# 字典物件

type PyDictObject

  `PyObject` 子型別代表一個 Python 字典物件。

PyTypeObject PyDict_Type
  為 穩定 ABI 的一部分.

  `PyTypeObject` 實例代表一個 Python 字典型別。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別實例則會回傳 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別的實例，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.

PyTypeObject PyDictProxy_Type
  為 穩定 ABI 的一部分.

  The type object for mapping proxy objects created by `PyDictProxy_New()` and for the read-only `__dict__` attribute of many built-in types. A `PyDictProxy_Type` 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 `types.MappingProxyType` in Python.

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

  清空現有字典中的所有鍵值對。

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 matches key, return `1`, otherwise return `0`. On error, return `-1`. This is equivalent to the Python expression `key in p`.

int PyDict_ContainsString(PyObject *p, const char *key)

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

  在 3.13 版被加入.

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

  回傳一個新的字典，包含與 p 相同的鍵值對。

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*.

int PyDict_GetItemRef(PyObject *p, PyObject *key, PyObject **result)
  為 穩定 ABI 的一部分 自 3.13 版本開始.

  Return a new strong reference to the object from dictionary p which has a key key:

  - If the key is present, set *result to a new strong reference to the value and return `1`.

  - 如果鍵不存在，將 *result 設為 `NULL` 並回傳 `0`。

  - 錯誤發生時，引發一個例外並回傳 `-1`。

  在 3.13 版被加入.

  另見 `PyObject_GetItem()` 函式。

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

  Return a borrowed reference to the object from dictionary p which has a key key. Return `NULL` if the key key is missing 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 an attached thread state 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.

int PyDict_GetItemStringRef(PyObject *p, const char *key, PyObject **result)
  為 穩定 ABI 的一部分 自 3.13 版本開始.

  Similar to `PyDict_GetItemRef()`, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

  在 3.13 版被加入.

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.

int PyDict_SetDefaultRef(PyObject *p, PyObject *key, PyObject *default_value, PyObject **result)
  為 穩定 ABI 的一部分 自 3.15 版本開始.

  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 strong reference 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.

  在 3.13 版被加入.

int PyDict_Pop(PyObject *p, PyObject *key, PyObject **result)

  Remove key from dictionary p and optionally return the removed value. Do not raise `KeyError` 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`.

  - 錯誤發生時，引發一個例外並回傳 `-1`。

  Similar to `dict.pop()`, but without the default value and not raising `KeyError` if the key is missing.

  在 3.13 版被加入.

int PyDict_PopString(PyObject *p, const char *key, PyObject **result)

  Similar to `PyDict_Pop()`, but key is specified as a const char* UTF-8 encoded bytes string, rather than a PyObject*.

  在 3.13 版被加入.

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

  回傳一個包含字典中所有項目的 `PyListObject`。

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

  回傳一個包含字典中所有鍵的 `PyListObject`。

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

  回傳一個包含字典 p 中所有值的 `PyListObject`。

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

  回傳字典中項目的數量。此與於字典呼叫 `len(p)` 等效。

Py_ssize_t PyDict_GET_SIZE(PyObject *p)

  和 `PyDict_Size()` 類似，但沒有錯誤檢查。

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)) {
          /* 用值做一些有趣的事情... */
          ...
      }

  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);
      }

  The function is not thread-safe in the free-threaded build without external synchronization. You can use `Py_BEGIN_CRITICAL_SECTION` 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();

  備註

  On the free-threaded build, this function can be used safely inside a critical section. However, the references returned for pkey and pvalue are borrowed 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 strong reference (for example, using `Py_NewRef()`).

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.

## 字典視圖物件

int PyDictViewSet_Check(PyObject *op)

  若 op 是一個字典中集合的視圖則會回傳 true。這目前等同於 PyDictKeys_Check(op) || PyDictItems_Check(op)。此函式每次都會執行成功。

PyTypeObject PyDictKeys_Type
  為 穩定 ABI 的一部分.

  Type object for a view of dictionary keys. In Python, this is the type of the object returned by `dict.keys()`.

int PyDictKeys_Check(PyObject *op)

  若 op 是一個字典鍵視圖的實例則會回傳 true。此函式每次都會執行成功。

PyTypeObject PyDictValues_Type
  為 穩定 ABI 的一部分.

  Type object for a view of dictionary values. In Python, this is the type of the object returned by `dict.values()`.

int PyDictValues_Check(PyObject *op)

  若 op 是一個字典值視圖的實例則會回傳 true。此函式每次都會執行成功。

PyTypeObject PyDictItems_Type
  為 穩定 ABI 的一部分.

  Type object for a view of dictionary items. In Python, this is the type of the object returned by `dict.items()`.

int PyDictItems_Check(PyObject *op)

  若 op 是一個字典項目視圖的實例則會回傳 true。此函式每次都會執行成功。

## 有序字典

Python's C API provides interface for `collections.OrderedDict` from C. Since Python 3.7, dictionaries are ordered by default, so there is usually little need for these functions; prefer `PyDict*` where possible.

PyTypeObject PyODict_Type

  有序字典的型別物件。此與 Python 層中的 `collections.OrderedDict` 為同一個物件。

int PyODict_Check(PyObject *od)

  若 od 是一個有序字典物件或 `OrderedDict` 的子型別實例則會回傳 true。此函式每次都會執行成功。

int PyODict_CheckExact(PyObject *od)

  若 od 是一個有序字典物件但並不是一個 `OrderedDict` 子型別的實例，則回傳 true。此函式每次都會執行成功。

PyTypeObject PyODictKeys_Type

  Analogous to `PyDictKeys_Type` for ordered dictionaries.

PyTypeObject PyODictValues_Type

  Analogous to `PyDictValues_Type` for ordered dictionaries.

PyTypeObject PyODictItems_Type

  Analogous to `PyDictItems_Type` for ordered dictionaries.

PyObject *PyODict_New(void)

  回傳一個新的空有序字典，或在失敗時回傳 `NULL`。

  這和 `PyDict_New()` 類似。

int PyODict_SetItem(PyObject *od, PyObject *key, PyObject *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.

  這和 `PyDict_SetItem()` 類似。

int PyODict_DelItem(PyObject *od, PyObject *key)

  Remove the entry in the ordered dictionary od with key key. Return `0` on success or `-1` with an exception set on failure.

  這和 `PyDict_DelItem()` 類似。

These are soft deprecated aliases to `PyDict` APIs:

`PyODict` | `PyDict`
--- | ---
PyODict_GetItem(od, key) | `PyDict_GetItem()`
PyODict_GetItemWithError(od, key) | `PyDict_GetItemWithError()`
PyODict_GetItemString(od, key) | `PyDict_GetItemString()`
PyODict_Contains(od, key) | `PyDict_Contains()`
PyODict_Size(od) | `PyDict_Size()`
PyODict_SIZE(od) | `PyDict_GET_SIZE()`