typePyDictObject
This subtype of
represents a Python dictionary object.
PyDict_Type
Part of the
.This instance of
represents the Python dictionary type. This is the same object as
in the Python layer.
intPyDict_Check(
*p)
Thread safety:
.Return true if p is a dict object or an instance of a subtype of the dict type. This function always succeeds.
intPyDict_CheckExact(
*p)
Thread safety:
.Return true if p is a dict object, but not an instance of a subtype of the dict type. This function always succeeds.
*PyDict_New()
Return value: New reference. Part of the
. Thread safety:
.Return a new empty dictionary, or NULL on failure.
*PyDictProxy_New(
*mapping)
Return value: New reference. Part of the
.Return a
object for a mapping which enforces read-only behavior. This is normally used to create a view to prevent modification of the dictionary for non-dynamic class types.
PyDictProxy_Type
Part of the
.The type object for mapping proxy objects created by
and for the read-only __dict__ attribute of many built-in types. A
instance provides a dynamic, read-only view of an underlying dictionary: changes to the underlying dictionary are reflected in the proxy, but the proxy itself does not support mutation operations. This corresponds to
in Python.
voidPyDict_Clear(
*p)
Part of the
. Thread safety:
.Empty an existing dictionary of all key-value pairs.
intPyDict_Contains(
*p,
*key)
Part of the
. Thread safety:
Safe for concurrent use on the same object
.Determine if dictionary p contains key. If an item in p matches key, return 1, otherwise return 0. On error, return -1. This is equivalent to the Python expression keyinp.
intPyDict_ContainsString(
*p, constchar*key)
Thread safety:
.This is the same as
, but key is specified as a constchar* UTF-8 encoded bytes string, rather than a
*.
Added in version 3.13.
*PyDict_Copy(
*p)
Return value: New reference. Part of the
. Thread safety:
.Return a new dictionary that contains the same key-value pairs as p.
intPyDict_SetItem(
*p,
*key,
*val)
Part of the
. Thread safety:
Safe for concurrent use on the same object
.Insert val into the dictionary p with a key of key. key must be
; if it isn’t,
will be raised. Return 0 on success or -1 on failure. This function does not “
” a reference to val.
intPyDict_SetItemString(
*p, constchar*key,
*val)
Part of the
. Thread safety:
.This is the same as
, but key is specified as a constchar* UTF-8 encoded bytes string, rather than a
*.
intPyDict_DelItem(
*p,
*key)
Part of the
. Thread safety:
Safe for concurrent use on the same object
.Remove the entry in dictionary p with key key. key must be
; if it isn’t,
is raised. If key is not in the dictionary,
is raised. Return 0 on success or -1 on failure.
intPyDict_DelItemString(
*p, constchar*key)
Part of the
. Thread safety:
.This is the same as
, but key is specified as a constchar* UTF-8 encoded bytes string, rather than a
*.
intPyDict_GetItemRef(
*p,
*key,
**result)
Part of the
since version 3.13. Thread safety:
Safe for concurrent use on the same object
.Return a new
to the object from dictionary p which has a key key:
If the key is present, set *result to a new
to the value and return 1.
If the key is missing, set *result to NULL and return 0.
On error, raise an exception, set *result to NULL and return -1.
Added in version 3.13.
See also the
function.
*PyDict_GetItem(
*p,
*key)
Return value: Borrowed reference. Part of the
. Thread safety:
Safe to call from multiple threads with external synchronization only
.Return a
to the object from dictionary p which has a key key. Return NULL if the key key is missing without setting an exception.
Note
Exceptions that occur while this calls
and
methods are silently ignored. Prefer the
function instead.
Changed in version 3.10: Calling this API without an
had been allowed for historical reason. It is no longer allowed.
*PyDict_GetItemWithError(
*p,
*key)
Return value: Borrowed reference. Part of the
. Thread safety:
Safe to call from multiple threads with external synchronization only
.Variant of
that does not suppress exceptions. Return NULLwith an exception set if an exception occurred. Return NULLwithout an exception set if the key wasn’t present.
*PyDict_GetItemString(
*p, constchar*key)
Return value: Borrowed reference. Part of the
. Thread safety:
Safe to call from multiple threads with external synchronization only
.This is the same as
, but key is specified as a constchar* UTF-8 encoded bytes string, rather than a
*.
intPyDict_GetItemStringRef(
*p, constchar*key,
**result)
Part of the
since version 3.13. Thread safety:
.Similar to
, but key is specified as a constchar* UTF-8 encoded bytes string, rather than a
*.
Added in version 3.13.
*PyDict_SetDefault(
*p,
*key,
*defaultobj)
Return value: Borrowed reference. Thread safety:
Safe to call from multiple threads with external synchronization only
.This is the same as the Python-level
. If present, it returns the value corresponding to key from the dictionary p. If the key is not in the dict, it is inserted with value defaultobj and defaultobj is returned. This function evaluates the hash function of key only once, instead of evaluating it independently for the lookup and the insertion.
Added in version 3.4.
intPyDict_SetDefaultRef(
*p,
*key,
*default_value,
**result)
Thread safety:
Safe for concurrent use on the same object
.Inserts default_value into the dictionary p with a key of key if the key is not already present in the dictionary. If result is not NULL, then *result is set to a
to either default_value, if the key was not present, or the existing value, if key was already present in the dictionary. Returns 1 if the key was present and default_value was not inserted, or 0 if the key was not present and default_value was inserted. On failure, returns -1, sets an exception, and sets *result to NULL.
For clarity: if you have a strong reference to default_value before calling this function, then after it returns, you hold a strong reference to both default_value and *result (if it’s not NULL). These may refer to the same object: in that case you hold two separate references to it.
Added in version 3.13.
intPyDict_Pop(
*p,
*key,
**result)
Thread safety:
Safe for concurrent use on the same object
.Remove key from dictionary p and optionally return the removed value. Do not raise
if the key is missing.
If the key is present, set *result to a new reference to the removed value if result is not NULL, and return 1.
If the key is missing, set *result to NULL if result is not NULL, and return 0.
On error, raise an exception and return -1.
Similar to
, but without the default value and not raising
if the key is missing.
Added in version 3.13.
intPyDict_PopString(
*p, constchar*key,
**result)
Thread safety:
.Similar to
, but key is specified as a constchar* UTF-8 encoded bytes string, rather than a
*.
Added in version 3.13.
*PyDict_Items(
*p)
Return value: New reference. Part of the
. Thread safety:
.Return a
containing all the items from the dictionary.
*PyDict_Keys(
*p)
Return value: New reference. Part of the
. Thread safety:
.Return a
containing all the keys from the dictionary.
*PyDict_Values(
*p)
Return value: New reference. Part of the
. Thread safety:
.Return a
containing all the values from the dictionary p.
PyDict_Size(
*p)
Part of the
. Thread safety:
.Return the number of items in the dictionary. This is equivalent to len(p) on a dictionary.
PyDict_GET_SIZE(
*p)
Thread safety:
.Similar to
, but without error checking.
intPyDict_Next(
*p,
*ppos,
**pkey,
**pvalue)
Part of the
. Thread safety:
Safe to call from multiple threads with external synchronization only
.Iterate over all key-value pairs in the dictionary p. The
referred to by ppos must be initialized to 0 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 to
* 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_tpos=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 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_tpos=0;while(PyDict_Next(self->dict,&pos,&key,&value)){longi=PyLong_AsLong(value);if(i==-1&&PyErr_Occurred()){return-1;}PyObject*o=PyLong_FromLong(i+1);if(o==NULL)return-1;if(PyDict_SetItem(self->dict,key,o)<0){Py_DECREF(o);return-1;}Py_DECREF(o);}The function is not thread-safe in the
build without external synchronization. You can use
to lock the dictionary while iterating over it:
Py_BEGIN_CRITICAL_SECTION(self->dict);while(PyDict_Next(self->dict,&pos,&key,&value)){...}Py_END_CRITICAL_SECTION();Note
On the free-threaded build, this function can be used safely inside a critical section. However, the references returned for pkey and pvalue are
and are only valid while the critical section is held. If you need to use these objects outside the critical section or when the critical section can be suspended, create a
(for example, using
).
intPyDict_Merge(
*a,
*b, intoverride)
Part of the
. Thread safety:
Safe for concurrent use on the same object
.Iterate over mapping object b adding key-value pairs to dictionary a. b may be a dictionary, or any object supporting
and
. 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. Return 0 on success or -1 if an exception was raised.
Note
In the
, when b is a
(with the standard iterator), both a and b are locked for the duration of the operation. When b is a non-dict mapping, only a is locked; b may be concurrently modified by another thread.
intPyDict_Update(
*a,
*b)
Part of the
. Thread safety:
Safe for concurrent use on the same object
.This is the same as PyDict_Merge(a,b,1) in C, and is similar to a.update(b) in Python except that
doesn’t fall back to the iterating over a sequence of key value pairs if the second argument has no “keys” attribute. Return 0 on success or -1 if an exception was raised.
Note
In the
, when b is a
(with the standard iterator), both a and b are locked for the duration of the operation. When b is a non-dict mapping, only a is locked; b may be concurrently modified by another thread.
intPyDict_MergeFromSeq2(
*a,
*seq2, intoverride)
Part of the
. Thread safety:
Safe for concurrent use on the same object
.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):
defPyDict_MergeFromSeq2(a,seq2,override):forkey,valueinseq2:ifoverrideorkeynotina:a[key]=valueNote
In the
build, only a is locked. The iteration over seq2 is not synchronized; seq2 may be concurrently modified by another thread.
intPyDict_AddWatcher(
callback)
Thread safety:
Safe to call from multiple threads with external synchronization only
.Register callback as a dictionary watcher. Return a non-negative integer id which must be passed to future calls to
. In case of error (e.g. no more watcher IDs available), return -1 and set an exception.
Note
This function is not internally synchronized. In the
build, callers should ensure no concurrent calls to
or
are in progress.
Added in version 3.12.
intPyDict_ClearWatcher(intwatcher_id)
Thread safety:
Safe to call from multiple threads with external synchronization only
.Clear watcher identified by watcher_id previously returned from
. Return 0 on success, -1 on error (e.g. if the given watcher_id was never registered.)
Note
This function is not internally synchronized. In the
build, callers should ensure no concurrent calls to
or
are in progress.
Added in version 3.12.
intPyDict_Watch(intwatcher_id,
*dict)
Thread safety:
Safe to call without external synchronization on distinct objects
.Mark dictionary dict as watched. The callback granted watcher_id by
will be called when dict is modified or deallocated. Return 0 on success or -1 on error.
Added in version 3.12.
intPyDict_Unwatch(intwatcher_id,
*dict)
Thread safety:
Safe to call without external synchronization on distinct objects
.Mark dictionary dict as no longer watched. The callback granted watcher_id by
will no longer be called when dict is modified or deallocated. The dict must previously have been watched by this watcher. Return 0 on success or -1 on error.
Added in version 3.12.
typePyDict_WatchEvent
Enumeration of possible dictionary watcher events: PyDict_EVENT_ADDED, PyDict_EVENT_MODIFIED, PyDict_EVENT_DELETED, PyDict_EVENT_CLONED, PyDict_EVENT_CLEARED, or PyDict_EVENT_DEALLOCATED.
Added in version 3.12.
typedefint(*PyDict_WatchCallback)(
event,
*dict,
*key,
*new_value)
Type of a dict watcher callback function.
If event is PyDict_EVENT_CLEARED or PyDict_EVENT_DEALLOCATED, both key and new_value will be NULL. If event is PyDict_EVENT_ADDED or PyDict_EVENT_MODIFIED, new_value will be the new value for key. If event is PyDict_EVENT_DELETED, key is being deleted from the dictionary and new_value will be NULL.
PyDict_EVENT_CLONED occurs when dict was previously empty and another dict is merged into it. To maintain efficiency of this operation, per-key PyDict_EVENT_ADDED events are not issued in this case; instead a single PyDict_EVENT_CLONED is issued, and key will be the source dictionary.
The callback may inspect but must not modify dict; doing so could have unpredictable effects, including infinite recursion. Do not trigger Python code execution in the callback, as it could modify the dict as a side effect.
If event is PyDict_EVENT_DEALLOCATED, taking a new reference in the callback to the about-to-be-destroyed dictionary will resurrect it and prevent it from being freed at this time. When the resurrected object is destroyed later, any watcher callbacks active at that time will be called again.
Callbacks occur before the notified modification to dict takes place, so the prior state of dict can be inspected.
If the callback sets an exception, it must return -1; this exception will be printed as an unraisable exception using
. Otherwise it should return 0.
There may already be a pending exception set on entry to the callback. In this case, the callback should return 0 with the same exception still set. This means the callback may not call any other API that can set an exception unless it saves and clears the exception state first, and restores it before returning.
Added in version 3.12.
Dictionary View Objects
intPyDictViewSet_Check(
*op)
Return true if op is a view of a set inside a dictionary. This is currently equivalent to
(
)||
(op). This function always succeeds.
PyDictKeys_Type
Part of the
.Type object for a view of dictionary keys. In Python, this is the type of the object returned by
.
intPyDictKeys_Check(
*op)
Return true if op is an instance of a dictionary keys view. This function always succeeds.
PyDictValues_Type
Part of the
.Type object for a view of dictionary values. In Python, this is the type of the object returned by
.
intPyDictValues_Check(
*op)
Return true if op is an instance of a dictionary values view. This function always succeeds.
PyDictItems_Type
Part of the
.Type object for a view of dictionary items. In Python, this is the type of the object returned by
.
intPyDictItems_Check(
*op)
Return true if op is an instance of a dictionary items view. This function always succeeds.
Ordered Dictionaries
Python’s C API provides interface for
from C. Since Python 3.7, dictionaries are ordered by default, so there is usually little need for these functions; prefer PyDict* where possible.
PyODict_Type
Type object for ordered dictionaries. This is the same object as
in the Python layer.
intPyODict_Check(
*od)
Return true if od is an ordered dictionary object or an instance of a subtype of the
type. This function always succeeds.
intPyODict_CheckExact(
*od)
Return true if od is an ordered dictionary object, but not an instance of a subtype of the
type. This function always succeeds.
PyODictKeys_Type
Analogous to
for ordered dictionaries.
PyODictValues_Type
Analogous to
for ordered dictionaries.
PyODictItems_Type
Analogous to
for ordered dictionaries.
*PyODict_New(void)
Return a new empty ordered dictionary, or NULL on failure.
This is analogous to
.
intPyODict_SetItem(
*od,
*key,
*value)
Insert value into the ordered dictionary od with a key of key. Return 0 on success or -1 with an exception set on failure.
This is analogous to
.
intPyODict_DelItem(
*od,
*key)
Remove the entry in the ordered dictionary od with key key. Return 0 on success or -1 with an exception set on failure.
This is analogous to
.
These are
aliases to PyDict APIs:
PyODict
PyDict
PyODict_GetItem(od, key)
PyODict_GetItemWithError(od, key)
PyODict_GetItemString(od, key)
PyODict_Contains(od, key)
PyODict_Size(od)
PyODict_SIZE(od)