I’m trying to understand the difference between iterator and generator. I read that “Every generator is an iterator, but not vice versa.”
Could someone give an example of an object that IS an iterator, but IS NOT a generator?
I mean, if an object has method next (which is the definition of an iterator), we can also call it a generator, can’t we?
UPD: for those who say that generator must have yield – not always. (i**2 for i in range(1,5)) doesn’t have yield and is also a generator.
For those who say that iter([1,2,3]) is not a generator – why? Which definition of a generator it contradicts and where?
“Every generator is an iterator, but not vice versa.”
I don’t think that’s necessarily true. The Python glossary gives 3 entries that start with “generator”.
This is any function with a
yield statement. A generator function is not an iterator, but it does return an iterator when you call it.
def getSquares(n): for i in range(n): yield i**2
This is the thing that gets returned by a generator function.
This is just a comprehension inside parentheses.
(i**2 for i in range(10))
Generator expressions and the return values of generator functions both give
<class 'generator'> when you call
type on them. However, if you define your own class with a
__next__ method, its instances will, of course, have that class as their