Stefan Behnel ha scritto:
Hi,
I just had a discussion with a co-worker, and we noticed that there are use cases where you just want the only element in a data structure, or just any of the elements in a data structure because you know that they all contain the same information (with respect to what you are looking for, at least).
If you want all items, you can iterate, but if you just want any item or the only item, it's inefficient (and not very explicit code) to create an iterator and take the element out. It's easy to do with ordered data structures such as lists or tuples ("container[0]"), but it's not so obvious for sets (or dicts), which means that you have to know what kind of container you receive to handle it correctly. I know there's .pop() on sets, but that modifies the data structure.
You can do next(iter(container)) (or iter(container).next() with python <= 2.5). This works fine with any iterable. matteo