26.3. Special method names

Within a class, a number of reserved method names have special meaning. Here is a list of the ones covered in this document.

`__abs__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__add__`	Section 26.3.2, “Special methods for binary operators”
`__and__`	Section 26.3.2, “Special methods for binary operators”
`__call__`	Section 26.3.5, “`__call__()`: What to do when someone calls an instance”
`__cmp__`	Section 26.3.6, “`__cmp__()`: Generalized comparison”
`__complex__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__contains__`	Section 26.3.7, “`__contains__()`: The “`in`” and “`not in`” operators”
`__del__`	Section 26.3.8, “`__del__()`: Destructor”
`__delattr__`	Section 26.3.9, “`__delattr__()`: Delete an attribute”
`__delitem__`	Section 26.3.10, “`__delitem__()`: Delete one item of a sequence”
`__divmod__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__div__`	Section 26.3.2, “Special methods for binary operators”
`__divmod__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__enter__`	Section 26.3.11, “`__enter__`: Context manager initialization”
`__exit__`	Section 26.3.12, “`__exit__`: Context manager cleanup”
`__eq__`	Section 26.3.1, “Rich comparison methods”
`__floordiv__`	Section 26.3.2, “Special methods for binary operators”
`__float__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__ge__`	Section 26.3.1, “Rich comparison methods”
`__getattr__`	Section 26.3.14, “`__getattr__()`: Handle a reference to an unknown attribute”
`__getattribute__`	Section 26.3.15, “`__getattribute__()`: Intercept all attribute references”
`__getitem__`	Section 26.3.16, “`__getitem__()`: Get one item from a sequence or mapping”
`__gt__`	Section 26.3.1, “Rich comparison methods”
`__hex__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__iadd__`	Section 26.3.2, “Special methods for binary operators”
`__iand__`	Section 26.3.2, “Special methods for binary operators”
`__idiv__`	Section 26.3.2, “Special methods for binary operators”
`__ifloordiv__`	Section 26.3.2, “Special methods for binary operators”
`__ilshift__`	Section 26.3.2, “Special methods for binary operators”
`__imod__`	Section 26.3.2, “Special methods for binary operators”
`__imul__`	Section 26.3.2, “Special methods for binary operators”
`__init__`	Section 26, “Classes: Defining your own types”
`__int__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__invert__`	Section 26.3.3, “Unary operator special methods”
`__ior__`	Section 26.3.2, “Special methods for binary operators”
`__ipow__`	Section 26.3.2, “Special methods for binary operators”
`__irshift__`	Section 26.3.2, “Special methods for binary operators”
`__isub__`	Section 26.3.2, “Special methods for binary operators”
`__iter__`	Section 26.3.17, “`__iter__()`: Create an iterator”
`__ixor__`	Section 26.3.2, “Special methods for binary operators”
`__le__`	Section 26.3.1, “Rich comparison methods”
`__len__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__long__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__lshift__`	Section 26.3.2, “Special methods for binary operators”
`__lt__`	Section 26.3.1, “Rich comparison methods”
`__mod__`	Section 26.3.2, “Special methods for binary operators”
`__mul__`	Section 26.3.2, “Special methods for binary operators”
`__ne__`	Section 26.3.1, “Rich comparison methods”
`__neg__`	Section 26.3.3, “Unary operator special methods”
`__new__`	Section 26.2.1, “`__new__()`: New instance creation”
`__nonzero__`	Section 26.3.18, “`__nonzero__()`: True/false evaluation”
`__oct__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__or__`	Section 26.3.2, “Special methods for binary operators”
`__pos__`	Section 26.3.3, “Unary operator special methods”
`__pow__`	Section 26.3.2, “Special methods for binary operators”
`__radd__`	Section 26.3.2, “Special methods for binary operators”
`__rand__`	Section 26.3.2, “Special methods for binary operators”
`__rdiv__`	Section 26.3.2, “Special methods for binary operators”
`__repr__`	Section 26.3.19, “`__repr__()`: String representation”
`__reversed__`	Section 26.3.20, “`__reversed__()`: Implement the `reversed()` function”
`__rfloordiv__`	Section 26.3.2, “Special methods for binary operators”
`__rlshift__`	Section 26.3.2, “Special methods for binary operators”
`__rmod__`	Section 26.3.2, “Special methods for binary operators”
`__rmul__`	Section 26.3.2, “Special methods for binary operators”
`__ror__`	Section 26.3.2, “Special methods for binary operators”
`__rpow__`	Section 26.3.2, “Special methods for binary operators”
`__rrshift__`	Section 26.3.2, “Special methods for binary operators”
`__rshift__`	Section 26.3.2, “Special methods for binary operators”
`__rsub__`	Section 26.3.2, “Special methods for binary operators”
`__rxor__`	Section 26.3.2, “Special methods for binary operators”
`__setattr__`	Section 26.3.21, “`__setattr__()`: Intercept all attribute changes”
`__setitem__`	Section 26.3.22, “`__setitem__()`: Assign a value to one item of a sequence”
`__str__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__sub__`	Section 26.3.2, “Special methods for binary operators”
`__unicode__`	Section 26.3.4, “Special methods to emulate built-in functions”
`__xor__`	Section 26.3.2, “Special methods for binary operators”

The most important special method name is the class constructor, .__init__().

For a general introduction to class constructors, see Section 26, “Classes: Defining your own types”.
For old-style class constructors, see Section 26.1.2, “Instantiation of an old-style class: The constructor, .__init__()”.
For new-style class constructors, see Section 26.2, “Life cycle of a new-style class”.

Many special methods fall into broad categories:

Section 26.3.1, “Rich comparison methods”: for methods that implement comparisons such as “<=” and “==”.
Section 26.3.2, “Special methods for binary operators”: for operators that operate on two operands, such as “%”.
Section 26.3.3, “Unary operator special methods”: for operators that operate on a single operand, such as negation, “-”.
Section 26.3.4, “Special methods to emulate built-in functions”: for classes that handle calls to built-in functions such as “str()”.

Python 2.7 quick reference

26.3. Special method names