This would be useful for libraries like tqdm (progress bar module).

same for itertools iterators -  libraries such as tqdm would benefit from
this

On Sat, Jul 16, 2016 at 3:08 PM, James Lu <report@bugs.python.org> wrote:

>
> New submission from James Lu:
>
> This would be useful for libraries like tqdm (progress bar module).
>
> ----------
> components: Interpreter Core
> messages: 270581
> nosy: James.Lu
> priority: normal
> severity: normal
> status: open
> title: Dictionary iterator has no len()
> type: enhancement
> versions: Python 3.6
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue27532>
> _______________________________________
>

If you read issue 24849, you will see that iterators having len was rejected by Guido long ago.

I think you closed it too quickly. You see, computing the length of
combinations() doesn't require looping all the way through the iterator;
you can compute it quickly. I created a wrapper class just for this purpose.

On Sat, Jul 16, 2016 at 5:24 PM, R. David Murray <report@bugs.python.org>
wrote:

>
> R. David Murray added the comment:
>
> If you read issue 24849, you will see that iterators having len was
> rejected by Guido long ago.
>
> ----------
> nosy: +r.david.murray
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue27532>
> _______________________________________
>

Please read the referenced issue.  Your points are addressed there.