Iterator for Custom Sequence

[Patrick W]

Jonathan Hogg <jonathan at onegoodidea.com> writes:

> I'm not sure why you've used a nested function. 

Relic of an early misunderstanding.

At first I thought __iter__ was supposed to *return* a generator, so I
made it a nested function and handed it to the caller. When that
didn't work, I made __iter__ *call* the nested generator. I should
then have realised that __iter__ could *be* the generator, but for
some reason I didn't.

(Instead I was off chasing red herrings, wondering whether the
generator ought to be a nested function, class method or free
function. Ridiculous in hindsight, but such is life).

> I would have written this simply as:
> 
>     class LinkedList:
>         ....
>         def __iter__(self):
>             node = self.head
>             while node.next is not None:
>                 yield node.data
>                 node = node.next
>         ....

That's lovely. Thanks.