1 .. highlightlang:: c

     2 

     3 .. _mapping:

     4 

     5 Mapping 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_Length(PyObject *o)

    16 

    17    .. index:: builtin: len

    18 

    19    Returns the number of keys in object *o* on success, and ``-1`` on failure.  For

    20    objects that do not provide mapping protocol, this is equivalent to the Python

    21    expression ``len(o)``.

    22 

    23 

    24 .. cfunction:: int PyMapping_DelItemString(PyObject *o, char *key)

    25 

    26    Remove the mapping for object *key* from the object *o*. Return ``-1`` on

    27    failure.  This is equivalent to the Python statement ``del o[key]``.

    28 

    29 

    30 .. cfunction:: int PyMapping_DelItem(PyObject *o, PyObject *key)

    31 

    32    Remove the mapping for object *key* from the object *o*. Return ``-1`` on

    33    failure.  This is equivalent to the Python statement ``del o[key]``.

    34 

    35 

    36 .. cfunction:: int PyMapping_HasKeyString(PyObject *o, char *key)

    37 

    38    On success, return ``1`` if the mapping object has the key *key* and ``0``

    39    otherwise.  This is equivalent to ``o[key]``, returning ``True`` on success

    40    and ``False`` on an exception.  This function always succeeds.

    41 

    42 

    43 .. cfunction:: int PyMapping_HasKey(PyObject *o, PyObject *key)

    44 

    45    Return ``1`` if the mapping object has the key *key* and ``0`` otherwise.

    46    This is equivalent to ``o[key]``, returning ``True`` on success and ``False``

    47    on an exception.  This function always succeeds.

    48 

    49 

    50 .. cfunction:: PyObject* PyMapping_Keys(PyObject *o)

    51 

    52    On success, return a list of the keys in object *o*.  On failure, return *NULL*.

    53    This is equivalent to the Python expression ``o.keys()``.

    54 

    55 

    56 .. cfunction:: PyObject* PyMapping_Values(PyObject *o)

    57 

    58    On success, return a list of the values in object *o*.  On failure, return

    59    *NULL*. This is equivalent to the Python expression ``o.values()``.

    60 

    61 

    62 .. cfunction:: PyObject* PyMapping_Items(PyObject *o)

    63 

    64    On success, return a list of the items in object *o*, where each item is a tuple

    65    containing a key-value pair.  On failure, return *NULL*. This is equivalent to

    66    the Python expression ``o.items()``.

    67 

    68 

    69 .. cfunction:: PyObject* PyMapping_GetItemString(PyObject *o, char *key)

    70 

    71    Return element of *o* corresponding to the object *key* or *NULL* on failure.

    72    This is the equivalent of the Python expression ``o[key]``.

    73 

    74 

    75 .. cfunction:: int PyMapping_SetItemString(PyObject *o, char *key, PyObject *v)

    76 

    77    Map the object *key* to the value *v* in object *o*. Returns ``-1`` on failure.

    78    This is the equivalent of the Python statement ``o[key] = v``.