[Python-ideas] Consider making enumerate a sequence if its argument is a sequence

[Akira Li]

Random832 <random832 at fastmail.com> writes:

> Akira Li <4kir4.1i at gmail.com> writes:
>
>> Andrew Barnert via Python-ideas
>> <python-ideas at python.org> writes:
>> ...
>>> (The fact that we don't have a term for "non-iterator iterable", and
>>
>> All iterators are iterable but some iterables are not iterators.
>>
>> If your code accepts only iterators then use the term *iterator*.
>> Otherwise the term *iterable* could be used.
>>
>> It is misleading to use *iterable* if your code only accepts iterators.
>>
>> If an iterable is an iterator; It is called *iterator*. The term
>> *iterable* implies that some instances are not iterators.
>
> There are three (well, three and a half) kinds of code that consume
> iterables, how would you describe each simply?
>
> 1. Does not call iter, simply calls next. Therefore cannot consume a
>    non-iterator iterable.
iterator

> 2. Calls iter, but can accept an iterator (e.g. only goes through it
>    once)
iterable

> 3. Cannot accept an iterator (goes through it twice, or permanently
>    stores a reference to it, etc)
neither

*iterable* is an object that you can pass to iter() to get *iterator*.
An iterable does not guarantee that it yields the same items twice.

> 4. Can accept either, but behaves differently in each case (e.g. zip
>    when passed two of the same iterator) - this can be regarded as a
>    special case of #2.
iterable