple dimensions they need to > index.
I don't see how that contradicts Bryan's statement. > from Numeric import * > A = array([[0, 1], [2, 3], [4, 5]]) > A[$-1, $-1] > > The result of len(A) has nothing to do with the second $. But that is irrelevant to the fact wether or not sane programmes follow Bryan's stated rule. That the second $ has nothing to do with len(A), doesn't contradict __len__ has to be implemented nor that sane programers already do. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list