How does Python process a statement with both assignment and a comparison?

Question

I've got the following line:

group_index = apps["special_groups"] == group

From my understanding, group_index is being assigned the value in apps["special_groups"]. Then I see the == operator, but what does it do with the result? Or is it comparing apps["special_groups"] to group first?

Answer 1

From the Python docs, Section 5.14:

Python evaluates expressions from left to right. Notice that while evaluating an assignment, the right-hand side is evaluated before the left-hand side.

Therefore it evaluates the right-hand side, apps["special_groups"] == group, first, and then it assigns this result to the left-hand side, group_index.

Answer 2

From the Python Evaluation Order documentation:

Notice that while evaluating an assignment, the right-hand side is evaluated before the left-hand side.

So it first evaluates apps["special_groups"] == group, then assigns the result of this to group_index.

Answer 3

It assigns the value of the boolean comparison [True or False] to the LHS variable group_index.