Set Objects¶
This section details the public API for set and frozenset
objects. Any functionality not listed below is best accessed using either
the abstract object protocol (including PyObject_CallMethod(),
PyObject_RichCompareBool(), PyObject_Hash(),
PyObject_Repr(), PyObject_IsTrue(), PyObject_Print(), and
PyObject_GetIter()) or the abstract number protocol (including
PyNumber_And(), PyNumber_Subtract(), PyNumber_Or(),
PyNumber_Xor(), PyNumber_InPlaceAnd(),
PyNumber_InPlaceSubtract(), PyNumber_InPlaceOr(), and
PyNumber_InPlaceXor()).
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PySetObject¶ This subtype of
PyObjectis used to hold the internal data for bothsetandfrozensetobjects. It is like aPyDictObjectin that it is a fixed size for small sets (much like tuple storage) and will point to a separate, variable sized block of memory for medium and large sized sets (much like list storage). None of the fields of this structure should be considered public and all are subject to change. All access should be done through the documented API rather than by manipulating the values in the structure.
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PyTypeObject
PySet_Type¶ This is an instance of
PyTypeObjectrepresenting the Pythonsettype.
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PyTypeObject
PyFrozenSet_Type¶ This is an instance of
PyTypeObjectrepresenting the Pythonfrozensettype.
The following type check macros work on pointers to any Python object. Likewise, the constructor functions work with any iterable Python object.
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int
PySet_Check(PyObject *p)¶ Return true if p is a
setobject or an instance of a subtype. This function always succeeds.
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int
PyFrozenSet_Check(PyObject *p)¶ Return true if p is a
frozensetobject or an instance of a subtype. This function always succeeds.
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int
PyAnySet_Check(PyObject *p)¶ Return true if p is a
setobject, afrozensetobject, or an instance of a subtype. This function always succeeds.
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int
PyAnySet_CheckExact(PyObject *p)¶ Return true if p is a
setobject or afrozensetobject but not an instance of a subtype. This function always succeeds.
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int
PyFrozenSet_CheckExact(PyObject *p)¶ Return true if p is a
frozensetobject but not an instance of a subtype. This function always succeeds.
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PyObject*
PySet_New(PyObject *iterable)¶ - Return value: New reference.
Return a new
setcontaining objects returned by the iterable. The iterable may beNULLto create a new empty set. Return the new set on success orNULLon failure. RaiseTypeErrorif iterable is not actually iterable. The constructor is also useful for copying a set (c=set(s)).
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PyObject*
PyFrozenSet_New(PyObject *iterable)¶ - Return value: New reference.
Return a new
frozensetcontaining objects returned by the iterable. The iterable may beNULLto create a new empty frozenset. Return the new set on success orNULLon failure. RaiseTypeErrorif iterable is not actually iterable.
The following functions and macros are available for instances of set
or frozenset or instances of their subtypes.
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Py_ssize_t
PySet_Size(PyObject *anyset)¶ Return the length of a
setorfrozensetobject. Equivalent tolen(anyset). Raises aPyExc_SystemErrorif anyset is not aset,frozenset, or an instance of a subtype.
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Py_ssize_t
PySet_GET_SIZE(PyObject *anyset)¶ Macro form of
PySet_Size()without error checking.
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int
PySet_Contains(PyObject *anyset, PyObject *key)¶ Return
1if found,0if not found, and-1if an error is encountered. Unlike the Python__contains__()method, this function does not automatically convert unhashable sets into temporary frozensets. Raise aTypeErrorif the key is unhashable. RaisePyExc_SystemErrorif anyset is not aset,frozenset, or an instance of a subtype.
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int
PySet_Add(PyObject *set, PyObject *key)¶ Add key to a
setinstance. Also works withfrozensetinstances (likePyTuple_SetItem()it can be used to fill in the values of brand new frozensets before they are exposed to other code). Return0on success or-1on failure. Raise aTypeErrorif the key is unhashable. Raise aMemoryErrorif there is no room to grow. Raise aSystemErrorif set is not an instance ofsetor its subtype.
The following functions are available for instances of set or its
subtypes but not for instances of frozenset or its subtypes.
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int
PySet_Discard(PyObject *set, PyObject *key)¶ Return
1if found and removed,0if not found (no action taken), and-1if an error is encountered. Does not raiseKeyErrorfor missing keys. Raise aTypeErrorif the key is unhashable. Unlike the Pythondiscard()method, this function does not automatically convert unhashable sets into temporary frozensets. RaisePyExc_SystemErrorif set is not an instance ofsetor its subtype.