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__ (2.5+ only) | 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 |