/Doc/c-api/mapping.rst

 1.. highlightlang:: c
 2
 3.. _mapping:
 4
 5Mapping Protocol
 6================
 7
 8
 9.. cfunction:: int PyMapping_Check(PyObject *o)
10
11   Return ``1`` if the object provides mapping protocol, and ``0`` otherwise.  This
12   function always succeeds.
13
14
15.. cfunction:: Py_ssize_t PyMapping_Size(PyObject *o)
16               Py_ssize_t PyMapping_Length(PyObject *o)
17
18   .. index:: builtin: len
19
20   Returns the number of keys in object *o* on success, and ``-1`` on failure.  For
21   objects that do not provide mapping protocol, this is equivalent to the Python
22   expression ``len(o)``.
23
24   .. versionchanged:: 2.5
25      These functions returned an :ctype:`int` type. This might require
26      changes in your code for properly supporting 64-bit systems.
27
28
29.. cfunction:: int PyMapping_DelItemString(PyObject *o, char *key)
30
31   Remove the mapping for object *key* from the object *o*. Return ``-1`` on
32   failure.  This is equivalent to the Python statement ``del o[key]``.
33
34
35.. cfunction:: int PyMapping_DelItem(PyObject *o, PyObject *key)
36
37   Remove the mapping for object *key* from the object *o*. Return ``-1`` on
38   failure.  This is equivalent to the Python statement ``del o[key]``.
39
40
41.. cfunction:: int PyMapping_HasKeyString(PyObject *o, char *key)
42
43   On success, return ``1`` if the mapping object has the key *key* and ``0``
44   otherwise.  This is equivalent to ``o[key]``, returning ``True`` on success
45   and ``False`` on an exception.  This function always succeeds.
46
47
48.. cfunction:: int PyMapping_HasKey(PyObject *o, PyObject *key)
49
50   Return ``1`` if the mapping object has the key *key* and ``0`` otherwise.
51   This is equivalent to ``o[key]``, returning ``True`` on success and ``False``
52   on an exception.  This function always succeeds.
53
54
55.. cfunction:: PyObject* PyMapping_Keys(PyObject *o)
56
57   On success, return a list of the keys in object *o*.  On failure, return *NULL*.
58   This is equivalent to the Python expression ``o.keys()``.
59
60
61.. cfunction:: PyObject* PyMapping_Values(PyObject *o)
62
63   On success, return a list of the values in object *o*.  On failure, return
64   *NULL*. This is equivalent to the Python expression ``o.values()``.
65
66
67.. cfunction:: PyObject* PyMapping_Items(PyObject *o)
68
69   On success, return a list of the items in object *o*, where each item is a tuple
70   containing a key-value pair.  On failure, return *NULL*. This is equivalent to
71   the Python expression ``o.items()``.
72
73
74.. cfunction:: PyObject* PyMapping_GetItemString(PyObject *o, char *key)
75
76   Return element of *o* corresponding to the object *key* or *NULL* on failure.
77   This is the equivalent of the Python expression ``o[key]``.
78
79
80.. cfunction:: int PyMapping_SetItemString(PyObject *o, char *key, PyObject *v)
81
82   Map the object *key* to the value *v* in object *o*. Returns ``-1`` on failure.
83   This is the equivalent of the Python statement ``o[key] = v``.