freeCodeCamp/guide/english/python/boolean-operations/index.md

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Python Boolean Operations

or, and, not

Python Docs - Boolean Operations

These are the Boolean operations, ordered by ascending priority:

Operation	Result	Notes
x or y	if x is false, then y, else x	(1)
x and y	if x is false, then x, else y	(2)
not x	if x is false, then True, else False	(3)

Notes:

1. This is a short-circuit operator, so it only evaluates the second argument if the first one is False.
2. This is a short-circuit operator, so it only evaluates the second argument if the first one is True.
3. not has a lower priority than non-Boolean operators, so not a == b is interpreted as not (a == b), and a == not b is a syntax error.

Examples:

or:

>>> True or False    # Short-circuited at first argument.
True
>>> False or True    # Second argument is evaluated.
True
>>> False or False   # Second argument is evaluated.
False

and:

>>> True and False    # Second argument is evaluated.
False
>>> False and True    # Short-circuted at first argument.
False
>>> True and True     # Second argument is evaluated.
True

not:

>>> not True
False
>>> not False
True
>>> False or False   # Second argument is evaluated.
False