Fix Python – Why does “not(True) in [False, True]” return False?

Question

Asked By – Texom512

If I do this:

>>> False in [False, True]
True

That returns True. Simply because False is in the list.

But if I do:

>>> not(True) in [False, True]
False

That returns False. Whereas not(True) is equal to False:

>>> not(True)
False

Why?

Now we will see solution for issue: Why does “not(True) in [False, True]” return False?


Answer

Operator precedence 2.x, 3.x. The precedence of not is lower than that of in. So it is equivalent to:

>>> not ((True) in [False, True])
False

This is what you want:

>>> (not True) in [False, True]
True

As @Ben points out: It’s recommended to never write not(True), prefer not True. The former makes it look like a function call, while not is an operator, not a function.

This question is answered By – Yu Hao

This answer is collected from stackoverflow and reviewed by FixPython community admins, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0