all Python 3Built-in typesterm

False

special values

Boolean falsehood, the other instance of bool, equal to 0. 0, '', [] and None are falsy too, but only zeros equal False.

Syntax

False

False is a built-in constant you cannot assign to; as an int subclass it equals 0 and is the same dict key as 0. The main trap is mixing up "falsy" and "equal to False": [] == False and None == False are both False, even though both values are falsy in an if. Test emptiness with if not x:, a missing value with x is None, and treat x == False as almost always a bug.

Examples

print(False == 0, False + 1)   # → True 1
print(bool([]), [] == False)   # → False False — ложно, но не равно False
print(None == False, not None)   # → False True

d = {0: 'ноль'}
d[False] = 'ложь'   # тот же ключ, что и 0
print(d)   # → {0: 'ложь'}

See also

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