How does this class implement the “__iter__” method without implementing “next”?

Question

I have the following code in django.template:

class Template(object):
    def __init__(self, template_string, origin=None, name=\'\'):
           


        

Answer 1

That __iter__method returns a python generator (see the documentation), as it uses the yield keyword. The generator will provide the next() method automatically; quoting the documentation:

What makes generators so compact is that the __iter__() and next() methods are created automatically.

EDIT:

Generators are really useful. If you are not familiar with them, I suggest you readup on them, and play around with some test code.

Here is some more info on iterators and generators from StackOverflow.