0
0
mirror of https://github.com/python/cpython.git synced 2024-11-27 23:47:29 +01:00
cpython/Doc/c-api/mapping.rst
Jelle Zijlstra 11f5fd1135
[3.10] More minor fixes to C API docs (GH-31525) (GH-32258)
* wording fixes in type.rst

* grammar and punctuation in sys.rst

* set: grammar fixes

* structures: capitalization fix

* grammar fixes for sequence

* objects: point to Py_TYPE instead of direct object access

* numbers: add more explicit Python equivalences

* method: add missing period

* memory: grammar fix

* mapping: grammar fixes

* long: grammar fix

* iter: fix grammar for PyAIter_Check

* init: grammar fix.
(cherry picked from commit 897bc6f928)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
2022-04-02 16:00:51 -07:00

104 lines
3.5 KiB
ReStructuredText

.. highlight:: c
.. _mapping:
Mapping Protocol
================
See also :c:func:`PyObject_GetItem`, :c:func:`PyObject_SetItem` and
:c:func:`PyObject_DelItem`.
.. c:function:: int PyMapping_Check(PyObject *o)
Return ``1`` if the object provides the mapping protocol or supports slicing,
and ``0`` otherwise. Note that it returns ``1`` for Python classes with
a :meth:`__getitem__` method, since in general it is impossible to
determine what type of keys the class supports. This function always succeeds.
.. c:function:: Py_ssize_t PyMapping_Size(PyObject *o)
Py_ssize_t PyMapping_Length(PyObject *o)
.. index:: builtin: len
Returns the number of keys in object *o* on success, and ``-1`` on failure.
This is equivalent to the Python expression ``len(o)``.
.. c:function:: PyObject* PyMapping_GetItemString(PyObject *o, const char *key)
Return element of *o* corresponding to the string *key* or ``NULL`` on failure.
This is the equivalent of the Python expression ``o[key]``.
See also :c:func:`PyObject_GetItem`.
.. c:function:: int PyMapping_SetItemString(PyObject *o, const char *key, PyObject *v)
Map the string *key* to the value *v* in object *o*. Returns ``-1`` on
failure. This is the equivalent of the Python statement ``o[key] = v``.
See also :c:func:`PyObject_SetItem`. This function *does not* steal a
reference to *v*.
.. c:function:: int PyMapping_DelItem(PyObject *o, PyObject *key)
Remove the mapping for the object *key* from the object *o*. Return ``-1``
on failure. This is equivalent to the Python statement ``del o[key]``.
This is an alias of :c:func:`PyObject_DelItem`.
.. c:function:: int PyMapping_DelItemString(PyObject *o, const char *key)
Remove the mapping for the string *key* from the object *o*. Return ``-1``
on failure. This is equivalent to the Python statement ``del o[key]``.
.. c:function:: int PyMapping_HasKey(PyObject *o, PyObject *key)
Return ``1`` if the mapping object has the key *key* and ``0`` otherwise.
This is equivalent to the Python expression ``key in o``.
This function always succeeds.
Note that exceptions which occur while calling the :meth:`__getitem__`
method will get suppressed.
To get error reporting use :c:func:`PyObject_GetItem()` instead.
.. c:function:: int PyMapping_HasKeyString(PyObject *o, const char *key)
Return ``1`` if the mapping object has the key *key* and ``0`` otherwise.
This is equivalent to the Python expression ``key in o``.
This function always succeeds.
Note that exceptions which occur while calling the :meth:`__getitem__`
method and creating a temporary string object will get suppressed.
To get error reporting use :c:func:`PyMapping_GetItemString()` instead.
.. c:function:: PyObject* PyMapping_Keys(PyObject *o)
On success, return a list of the keys in object *o*. On failure, return
``NULL``.
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.
.. c:function:: PyObject* PyMapping_Values(PyObject *o)
On success, return a list of the values in object *o*. On failure, return
``NULL``.
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.
.. c:function:: PyObject* PyMapping_Items(PyObject *o)
On success, return a list of the items in object *o*, where each item is a
tuple containing a key-value pair. On failure, return ``NULL``.
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.