Simon Forman wrote: > Dustan wrote: > > Can I make enumerate(myObject) act differently? > > > > class A(object): > > def __getitem__(self, item): > > if item > 0: > > return self.sequence[item-1] > > elif item < 0: > > return self.sequence[item] > > elif item == 0: > > raise IndexError, "Index 0 is not valid." > > else: > > raise IndexError, "Invalid Index." > > def __iter__(self): return iter(self.sequence) > > That final else clause is a little funny... What kind of indices are > you expecting that will be neither less than zero, greater than zero, > or equal to zero?
I'm not 'expecting' anything to reach that clause, but it is a good catch-all if I forget something or have a bug somewhere. > > Why the funny behavior, you ask? For my class A, it doesn't make sense > > to number everything the standard programming way. Of course, if > > someone uses enumerate, it's going to number the items the same way as > > ever. Is there any way to modify that behavior, any special function to > > set? There doesn't appear to be, according to the docs, but it never > > hurts to make sure. > > You can write your own enumerate function and then bind that to the > name 'enumerate'. Except that my program is supposed to be treated as a module with tools to do certain things. I certainly can't control whether a 3rd party programmer uses "import myModule" or "from myModule import *". I haven't gotten around to doing it yet, but I'm pretty sure I'm planning on taking Paul Rubin's course of action - make a method (iteritems or similar) that will enumerate correctly. -- http://mail.python.org/mailman/listinfo/python-list
