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Dictionary Objects
PyDictObject
-
This subtype of
PyObject
represents a Python dictionary object.
- PyTypeObject
PyDict_Type
-
This instance of
PyTypeObject
represents the Python dictionary type. This is exposed to Python programs asdict
andtypes.DictType
.
-
int
PyDict_Check
( PyObject *p ) -
Return true if p is a dict object or an instance of a subtype of the dict type.
Changed in version 2.2: Allowed subtypes to be accepted.
-
int
PyDict_CheckExact
( PyObject *p ) -
Return true if p is a dict object, but not an instance of a subtype of the dict type.
New in version 2.4.
- PyObject*
PyDict_New
( ) - Return value: New reference.
Return a new empty dictionary, or NULL on failure.
- PyObject*
PyDictProxy_New
( PyObject *dict ) - Return value: New reference.
Return a proxy object for a mapping which enforces read-only behavior. This is normally used to create a proxy to prevent modification of the dictionary for non-dynamic class types.
New in version 2.2.
-
void
PyDict_Clear
( PyObject *p ) -
Empty an existing dictionary of all key-value pairs.
-
int
PyDict_Contains
( PyObject *p, PyObject *key ) -
Determine if dictionary p contains key. If an item in p is matches key, return
1
, otherwise return0
. On error, return-1
. This is equivalent to the Python expressionkey in p
.New in version 2.4.
- PyObject*
PyDict_Copy
( PyObject *p ) - Return value: New reference.
Return a new dictionary that contains the same key-value pairs as p.
New in version 1.6.
-
int
PyDict_SetItem
( PyObject *p, PyObject *key, PyObject *val ) -
Insert value into the dictionary p with a key of key. key must be hashable; if it isn’t,
TypeError
will be raised. Return0
on success or-1
on failure.
-
int
PyDict_SetItemString
( PyObject *p, const char *key, PyObject *val ) -
Insert value into the dictionary p using key as a key. key should be a
char*
. The key object is created usingPyString_FromString(key)
. Return0
on success or-1
on failure.
-
int
PyDict_DelItem
( PyObject *p, PyObject *key ) -
Remove the entry in dictionary p with key key. key must be hashable; if it isn’t,
TypeError
is raised. Return0
on success or-1
on failure.
-
int
PyDict_DelItemString
( PyObject *p, char *key ) -
Remove the entry in dictionary p which has a key specified by the string key. Return
0
on success or-1
on failure.
- PyObject*
PyDict_GetItem
( PyObject *p, PyObject *key ) - Return value: Borrowed reference.
Return the object from dictionary p which has a key key. Return NULL if the key key is not present, but without setting an exception.
- PyObject*
PyDict_GetItemString
( PyObject *p, const char *key ) - Return value: Borrowed reference.
This is the same as
PyDict_GetItem()
, but key is specified as achar*
, rather than aPyObject*
.
- PyObject*
PyDict_Items
( PyObject *p ) - Return value: New reference.
Return a
PyListObject
containing all the items from the dictionary, as in the dictionary methoddict.items()
.
- PyObject*
PyDict_Keys
( PyObject *p ) - Return value: New reference.
Return a
PyListObject
containing all the keys from the dictionary, as in the dictionary methoddict.keys()
.
- PyObject*
PyDict_Values
( PyObject *p ) - Return value: New reference.
Return a
PyListObject
containing all the values from the dictionary p, as in the dictionary methoddict.values()
.
-
Py_ssize_t
PyDict_Size
( PyObject *p ) -
Return the number of items in the dictionary. This is equivalent to
len(p)
on a dictionary.Changed in version 2.5: This function returned an
int
type. This might require changes in your code for properly supporting 64-bit systems.
-
int
PyDict_Next
( PyObject *p, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue ) -
Iterate over all key-value pairs in the dictionary p. The
Py_ssize_t
referred to by ppos must be initialized to0
prior to the first call to this function to start the iteration; the function returns true for each pair in the dictionary, and false once all pairs have been reported. The parameters pkey and pvalue should either point toPyObject*
variables that will be filled in with each key and value, respectively, or may be NULL. Any references returned through them are borrowed. ppos should not be altered during iteration. Its value represents offsets within the internal dictionary structure, and since the structure is sparse, the offsets are not consecutive.For example:
PyObject *key, *value; Py_ssize_t pos = 0; while (PyDict_Next(self->dict, &pos, &key, &value)) { /* do something interesting with the values... */ ... }
The dictionary p should not be mutated during iteration. It is safe (since Python 2.1) to modify the values of the keys as you iterate over the dictionary, but only so long as the set of keys does not change. For example:
PyObject *key, *value; Py_ssize_t pos = 0; while (PyDict_Next(self->dict, &pos, &key, &value)) { int i = PyInt_AS_LONG(value) + 1; PyObject *o = PyInt_FromLong(i); if (o == NULL) return -1; if (PyDict_SetItem(self->dict, key, o) < 0) { Py_DECREF(o); return -1; } Py_DECREF(o); }
Changed in version 2.5: This function used an
int *
type for ppos. This might require changes in your code for properly supporting 64-bit systems.
-
int
PyDict_Merge
( PyObject *a, PyObject *b, int override ) -
Iterate over mapping object b adding key-value pairs to dictionary a. b may be a dictionary, or any object supporting
PyMapping_Keys()
andPyObject_GetItem()
. If override is true, existing pairs in a will be replaced if a matching key is found in b, otherwise pairs will only be added if there is not a matching key in a. Return0
on success or-1
if an exception was raised.New in version 2.2.
-
int
PyDict_Update
( PyObject *a, PyObject *b ) -
This is the same as
PyDict_Merge(a, b, 1)
in C, and is similar toa.update(b)
in Python except thatPyDict_Update()
doesn’t fall back to the iterating over a sequence of key value pairs if the second argument has no “keys” attribute. Return0
on success or-1
if an exception was raised.New in version 2.2.
-
int
PyDict_MergeFromSeq2
( PyObject *a, PyObject *seq2, int override ) -
Update or merge into dictionary a, from the key-value pairs in seq2. seq2 must be an iterable object producing iterable objects of length 2, viewed as key-value pairs. In case of duplicate keys, the last wins if override is true, else the first wins. Return
0
on success or-1
if an exception was raised. Equivalent Python (except for the return value):def PyDict_MergeFromSeq2(a, seq2, override): for key, value in seq2: if override or key not in a: a[key] = value
New in version 2.2.