__index__ — Easy Examples

Returns an integer for use in slicing and bin()/hex()/oct()

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Implementing __index__

Basic implementation of __index__ in a class.

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

obj = Example()
print(obj)

__index__ returns an integer for use in slicing and bin()/hex()/oct(). Implementing it lets you customize how Python interacts with your objects.

__index__ in action

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

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

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

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

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

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