all Python 3operatorfunction

operator.neg

arithmetic

Return −a (unary negation).

Syntax

operator.neg(a)

It works as a descending sort key for numbers: sorted(xs, key=operator.neg). That does not work for strings — use reverse=True there. Floats keep the sign even for zero: neg(0.0) gives -0.0, visible when printed and through math.copysign. A user class supports neg by defining __neg__.

Examples

import operator
print(operator.neg(3))   # → -3
print(operator.neg(3) == -3)   # → True
print(list(map(operator.neg, [1, -2, 3])))   # → [-1, 2, -3]
print(sorted([3, 1, 2], key=operator.neg))   # → [3, 2, 1]
print(operator.neg(True))   # → -1

See also

Common errors

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