Question

I’m implementing what is essentially a container object (although it does have a little of it’s own logic). I want to be able to iterate over items in a field in this class (which is just a plain list). Should I re-implement __iter__ and next for my class or is it acceptable to return the iterator of the list, like so:

class X:

    def __init__(self):
       self.list = []

    def __iter__(self):
        return self.list.__iter__()

I’m a little unsure if this will lead to any undesirable behavior.

Answer 1

It is fine to use the iterator of the built-in list type. I’d suggest not to call __iter__() explicitly, though, but rather use the built-in function iter():

def __iter__(self):
    return iter(self.list)

Another option might be to derive X from list. (In Python 2.x, you should at least derive from object.)