Please some one explain this what iterator is j

Question

smart_multiples = {i: [j for j in range(20) if not j % i] for i in range(2, 10)}
print(smart_multiples

Answer 1

That's a comprehension creating an iterable.

You might wanna read this:

https://code.sololearn.com/ck6HicJ6Z8jG/?ref=app

Answer 2

Nidified comprehension, to be exact.

The outer one {} is a dictionary comprehension, which generates 8 couples key -> list of multiples of the key. The 8 list of multiples are generated by 8 list comprehensions []