all Python 3operatorfunction

operator.is_

identity and logic

Identity test: a is b (the very same object in memory).

Syntax

operator.is_(a, b)

It compares objects, not values, so it suits None, sentinel singletons and checks like "is this the same list, not a copy". For numbers and strings the result depends on interpreter caching: is_(256, 256) is usually true, but not for large numbers or built-up strings. Compare values with eq.

Examples

import operator
x = []
print(operator.is_(x, x))   # → True
y = []
print(operator.is_(x, y))   # → False
print(operator.eq(x, y))   # → True
values = [None, 0, None]
print([operator.is_(v, None) for v in values])   # → [True, False, True]
print(operator.is_(True, 1))   # → False

See also

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