__neg__ — Easy Examples

Defines behavior for the unary - negation operator

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Implementing __neg__

Basic implementation of __neg__ in a class.

python
class Example:
    def __neg__(self):
        return "Example __neg__"

obj = Example()
print(obj)

__neg__ defines behavior for the unary - negation operator. Implementing it lets you customize how Python interacts with your objects.

__neg__ in action

Seeing __neg__ called by Python's built-in operations.

python
# How Python calls __neg__ automatically
class Demo:
    def __init__(self, value):
        self.value = value

    def __neg__(self):
        print(f"__neg__ was called!")
        return self

d = Demo(42)
# This triggers __neg__:
print(d)

Python automatically calls __neg__ when you use the corresponding operator or function on your object.

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