[Python-ideas] generator vs iterator etc. (was: How assignment should work with generators?)

Steven D'Aprano steve at pearwood.info
Mon Nov 27 18:44:49 EST 2017

On Mon, Nov 27, 2017 at 06:35:38PM +0200, Koos Zevenhoven wrote:

> SOLUTION: Maybe (a) all iterators should be called iterators 

All iterators *are* called iterators. Just as all mammals are called 

The subset of iterators which are created as generators are *also* 
called generators, just as the mammals which are dogs are called "dogs" 
when it is necessary to distinguish a dog from some other mammal.

> or (b) all
> iterators should be called generators, regardless of whether they are
> somehow a result of a generator function having been called in the past.

Absolutely not. That would be confusing -- it would be analogous to 
calling all sequences (lists, tuples, deques etc) "strings". What 
benefit is there to calling all iterators "generators", losing the 
distinction between those which are defined using def and yield and 
those created using iter()? Sometimes that distinction is important.

You are right that sometimes the term "generator" is used as shorthand 
for "generator function". Most of the time the distinction doesn't 
actually matter, since you cannot (easily?) create a generator without 
first creating a generator function. 

Or if it does matter, it is clear in context which is meant.

For those few times where it *does* matter, there is no substitute for 
precision in language, and that depends on the author, not the 


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