Question

I would like to know why this is valid:

set(range(10)) - set(range(5))

but this is not valid:

set(range(10)) + set(range(5))

Is it because ‘+’ could mean both intersection and union?

Answer 1

Python sets don’t have an implementation for the + operator.

You can use | for set union and & for set intersection.

Sets do implement - as set difference. You can also use ^ for symmetric set difference (i.e., it will return a new set with only the objects that appear in one set but do not appear in both sets).