Differentiate False and 0

Question

Let's say I have a list with different values, like this:

[1,2,3,'b', None, False, True, 7.0]

I want to iterate over it and check that every element is not in list of some forbidden values. For example, this list is [0,0.0].

When I check if False in [0,0.0] I get True. I understand that python casts False to 0 here - but how I can avoid it and make this check right - that False value is not in [0,0.0]?

Answer 1

To tell the difference between False and 0 you may use is to compare them. False is a singleton value and always refers to the same object. To compare all the items in a list to make sure they are not False, try:

all(x is not False for x in a_list)

BTW, Python doesn't cast anything here: Booleans are a subclass of integers, and False is literally equal to 0, no conversion required.

Answer 2

You would want to use is instead of == when comparing.

y = 0
print y == False # True
print y is False # False

x = False
print x == False # True
print x is False # True