1 .. highlightlang:: c 2 3 .. _mapping: 4 5 Mapping Protocol 6 ================ 7 8 See also :c:func:`PyObject_GetItem`, :c:func:`PyObject_SetItem` and 9 :c:func:`PyObject_DelItem`. 10 11 12 .. c:function:: int PyMapping_Check(PyObject *o) 13 14 Return ``1`` if the object provides mapping protocol or supports slicing, 15 and ``0`` otherwise. Note that it returns ``1`` for Python classes with 16 a :meth:`__getitem__` method since in general case it is impossible to 17 determine what the type of keys it supports. This function always 18 succeeds. 19 20 21 .. c:function:: Py_ssize_t PyMapping_Size(PyObject *o) 22 Py_ssize_t PyMapping_Length(PyObject *o) 23 24 .. index:: builtin: len 25 26 Returns the number of keys in object *o* on success, and ``-1`` on failure. 27 This is equivalent to the Python expression ``len(o)``. 28 29 30 .. c:function:: PyObject* PyMapping_GetItemString(PyObject *o, const char *key) 31 32 Return element of *o* corresponding to the string *key* or *NULL* on failure. 33 This is the equivalent of the Python expression ``o[key]``. 34 See also :c:func:`PyObject_GetItem`. 35 36 37 .. c:function:: int PyMapping_SetItemString(PyObject *o, const char *key, PyObject *v) 38 39 Map the string *key* to the value *v* in object *o*. Returns ``-1`` on 40 failure. This is the equivalent of the Python statement ``o[key] = v``. 41 See also :c:func:`PyObject_SetItem`. 42 43 44 .. c:function:: int PyMapping_DelItem(PyObject *o, PyObject *key) 45 46 Remove the mapping for the object *key* from the object *o*. Return ``-1`` 47 on failure. This is equivalent to the Python statement ``del o[key]``. 48 This is an alias of :c:func:`PyObject_DelItem`. 49 50 51 .. c:function:: int PyMapping_DelItemString(PyObject *o, const char *key) 52 53 Remove the mapping for the string *key* from the object *o*. Return ``-1`` 54 on failure. This is equivalent to the Python statement ``del o[key]``. 55 56 57 .. c:function:: int PyMapping_HasKey(PyObject *o, PyObject *key) 58 59 Return ``1`` if the mapping object has the key *key* and ``0`` otherwise. 60 This is equivalent to the Python expression ``key in o``. 61 This function always succeeds. 62 63 Note that exceptions which occur while calling the :meth:`__getitem__` 64 method will get suppressed. 65 To get error reporting use :c:func:`PyObject_GetItem()` instead. 66 67 68 .. c:function:: int PyMapping_HasKeyString(PyObject *o, const char *key) 69 70 Return ``1`` if the mapping object has the key *key* and ``0`` otherwise. 71 This is equivalent to the Python expression ``key in o``. 72 This function always succeeds. 73 74 Note that exceptions which occur while calling the :meth:`__getitem__` 75 method and creating a temporary string object will get suppressed. 76 To get error reporting use :c:func:`PyMapping_GetItemString()` instead. 77 78 79 .. c:function:: PyObject* PyMapping_Keys(PyObject *o) 80 81 On success, return a list of the keys in object *o*. On failure, return 82 *NULL*. 83 84 .. versionchanged:: 3.7 85 Previously, the function returned a list or a tuple. 86 87 88 .. c:function:: PyObject* PyMapping_Values(PyObject *o) 89 90 On success, return a list of the values in object *o*. On failure, return 91 *NULL*. 92 93 .. versionchanged:: 3.7 94 Previously, the function returned a list or a tuple. 95 96 97 .. c:function:: PyObject* PyMapping_Items(PyObject *o) 98 99 On success, return a list of the items in object *o*, where each item is a 100 tuple containing a key-value pair. On failure, return *NULL*. 101 102 .. versionchanged:: 3.7 103 Previously, the function returned a list or a tuple. 104
