On Jan 31, 8:51 am, Csaba Hoch <csaba.h...@gmail.com> wrote: > What is the reason behind this difference between the __add__ operator > and int.__add__?
this is quite common in python. the special methods like __add__ are used to implement some functionality (like '+' in this case), but they are not all of it. for example, when a + b is evaluated, a.__add__(b) is attempted, but if that fails (raises a NotImplemented error) then b.__radd__(a) is tried instead. so there's not a 1-to-1 correspondence between '+' and __add__() and that is reflected in the exceptions, too. when a method does not exist a NotImplemented error is raised, but '+' contains extra logic and raises a more useful error message. does that make sense? i should probably add that this is just how i understand things - i assume it's correct, but i've not looked anything up in the documentation. andrew -- http://mail.python.org/mailman/listinfo/python-list
