# 字典物件

type PyDictObject

  `PyObject` 子型態代表一個 Python 字典物件。

PyTypeObject PyDict_Type
  為 穩定 ABI 的一部分.

  `PyTypeObject` 實例代表一個 Python 字典型態。此與 Python 層中的 `dict` 為同一個物件。

int PyDict_Check(PyObject *p)

  若 p 是一個字典物件或字典的子型態實例則會回傳 true。此函式每次都會執行成功。

int PyDict_CheckExact(PyObject *p)

  若 p 是一個字典物件但並不是一個字典子型態的實例，則回傳 true。此函式每次都會執行成功。

PyObject *PyDict_New()
  回傳值：新的參照。 為 穩定 ABI 的一部分.

  回傳一個新的空字典，或在失敗時回傳 `NULL`。

PyObject *PyDictProxy_New(PyObject *mapping)
  回傳值：新的參照。 為 穩定 ABI 的一部分.

  Return a `types.MappingProxyType` 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.

void PyDict_Clear(PyObject *p)
  為 穩定 ABI 的一部分.

  Empty an existing dictionary of all key-value pairs.

int PyDict_Contains(PyObject *p, PyObject *key)
  為 穩定 ABI 的一部分.

  Determine if dictionary p contains key. If an item in p is matches key, return `1`, otherwise return `0`. On error, return `-1`. This is equivalent to the Python expression `key in p`.

PyObject *PyDict_Copy(PyObject *p)
  回傳值：新的參照。 為 穩定 ABI 的一部分.

  Return a new dictionary that contains the same key-value pairs as p.

int PyDict_SetItem(PyObject *p, PyObject *key, PyObject *val)
  為 穩定 ABI 的一部分.

  Insert val into the dictionary p with a key of key. key must be hashable; if it isn't, `TypeError` will be raised. Return `0` on success or `-1` on failure. This function does not steal a reference to val.

int PyDict_SetItemString(PyObject *p, const char *key, PyObject *val)
  為 穩定 ABI 的一部分.

  This is the same as `PyDict_SetItem()`, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

int PyDict_DelItem(PyObject *p, PyObject *key)
  為 穩定 ABI 的一部分.

  Remove the entry in dictionary p with key key. key must be hashable; if it isn't, `TypeError` is raised. If key is not in the dictionary, `KeyError` is raised. Return `0` on success or `-1` on failure.

int PyDict_DelItemString(PyObject *p, const char *key)
  為 穩定 ABI 的一部分.

  This is the same as `PyDict_DelItem()`, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

PyObject *PyDict_GetItem(PyObject *p, PyObject *key)
  回傳值：借用參照。 為 穩定 ABI 的一部分.

  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.

  備註

  Exceptions that occur while this calls `__hash__()` and `__eq__()` methods are silently ignored. Prefer the `PyDict_GetItemWithError()` function instead.

  在 3.10 版的變更: Calling this API without GIL held had been allowed for historical reason. It is no longer allowed.

PyObject *PyDict_GetItemWithError(PyObject *p, PyObject *key)
  回傳值：借用參照。 為 穩定 ABI 的一部分.

  Variant of `PyDict_GetItem()` that does not suppress exceptions. Return `NULL` with an exception set if an exception occurred. Return `NULL` without an exception set if the key wasn't present.

PyObject *PyDict_GetItemString(PyObject *p, const char *key)
  回傳值：借用參照。 為 穩定 ABI 的一部分.

  This is the same as `PyDict_GetItem()`, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

  備註

  Exceptions that occur while this calls `__hash__()` and `__eq__()` methods or while creating the temporary `str` object are silently ignored. Prefer using the `PyDict_GetItemWithError()` function with your own `PyUnicode_FromString()` key instead.

PyObject *PyDict_SetDefault(PyObject *p, PyObject *key, PyObject *defaultobj)
  回傳值：借用參照。

  This is the same as the Python-level `dict.setdefault()`. 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.

  在 3.4 版被加入.

PyObject *PyDict_Items(PyObject *p)
  回傳值：新的參照。 為 穩定 ABI 的一部分.

  Return a `PyListObject` containing all the items from the dictionary.

PyObject *PyDict_Keys(PyObject *p)
  回傳值：新的參照。 為 穩定 ABI 的一部分.

  Return a `PyListObject` containing all the keys from the dictionary.

PyObject *PyDict_Values(PyObject *p)
  回傳值：新的參照。 為 穩定 ABI 的一部分.

  Return a `PyListObject` containing all the values from the dictionary p.

Py_ssize_t PyDict_Size(PyObject *p)
  為 穩定 ABI 的一部分.

  Return the number of items in the dictionary. This is equivalent to `len(p)` on a dictionary.

int PyDict_Next(PyObject *p, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue)
  為 穩定 ABI 的一部分.

  Iterate over all key-value pairs in the dictionary p. The `Py_ssize_t` 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 PyObject* 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.

  舉例來說：

      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 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)) {
          long i = 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);
      }

int PyDict_Merge(PyObject *a, PyObject *b, int override)
  為 穩定 ABI 的一部分.

  Iterate over mapping object b adding key-value pairs to dictionary a. b may be a dictionary, or any object supporting `PyMapping_Keys()` and `PyObject_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. Return `0` on success or `-1` if an exception was raised.

int PyDict_Update(PyObject *a, PyObject *b)
  為 穩定 ABI 的一部分.

  This is the same as `PyDict_Merge(a, b, 1)` in C, and is similar to `a.update(b)` in Python except that `PyDict_Update()` 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.

int PyDict_MergeFromSeq2(PyObject *a, PyObject *seq2, int override)
  為 穩定 ABI 的一部分.

  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

int PyDict_AddWatcher(PyDict_WatchCallback callback)

  Register callback as a dictionary watcher. Return a non-negative integer id which must be passed to future calls to `PyDict_Watch()`. In case of error (e.g. no more watcher IDs available), return `-1` and set an exception.

  在 3.12 版被加入.

int PyDict_ClearWatcher(int watcher_id)

  Clear watcher identified by watcher_id previously returned from `PyDict_AddWatcher()`. Return `0` on success, `-1` on error (e.g. if the given watcher_id was never registered.)

  在 3.12 版被加入.

int PyDict_Watch(int watcher_id, PyObject *dict)

  Mark dictionary dict as watched. The callback granted watcher_id by `PyDict_AddWatcher()` will be called when dict is modified or deallocated. Return `0` on success or `-1` on error.

  在 3.12 版被加入.

int PyDict_Unwatch(int watcher_id, PyObject *dict)

  Mark dictionary dict as no longer watched. The callback granted watcher_id by `PyDict_AddWatcher()` 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.

  在 3.12 版被加入.

type PyDict_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`.

  在 3.12 版被加入.

typedef int (*PyDict_WatchCallback)(PyDict_WatchEvent event, PyObject *dict, PyObject *key, PyObject *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 `PyErr_WriteUnraisable()`. 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.

  在 3.12 版被加入.