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ast.NotIn

operators

The not in membership operator in the ops list of a Compare node.

Syntax

ast.NotIn()

Although it is written as two words, it is one operator: a not in b gives a Compare with a single NotIn, with no UnaryOp or Not. Likewise is not is IsNot. Code that hunts for negation via ast.Not misses not in, whereas not a in b, with the same meaning, does produce UnaryOp(Not, Compare(In)).

Examples

import ast
n = ast.parse('x not in seen', mode='eval').body
print(type(n).__name__, [type(o).__name__ for o in n.ops])  # → Compare ['NotIn']
print(any(isinstance(m, ast.Not) for m in ast.walk(n)))  # → False

See also

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