Special Methods Table

This table lists all of the special methods together with their parameter and return types. In the table below, a parameter name of self is used to indicate that the parameter has the type that the method belongs to. Other parameters with no type specified in the table are generic Python objects.

You don’t have to declare your method as taking these parameter types. If you declare different types, conversions will be performed as necessary.

General

Name Parameters Return type Description
__cinit__ self, ...   Basic initialisation (no direct Python equivalent)
__init__ self, ...   Further initialisation
__dealloc__ self   Basic deallocation (no direct Python equivalent)
__cmp__ x, y int 3-way comparison
__richcmp__ x, y, int op object Rich comparison (no direct Python equivalent)
__str__ self object str(self)
__repr__ self object repr(self)
__hash__ self int Hash function
__call__ self, ... object self(...)
__iter__ self object Return iterator for sequence
__getattr__ self, name object Get attribute
__getattribute__ self, name object Get attribute, unconditionally
__setattr__ self, name, val   Set attribute
__delattr__ self, name   Delete attribute

Arithmetic operators

Name Parameters Return type Description
__add__ x, y object binary + operator
__sub__ x, y object binary - operator
__mul__ x, y object * operator
__div__ x, y object / operator for old-style division
__floordiv__ x, y object // operator
__truediv__ x, y object / operator for new-style division
__mod__ x, y object % operator
__divmod__ x, y object combined div and mod
__pow__ x, y, z object ** operator or pow(x, y, z)
__neg__ self object unary - operator
__pos__ self object unary + operator
__abs__ self object absolute value
__nonzero__ self int convert to boolean
__invert__ self object ~ operator
__lshift__ x, y object << operator
__rshift__ x, y object >> operator
__and__ x, y object & operator
__or__ x, y object | operator
__xor__ x, y object ^ operator

Numeric conversions

Name Parameters Return type Description
__int__ self object Convert to integer
__long__ self object Convert to long integer
__float__ self object Convert to float
__oct__ self object Convert to octal
__hex__ self object Convert to hexadecimal
__index__ self object Convert to sequence index

In-place arithmetic operators

Name Parameters Return type Description
__iadd__ self, x object += operator
__isub__ self, x object -= operator
__imul__ self, x object *= operator
__idiv__ self, x object /= operator for old-style division
__ifloordiv__ self, x object //= operator
__itruediv__ self, x object /= operator for new-style division
__imod__ self, x object %= operator
__ipow__ x, y, z object **= operator
__ilshift__ self, x object <<= operator
__irshift__ self, x object >>= operator
__iand__ self, x object &= operator
__ior__ self, x object |= operator
__ixor__ self, x object ^= operator

Sequences and mappings

Name Parameters Return type Description
__len__ self int   len(self)
__getitem__ self, x object self[x]
__setitem__ self, x, y   self[x] = y
__delitem__ self, x   del self[x]
__getslice__ self, Py_ssize_t i, Py_ssize_t j object self[i:j]
__setslice__ self, Py_ssize_t i, Py_ssize_t j, x   self[i:j] = x
__delslice__ self, Py_ssize_t i, Py_ssize_t j   del self[i:j]
__contains__ self, x int x in self

Iterators

Name Parameters Return type Description
__next__ self object Get next item (called next in Python)

Buffer interface

Note

The buffer interface is intended for use by C code and is not directly accessible from Python. It is described in the Python/C API Reference Manual under sections 6.6 and 10.6.

Name Parameters Return type Description
__getreadbuffer__ self, int i, void **p    
__getwritebuffer__ self, int i, void **p    
__getsegcount__ self, int *p    
__getcharbuffer__ self, int i, char **p    

Descriptor objects

Note

Descriptor objects are part of the support mechanism for new-style Python classes. See the discussion of descriptors in the Python documentation. See also PEP 252, “Making Types Look More Like Classes”, and PEP 253, “Subtyping Built-In Types”.

Name Parameters Return type Description
__get__ self, instance, class object Get value of attribute
__set__ self, instance, value   Set value of attribute
__delete__ self, instance   Delete attribute