mirror of https://github.com/python/cpython
1026 lines
37 KiB
ReStructuredText
1026 lines
37 KiB
ReStructuredText
.. highlightlang:: c
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.. _abstract:
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**********************
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Abstract Objects Layer
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**********************
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The functions in this chapter interact with Python objects regardless of their
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type, or with wide classes of object types (e.g. all numerical types, or all
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sequence types). When used on object types for which they do not apply, they
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will raise a Python exception.
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It is not possible to use these functions on objects that are not properly
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initialized, such as a list object that has been created by :cfunc:`PyList_New`,
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but whose items have not been set to some non-\ ``NULL`` value yet.
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.. _object:
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Object Protocol
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===============
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.. cfunction:: int PyObject_Print(PyObject *o, FILE *fp, int flags)
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Print an object *o*, on file *fp*. Returns ``-1`` on error. The flags argument
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is used to enable certain printing options. The only option currently supported
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is :const:`Py_PRINT_RAW`; if given, the :func:`str` of the object is written
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instead of the :func:`repr`.
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.. cfunction:: int PyObject_HasAttr(PyObject *o, PyObject *attr_name)
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Returns ``1`` if *o* has the attribute *attr_name*, and ``0`` otherwise. This
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is equivalent to the Python expression ``hasattr(o, attr_name)``. This function
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always succeeds.
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.. cfunction:: int PyObject_HasAttrString(PyObject *o, const char *attr_name)
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Returns ``1`` if *o* has the attribute *attr_name*, and ``0`` otherwise. This
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is equivalent to the Python expression ``hasattr(o, attr_name)``. This function
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always succeeds.
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.. cfunction:: PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name)
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Retrieve an attribute named *attr_name* from object *o*. Returns the attribute
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value on success, or *NULL* on failure. This is the equivalent of the Python
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expression ``o.attr_name``.
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.. cfunction:: PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name)
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Retrieve an attribute named *attr_name* from object *o*. Returns the attribute
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value on success, or *NULL* on failure. This is the equivalent of the Python
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expression ``o.attr_name``.
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.. cfunction:: int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v)
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Set the value of the attribute named *attr_name*, for object *o*, to the value
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*v*. Returns ``-1`` on failure. This is the equivalent of the Python statement
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``o.attr_name = v``.
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.. cfunction:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
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Set the value of the attribute named *attr_name*, for object *o*, to the value
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*v*. Returns ``-1`` on failure. This is the equivalent of the Python statement
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``o.attr_name = v``.
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.. cfunction:: int PyObject_DelAttr(PyObject *o, PyObject *attr_name)
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Delete attribute named *attr_name*, for object *o*. Returns ``-1`` on failure.
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This is the equivalent of the Python statement ``del o.attr_name``.
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.. cfunction:: int PyObject_DelAttrString(PyObject *o, const char *attr_name)
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Delete attribute named *attr_name*, for object *o*. Returns ``-1`` on failure.
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This is the equivalent of the Python statement ``del o.attr_name``.
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.. cfunction:: PyObject* PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)
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Compare the values of *o1* and *o2* using the operation specified by *opid*,
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which must be one of :const:`Py_LT`, :const:`Py_LE`, :const:`Py_EQ`,
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:const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``,
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``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. This is the equivalent of
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the Python expression ``o1 op o2``, where ``op`` is the operator corresponding
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to *opid*. Returns the value of the comparison on success, or *NULL* on failure.
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.. cfunction:: int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid)
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Compare the values of *o1* and *o2* using the operation specified by *opid*,
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which must be one of :const:`Py_LT`, :const:`Py_LE`, :const:`Py_EQ`,
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:const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``,
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``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. Returns ``-1`` on error,
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``0`` if the result is false, ``1`` otherwise. This is the equivalent of the
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Python expression ``o1 op o2``, where ``op`` is the operator corresponding to
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*opid*.
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.. cfunction:: int PyObject_Cmp(PyObject *o1, PyObject *o2, int *result)
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.. index:: builtin: cmp
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Compare the values of *o1* and *o2* using a routine provided by *o1*, if one
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exists, otherwise with a routine provided by *o2*. The result of the comparison
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is returned in *result*. Returns ``-1`` on failure. This is the equivalent of
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the Python statement ``result = cmp(o1, o2)``.
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.. cfunction:: int PyObject_Compare(PyObject *o1, PyObject *o2)
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.. index:: builtin: cmp
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Compare the values of *o1* and *o2* using a routine provided by *o1*, if one
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exists, otherwise with a routine provided by *o2*. Returns the result of the
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comparison on success. On error, the value returned is undefined; use
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:cfunc:`PyErr_Occurred` to detect an error. This is equivalent to the Python
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expression ``cmp(o1, o2)``.
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.. cfunction:: PyObject* PyObject_Repr(PyObject *o)
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.. index:: builtin: repr
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Compute a string representation of object *o*. Returns the string
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representation on success, *NULL* on failure. This is the equivalent of the
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Python expression ``repr(o)``. Called by the :func:`repr` built-in function and
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by reverse quotes.
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.. cfunction:: PyObject* PyObject_Str(PyObject *o)
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.. index:: builtin: str
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Compute a string representation of object *o*. Returns the string
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representation on success, *NULL* on failure. This is the equivalent of the
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Python expression ``str(o)``. Called by the :func:`str` built-in function and
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by the :keyword:`print` statement.
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.. cfunction:: PyObject* PyObject_Unicode(PyObject *o)
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.. index:: builtin: unicode
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Compute a Unicode string representation of object *o*. Returns the Unicode
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string representation on success, *NULL* on failure. This is the equivalent of
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the Python expression ``unicode(o)``. Called by the :func:`unicode` built-in
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function.
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.. cfunction:: int PyObject_IsInstance(PyObject *inst, PyObject *cls)
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Returns ``1`` if *inst* is an instance of the class *cls* or a subclass of
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*cls*, or ``0`` if not. On error, returns ``-1`` and sets an exception. If
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*cls* is a type object rather than a class object, :cfunc:`PyObject_IsInstance`
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returns ``1`` if *inst* is of type *cls*. If *cls* is a tuple, the check will
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be done against every entry in *cls*. The result will be ``1`` when at least one
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of the checks returns ``1``, otherwise it will be ``0``. If *inst* is not a
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class instance and *cls* is neither a type object, nor a class object, nor a
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tuple, *inst* must have a :attr:`__class__` attribute --- the class relationship
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of the value of that attribute with *cls* will be used to determine the result
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of this function.
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.. versionadded:: 2.1
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.. versionchanged:: 2.2
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Support for a tuple as the second argument added.
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Subclass determination is done in a fairly straightforward way, but includes a
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wrinkle that implementors of extensions to the class system may want to be aware
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of. If :class:`A` and :class:`B` are class objects, :class:`B` is a subclass of
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:class:`A` if it inherits from :class:`A` either directly or indirectly. If
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either is not a class object, a more general mechanism is used to determine the
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class relationship of the two objects. When testing if *B* is a subclass of
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*A*, if *A* is *B*, :cfunc:`PyObject_IsSubclass` returns true. If *A* and *B*
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are different objects, *B*'s :attr:`__bases__` attribute is searched in a
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depth-first fashion for *A* --- the presence of the :attr:`__bases__` attribute
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is considered sufficient for this determination.
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.. cfunction:: int PyObject_IsSubclass(PyObject *derived, PyObject *cls)
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Returns ``1`` if the class *derived* is identical to or derived from the class
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*cls*, otherwise returns ``0``. In case of an error, returns ``-1``. If *cls*
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is a tuple, the check will be done against every entry in *cls*. The result will
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be ``1`` when at least one of the checks returns ``1``, otherwise it will be
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``0``. If either *derived* or *cls* is not an actual class object (or tuple),
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this function uses the generic algorithm described above.
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.. versionadded:: 2.1
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.. versionchanged:: 2.3
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Older versions of Python did not support a tuple as the second argument.
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.. cfunction:: int PyCallable_Check(PyObject *o)
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Determine if the object *o* is callable. Return ``1`` if the object is callable
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and ``0`` otherwise. This function always succeeds.
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.. cfunction:: PyObject* PyObject_Call(PyObject *callable_object, PyObject *args, PyObject *kw)
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.. index:: builtin: apply
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Call a callable Python object *callable_object*, with arguments given by the
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tuple *args*, and named arguments given by the dictionary *kw*. If no named
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arguments are needed, *kw* may be *NULL*. *args* must not be *NULL*, use an
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empty tuple if no arguments are needed. Returns the result of the call on
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success, or *NULL* on failure. This is the equivalent of the Python expression
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``apply(callable_object, args, kw)`` or ``callable_object(*args, **kw)``.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyObject_CallObject(PyObject *callable_object, PyObject *args)
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.. index:: builtin: apply
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Call a callable Python object *callable_object*, with arguments given by the
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tuple *args*. If no arguments are needed, then *args* may be *NULL*. Returns
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the result of the call on success, or *NULL* on failure. This is the equivalent
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of the Python expression ``apply(callable_object, args)`` or
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``callable_object(*args)``.
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.. cfunction:: PyObject* PyObject_CallFunction(PyObject *callable, char *format, ...)
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.. index:: builtin: apply
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Call a callable Python object *callable*, with a variable number of C arguments.
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The C arguments are described using a :cfunc:`Py_BuildValue` style format
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string. The format may be *NULL*, indicating that no arguments are provided.
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Returns the result of the call on success, or *NULL* on failure. This is the
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equivalent of the Python expression ``apply(callable, args)`` or
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``callable(*args)``. Note that if you only pass :ctype:`PyObject \*` args,
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:cfunc:`PyObject_CallFunctionObjArgs` is a faster alternative.
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.. cfunction:: PyObject* PyObject_CallMethod(PyObject *o, char *method, char *format, ...)
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Call the method named *method* of object *o* with a variable number of C
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arguments. The C arguments are described by a :cfunc:`Py_BuildValue` format
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string that should produce a tuple. The format may be *NULL*, indicating that
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no arguments are provided. Returns the result of the call on success, or *NULL*
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on failure. This is the equivalent of the Python expression ``o.method(args)``.
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Note that if you only pass :ctype:`PyObject \*` args,
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:cfunc:`PyObject_CallMethodObjArgs` is a faster alternative.
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.. cfunction:: PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL)
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Call a callable Python object *callable*, with a variable number of
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:ctype:`PyObject\*` arguments. The arguments are provided as a variable number
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of parameters followed by *NULL*. Returns the result of the call on success, or
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*NULL* on failure.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyObject_CallMethodObjArgs(PyObject *o, PyObject *name, ..., NULL)
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Calls a method of the object *o*, where the name of the method is given as a
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Python string object in *name*. It is called with a variable number of
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:ctype:`PyObject\*` arguments. The arguments are provided as a variable number
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of parameters followed by *NULL*. Returns the result of the call on success, or
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*NULL* on failure.
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.. versionadded:: 2.2
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.. cfunction:: long PyObject_Hash(PyObject *o)
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.. index:: builtin: hash
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Compute and return the hash value of an object *o*. On failure, return ``-1``.
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This is the equivalent of the Python expression ``hash(o)``.
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.. cfunction:: int PyObject_IsTrue(PyObject *o)
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Returns ``1`` if the object *o* is considered to be true, and ``0`` otherwise.
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This is equivalent to the Python expression ``not not o``. On failure, return
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``-1``.
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.. cfunction:: int PyObject_Not(PyObject *o)
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Returns ``0`` if the object *o* is considered to be true, and ``1`` otherwise.
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This is equivalent to the Python expression ``not o``. On failure, return
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``-1``.
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.. cfunction:: PyObject* PyObject_Type(PyObject *o)
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.. index:: builtin: type
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When *o* is non-*NULL*, returns a type object corresponding to the object type
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of object *o*. On failure, raises :exc:`SystemError` and returns *NULL*. This
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is equivalent to the Python expression ``type(o)``. This function increments the
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reference count of the return value. There's really no reason to use this
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function instead of the common expression ``o->ob_type``, which returns a
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pointer of type :ctype:`PyTypeObject\*`, except when the incremented reference
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count is needed.
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.. cfunction:: int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)
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Return true if the object *o* is of type *type* or a subtype of *type*. Both
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parameters must be non-*NULL*.
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.. versionadded:: 2.2
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.. cfunction:: Py_ssize_t PyObject_Length(PyObject *o)
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Py_ssize_t PyObject_Size(PyObject *o)
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.. index:: builtin: len
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Return the length of object *o*. If the object *o* provides either the sequence
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and mapping protocols, the sequence length is returned. On error, ``-1`` is
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returned. This is the equivalent to the Python expression ``len(o)``.
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.. cfunction:: PyObject* PyObject_GetItem(PyObject *o, PyObject *key)
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Return element of *o* corresponding to the object *key* or *NULL* on failure.
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This is the equivalent of the Python expression ``o[key]``.
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.. cfunction:: int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)
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Map the object *key* to the value *v*. Returns ``-1`` on failure. This is the
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equivalent of the Python statement ``o[key] = v``.
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.. cfunction:: int PyObject_DelItem(PyObject *o, PyObject *key)
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Delete the mapping for *key* from *o*. Returns ``-1`` on failure. This is the
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equivalent of the Python statement ``del o[key]``.
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.. cfunction:: int PyObject_AsFileDescriptor(PyObject *o)
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Derives a file descriptor from a Python object. If the object is an integer or
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long integer, its value is returned. If not, the object's :meth:`fileno` method
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is called if it exists; the method must return an integer or long integer, which
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is returned as the file descriptor value. Returns ``-1`` on failure.
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.. cfunction:: PyObject* PyObject_Dir(PyObject *o)
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This is equivalent to the Python expression ``dir(o)``, returning a (possibly
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empty) list of strings appropriate for the object argument, or *NULL* if there
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was an error. If the argument is *NULL*, this is like the Python ``dir()``,
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returning the names of the current locals; in this case, if no execution frame
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is active then *NULL* is returned but :cfunc:`PyErr_Occurred` will return false.
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.. cfunction:: PyObject* PyObject_GetIter(PyObject *o)
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This is equivalent to the Python expression ``iter(o)``. It returns a new
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iterator for the object argument, or the object itself if the object is already
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an iterator. Raises :exc:`TypeError` and returns *NULL* if the object cannot be
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iterated.
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.. _number:
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Number Protocol
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===============
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.. cfunction:: int PyNumber_Check(PyObject *o)
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Returns ``1`` if the object *o* provides numeric protocols, and false otherwise.
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This function always succeeds.
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.. cfunction:: PyObject* PyNumber_Add(PyObject *o1, PyObject *o2)
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Returns the result of adding *o1* and *o2*, or *NULL* on failure. This is the
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equivalent of the Python expression ``o1 + o2``.
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.. cfunction:: PyObject* PyNumber_Subtract(PyObject *o1, PyObject *o2)
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Returns the result of subtracting *o2* from *o1*, or *NULL* on failure. This is
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the equivalent of the Python expression ``o1 - o2``.
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.. cfunction:: PyObject* PyNumber_Multiply(PyObject *o1, PyObject *o2)
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Returns the result of multiplying *o1* and *o2*, or *NULL* on failure. This is
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the equivalent of the Python expression ``o1 * o2``.
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.. cfunction:: PyObject* PyNumber_Divide(PyObject *o1, PyObject *o2)
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Returns the result of dividing *o1* by *o2*, or *NULL* on failure. This is the
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equivalent of the Python expression ``o1 / o2``.
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.. cfunction:: PyObject* PyNumber_FloorDivide(PyObject *o1, PyObject *o2)
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Return the floor of *o1* divided by *o2*, or *NULL* on failure. This is
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equivalent to the "classic" division of integers.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyNumber_TrueDivide(PyObject *o1, PyObject *o2)
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Return a reasonable approximation for the mathematical value of *o1* divided by
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*o2*, or *NULL* on failure. The return value is "approximate" because binary
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floating point numbers are approximate; it is not possible to represent all real
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numbers in base two. This function can return a floating point value when
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passed two integers.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyNumber_Remainder(PyObject *o1, PyObject *o2)
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Returns the remainder of dividing *o1* by *o2*, or *NULL* on failure. This is
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the equivalent of the Python expression ``o1 % o2``.
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.. cfunction:: PyObject* PyNumber_Divmod(PyObject *o1, PyObject *o2)
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.. index:: builtin: divmod
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See the built-in function :func:`divmod`. Returns *NULL* on failure. This is
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the equivalent of the Python expression ``divmod(o1, o2)``.
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.. cfunction:: PyObject* PyNumber_Power(PyObject *o1, PyObject *o2, PyObject *o3)
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.. index:: builtin: pow
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See the built-in function :func:`pow`. Returns *NULL* on failure. This is the
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equivalent of the Python expression ``pow(o1, o2, o3)``, where *o3* is optional.
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If *o3* is to be ignored, pass :cdata:`Py_None` in its place (passing *NULL* for
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*o3* would cause an illegal memory access).
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.. cfunction:: PyObject* PyNumber_Negative(PyObject *o)
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Returns the negation of *o* on success, or *NULL* on failure. This is the
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equivalent of the Python expression ``-o``.
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.. cfunction:: PyObject* PyNumber_Positive(PyObject *o)
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Returns *o* on success, or *NULL* on failure. This is the equivalent of the
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Python expression ``+o``.
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.. cfunction:: PyObject* PyNumber_Absolute(PyObject *o)
|
|
|
|
.. index:: builtin: abs
|
|
|
|
Returns the absolute value of *o*, or *NULL* on failure. This is the equivalent
|
|
of the Python expression ``abs(o)``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Invert(PyObject *o)
|
|
|
|
Returns the bitwise negation of *o* on success, or *NULL* on failure. This is
|
|
the equivalent of the Python expression ``~o``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Lshift(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of left shifting *o1* by *o2* on success, or *NULL* on
|
|
failure. This is the equivalent of the Python expression ``o1 << o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Rshift(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of right shifting *o1* by *o2* on success, or *NULL* on
|
|
failure. This is the equivalent of the Python expression ``o1 >> o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_And(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the "bitwise and" of *o1* and *o2* on success and *NULL* on failure.
|
|
This is the equivalent of the Python expression ``o1 & o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Xor(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the "bitwise exclusive or" of *o1* by *o2* on success, or *NULL* on
|
|
failure. This is the equivalent of the Python expression ``o1 ^ o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Or(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the "bitwise or" of *o1* and *o2* on success, or *NULL* on failure.
|
|
This is the equivalent of the Python expression ``o1 | o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceAdd(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of adding *o1* and *o2*, or *NULL* on failure. The operation
|
|
is done *in-place* when *o1* supports it. This is the equivalent of the Python
|
|
statement ``o1 += o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceSubtract(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of subtracting *o2* from *o1*, or *NULL* on failure. The
|
|
operation is done *in-place* when *o1* supports it. This is the equivalent of
|
|
the Python statement ``o1 -= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceMultiply(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of multiplying *o1* and *o2*, or *NULL* on failure. The
|
|
operation is done *in-place* when *o1* supports it. This is the equivalent of
|
|
the Python statement ``o1 *= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceDivide(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of dividing *o1* by *o2*, or *NULL* on failure. The
|
|
operation is done *in-place* when *o1* supports it. This is the equivalent of
|
|
the Python statement ``o1 /= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceFloorDivide(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the mathematical floor of dividing *o1* by *o2*, or *NULL* on failure.
|
|
The operation is done *in-place* when *o1* supports it. This is the equivalent
|
|
of the Python statement ``o1 //= o2``.
|
|
|
|
.. versionadded:: 2.2
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceTrueDivide(PyObject *o1, PyObject *o2)
|
|
|
|
Return a reasonable approximation for the mathematical value of *o1* divided by
|
|
*o2*, or *NULL* on failure. The return value is "approximate" because binary
|
|
floating point numbers are approximate; it is not possible to represent all real
|
|
numbers in base two. This function can return a floating point value when
|
|
passed two integers. The operation is done *in-place* when *o1* supports it.
|
|
|
|
.. versionadded:: 2.2
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceRemainder(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the remainder of dividing *o1* by *o2*, or *NULL* on failure. The
|
|
operation is done *in-place* when *o1* supports it. This is the equivalent of
|
|
the Python statement ``o1 %= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlacePower(PyObject *o1, PyObject *o2, PyObject *o3)
|
|
|
|
.. index:: builtin: pow
|
|
|
|
See the built-in function :func:`pow`. Returns *NULL* on failure. The operation
|
|
is done *in-place* when *o1* supports it. This is the equivalent of the Python
|
|
statement ``o1 **= o2`` when o3 is :cdata:`Py_None`, or an in-place variant of
|
|
``pow(o1, o2, o3)`` otherwise. If *o3* is to be ignored, pass :cdata:`Py_None`
|
|
in its place (passing *NULL* for *o3* would cause an illegal memory access).
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceLshift(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of left shifting *o1* by *o2* on success, or *NULL* on
|
|
failure. The operation is done *in-place* when *o1* supports it. This is the
|
|
equivalent of the Python statement ``o1 <<= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceRshift(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the result of right shifting *o1* by *o2* on success, or *NULL* on
|
|
failure. The operation is done *in-place* when *o1* supports it. This is the
|
|
equivalent of the Python statement ``o1 >>= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceAnd(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the "bitwise and" of *o1* and *o2* on success and *NULL* on failure. The
|
|
operation is done *in-place* when *o1* supports it. This is the equivalent of
|
|
the Python statement ``o1 &= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceXor(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the "bitwise exclusive or" of *o1* by *o2* on success, or *NULL* on
|
|
failure. The operation is done *in-place* when *o1* supports it. This is the
|
|
equivalent of the Python statement ``o1 ^= o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_InPlaceOr(PyObject *o1, PyObject *o2)
|
|
|
|
Returns the "bitwise or" of *o1* and *o2* on success, or *NULL* on failure. The
|
|
operation is done *in-place* when *o1* supports it. This is the equivalent of
|
|
the Python statement ``o1 |= o2``.
|
|
|
|
|
|
.. cfunction:: int PyNumber_Coerce(PyObject **p1, PyObject **p2)
|
|
|
|
.. index:: builtin: coerce
|
|
|
|
This function takes the addresses of two variables of type :ctype:`PyObject\*`.
|
|
If the objects pointed to by ``*p1`` and ``*p2`` have the same type, increment
|
|
their reference count and return ``0`` (success). If the objects can be
|
|
converted to a common numeric type, replace ``*p1`` and ``*p2`` by their
|
|
converted value (with 'new' reference counts), and return ``0``. If no
|
|
conversion is possible, or if some other error occurs, return ``-1`` (failure)
|
|
and don't increment the reference counts. The call ``PyNumber_Coerce(&o1,
|
|
&o2)`` is equivalent to the Python statement ``o1, o2 = coerce(o1, o2)``.
|
|
|
|
|
|
.. cfunction:: int PyNumber_CoerceEx(PyObject **p1, PyObject **p2)
|
|
|
|
This function is similar to :cfunc:`PyNumber_Coerce`, except that it returns
|
|
``1`` when the conversion is not possible and when no error is raised.
|
|
Reference counts are still not increased in this case.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Int(PyObject *o)
|
|
|
|
.. index:: builtin: int
|
|
|
|
Returns the *o* converted to an integer object on success, or *NULL* on failure.
|
|
If the argument is outside the integer range a long object will be returned
|
|
instead. This is the equivalent of the Python expression ``int(o)``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Long(PyObject *o)
|
|
|
|
.. index:: builtin: long
|
|
|
|
Returns the *o* converted to a long integer object on success, or *NULL* on
|
|
failure. This is the equivalent of the Python expression ``long(o)``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Float(PyObject *o)
|
|
|
|
.. index:: builtin: float
|
|
|
|
Returns the *o* converted to a float object on success, or *NULL* on failure.
|
|
This is the equivalent of the Python expression ``float(o)``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyNumber_Index(PyObject *o)
|
|
|
|
Returns the *o* converted to a Python int or long on success or *NULL* with a
|
|
TypeError exception raised on failure.
|
|
|
|
.. versionadded:: 2.5
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PyNumber_AsSsize_t(PyObject *o, PyObject *exc)
|
|
|
|
Returns *o* converted to a Py_ssize_t value if *o* can be interpreted as an
|
|
integer. If *o* can be converted to a Python int or long but the attempt to
|
|
convert to a Py_ssize_t value would raise an :exc:`OverflowError`, then the
|
|
*exc* argument is the type of exception that will be raised (usually
|
|
:exc:`IndexError` or :exc:`OverflowError`). If *exc* is *NULL*, then the
|
|
exception is cleared and the value is clipped to *PY_SSIZE_T_MIN* for a negative
|
|
integer or *PY_SSIZE_T_MAX* for a positive integer.
|
|
|
|
.. versionadded:: 2.5
|
|
|
|
|
|
.. cfunction:: int PyIndex_Check(PyObject *o)
|
|
|
|
Returns True if *o* is an index integer (has the nb_index slot of the
|
|
tp_as_number structure filled in).
|
|
|
|
.. versionadded:: 2.5
|
|
|
|
|
|
.. _sequence:
|
|
|
|
Sequence Protocol
|
|
=================
|
|
|
|
|
|
.. cfunction:: int PySequence_Check(PyObject *o)
|
|
|
|
Return ``1`` if the object provides sequence protocol, and ``0`` otherwise.
|
|
This function always succeeds.
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PySequence_Size(PyObject *o)
|
|
|
|
.. index:: builtin: len
|
|
|
|
Returns the number of objects in sequence *o* on success, and ``-1`` on failure.
|
|
For objects that do not provide sequence protocol, this is equivalent to the
|
|
Python expression ``len(o)``.
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PySequence_Length(PyObject *o)
|
|
|
|
Alternate name for :cfunc:`PySequence_Size`.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_Concat(PyObject *o1, PyObject *o2)
|
|
|
|
Return the concatenation of *o1* and *o2* on success, and *NULL* on failure.
|
|
This is the equivalent of the Python expression ``o1 + o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count)
|
|
|
|
Return the result of repeating sequence object *o* *count* times, or *NULL* on
|
|
failure. This is the equivalent of the Python expression ``o * count``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2)
|
|
|
|
Return the concatenation of *o1* and *o2* on success, and *NULL* on failure.
|
|
The operation is done *in-place* when *o1* supports it. This is the equivalent
|
|
of the Python expression ``o1 += o2``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count)
|
|
|
|
Return the result of repeating sequence object *o* *count* times, or *NULL* on
|
|
failure. The operation is done *in-place* when *o* supports it. This is the
|
|
equivalent of the Python expression ``o *= count``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i)
|
|
|
|
Return the *i*th element of *o*, or *NULL* on failure. This is the equivalent of
|
|
the Python expression ``o[i]``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)
|
|
|
|
Return the slice of sequence object *o* between *i1* and *i2*, or *NULL* on
|
|
failure. This is the equivalent of the Python expression ``o[i1:i2]``.
|
|
|
|
|
|
.. cfunction:: int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v)
|
|
|
|
Assign object *v* to the *i*th element of *o*. Returns ``-1`` on failure. This
|
|
is the equivalent of the Python statement ``o[i] = v``. This function *does
|
|
not* steal a reference to *v*.
|
|
|
|
|
|
.. cfunction:: int PySequence_DelItem(PyObject *o, Py_ssize_t i)
|
|
|
|
Delete the *i*th element of object *o*. Returns ``-1`` on failure. This is the
|
|
equivalent of the Python statement ``del o[i]``.
|
|
|
|
|
|
.. cfunction:: int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v)
|
|
|
|
Assign the sequence object *v* to the slice in sequence object *o* from *i1* to
|
|
*i2*. This is the equivalent of the Python statement ``o[i1:i2] = v``.
|
|
|
|
|
|
.. cfunction:: int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)
|
|
|
|
Delete the slice in sequence object *o* from *i1* to *i2*. Returns ``-1`` on
|
|
failure. This is the equivalent of the Python statement ``del o[i1:i2]``.
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PySequence_Count(PyObject *o, PyObject *value)
|
|
|
|
Return the number of occurrences of *value* in *o*, that is, return the number
|
|
of keys for which ``o[key] == value``. On failure, return ``-1``. This is
|
|
equivalent to the Python expression ``o.count(value)``.
|
|
|
|
|
|
.. cfunction:: int PySequence_Contains(PyObject *o, PyObject *value)
|
|
|
|
Determine if *o* contains *value*. If an item in *o* is equal to *value*,
|
|
return ``1``, otherwise return ``0``. On error, return ``-1``. This is
|
|
equivalent to the Python expression ``value in o``.
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PySequence_Index(PyObject *o, PyObject *value)
|
|
|
|
Return the first index *i* for which ``o[i] == value``. On error, return
|
|
``-1``. This is equivalent to the Python expression ``o.index(value)``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_List(PyObject *o)
|
|
|
|
Return a list object with the same contents as the arbitrary sequence *o*. The
|
|
returned list is guaranteed to be new.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_Tuple(PyObject *o)
|
|
|
|
.. index:: builtin: tuple
|
|
|
|
Return a tuple object with the same contents as the arbitrary sequence *o* or
|
|
*NULL* on failure. If *o* is a tuple, a new reference will be returned,
|
|
otherwise a tuple will be constructed with the appropriate contents. This is
|
|
equivalent to the Python expression ``tuple(o)``.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_Fast(PyObject *o, const char *m)
|
|
|
|
Returns the sequence *o* as a tuple, unless it is already a tuple or list, in
|
|
which case *o* is returned. Use :cfunc:`PySequence_Fast_GET_ITEM` to access the
|
|
members of the result. Returns *NULL* on failure. If the object is not a
|
|
sequence, raises :exc:`TypeError` with *m* as the message text.
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i)
|
|
|
|
Return the *i*th element of *o*, assuming that *o* was returned by
|
|
:cfunc:`PySequence_Fast`, *o* is not *NULL*, and that *i* is within bounds.
|
|
|
|
|
|
.. cfunction:: PyObject** PySequence_Fast_ITEMS(PyObject *o)
|
|
|
|
Return the underlying array of PyObject pointers. Assumes that *o* was returned
|
|
by :cfunc:`PySequence_Fast` and *o* is not *NULL*.
|
|
|
|
.. versionadded:: 2.4
|
|
|
|
|
|
.. cfunction:: PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i)
|
|
|
|
Return the *i*th element of *o* or *NULL* on failure. Macro form of
|
|
:cfunc:`PySequence_GetItem` but without checking that
|
|
:cfunc:`PySequence_Check(o)` is true and without adjustment for negative
|
|
indices.
|
|
|
|
.. versionadded:: 2.3
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)
|
|
|
|
Returns the length of *o*, assuming that *o* was returned by
|
|
:cfunc:`PySequence_Fast` and that *o* is not *NULL*. The size can also be
|
|
gotten by calling :cfunc:`PySequence_Size` on *o*, but
|
|
:cfunc:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list
|
|
or tuple.
|
|
|
|
|
|
.. _mapping:
|
|
|
|
Mapping Protocol
|
|
================
|
|
|
|
|
|
.. cfunction:: int PyMapping_Check(PyObject *o)
|
|
|
|
Return ``1`` if the object provides mapping protocol, and ``0`` otherwise. This
|
|
function always succeeds.
|
|
|
|
|
|
.. cfunction:: Py_ssize_t PyMapping_Length(PyObject *o)
|
|
|
|
.. index:: builtin: len
|
|
|
|
Returns the number of keys in object *o* on success, and ``-1`` on failure. For
|
|
objects that do not provide mapping protocol, this is equivalent to the Python
|
|
expression ``len(o)``.
|
|
|
|
|
|
.. cfunction:: int PyMapping_DelItemString(PyObject *o, char *key)
|
|
|
|
Remove the mapping for object *key* from the object *o*. Return ``-1`` on
|
|
failure. This is equivalent to the Python statement ``del o[key]``.
|
|
|
|
|
|
.. cfunction:: int PyMapping_DelItem(PyObject *o, PyObject *key)
|
|
|
|
Remove the mapping for object *key* from the object *o*. Return ``-1`` on
|
|
failure. This is equivalent to the Python statement ``del o[key]``.
|
|
|
|
|
|
.. cfunction:: int PyMapping_HasKeyString(PyObject *o, char *key)
|
|
|
|
On success, return ``1`` if the mapping object has the key *key* and ``0``
|
|
otherwise. This is equivalent to the Python expression ``o.has_key(key)``.
|
|
This function always succeeds.
|
|
|
|
|
|
.. cfunction:: int PyMapping_HasKey(PyObject *o, PyObject *key)
|
|
|
|
Return ``1`` if the mapping object has the key *key* and ``0`` otherwise. This
|
|
is equivalent to the Python expression ``o.has_key(key)``. This function always
|
|
succeeds.
|
|
|
|
|
|
.. cfunction:: PyObject* PyMapping_Keys(PyObject *o)
|
|
|
|
On success, return a list of the keys in object *o*. On failure, return *NULL*.
|
|
This is equivalent to the Python expression ``o.keys()``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyMapping_Values(PyObject *o)
|
|
|
|
On success, return a list of the values in object *o*. On failure, return
|
|
*NULL*. This is equivalent to the Python expression ``o.values()``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyMapping_Items(PyObject *o)
|
|
|
|
On success, return a list of the items in object *o*, where each item is a tuple
|
|
containing a key-value pair. On failure, return *NULL*. This is equivalent to
|
|
the Python expression ``o.items()``.
|
|
|
|
|
|
.. cfunction:: PyObject* PyMapping_GetItemString(PyObject *o, char *key)
|
|
|
|
Return element of *o* corresponding to the object *key* or *NULL* on failure.
|
|
This is the equivalent of the Python expression ``o[key]``.
|
|
|
|
|
|
.. cfunction:: int PyMapping_SetItemString(PyObject *o, char *key, PyObject *v)
|
|
|
|
Map the object *key* to the value *v* in object *o*. Returns ``-1`` on failure.
|
|
This is the equivalent of the Python statement ``o[key] = v``.
|
|
|
|
|
|
.. _iterator:
|
|
|
|
Iterator Protocol
|
|
=================
|
|
|
|
.. versionadded:: 2.2
|
|
|
|
There are only a couple of functions specifically for working with iterators.
|
|
|
|
|
|
.. cfunction:: int PyIter_Check(PyObject *o)
|
|
|
|
Return true if the object *o* supports the iterator protocol.
|
|
|
|
|
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.. cfunction:: PyObject* PyIter_Next(PyObject *o)
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Return the next value from the iteration *o*. If the object is an iterator,
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this retrieves the next value from the iteration, and returns *NULL* with no
|
|
exception set if there are no remaining items. If the object is not an
|
|
iterator, :exc:`TypeError` is raised, or if there is an error in retrieving the
|
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item, returns *NULL* and passes along the exception.
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|
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To write a loop which iterates over an iterator, the C code should look
|
|
something like this::
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|
PyObject *iterator = PyObject_GetIter(obj);
|
|
PyObject *item;
|
|
|
|
if (iterator == NULL) {
|
|
/* propagate error */
|
|
}
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|
|
|
while (item = PyIter_Next(iterator)) {
|
|
/* do something with item */
|
|
...
|
|
/* release reference when done */
|
|
Py_DECREF(item);
|
|
}
|
|
|
|
Py_DECREF(iterator);
|
|
|
|
if (PyErr_Occurred()) {
|
|
/* propagate error */
|
|
}
|
|
else {
|
|
/* continue doing useful work */
|
|
}
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|
.. _abstract-buffer:
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|
|
|
Buffer Protocol
|
|
===============
|
|
|
|
|
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.. cfunction:: int PyObject_AsCharBuffer(PyObject *obj, const char **buffer, Py_ssize_t *buffer_len)
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|
Returns a pointer to a read-only memory location useable as character- based
|
|
input. The *obj* argument must support the single-segment character buffer
|
|
interface. On success, returns ``0``, sets *buffer* to the memory location and
|
|
*buffer_len* to the buffer length. Returns ``-1`` and sets a :exc:`TypeError`
|
|
on error.
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|
|
|
.. versionadded:: 1.6
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|
|
|
|
.. cfunction:: int PyObject_AsReadBuffer(PyObject *obj, const void **buffer, Py_ssize_t *buffer_len)
|
|
|
|
Returns a pointer to a read-only memory location containing arbitrary data. The
|
|
*obj* argument must support the single-segment readable buffer interface. On
|
|
success, returns ``0``, sets *buffer* to the memory location and *buffer_len* to
|
|
the buffer length. Returns ``-1`` and sets a :exc:`TypeError` on error.
|
|
|
|
.. versionadded:: 1.6
|
|
|
|
|
|
.. cfunction:: int PyObject_CheckReadBuffer(PyObject *o)
|
|
|
|
Returns ``1`` if *o* supports the single-segment readable buffer interface.
|
|
Otherwise returns ``0``.
|
|
|
|
.. versionadded:: 2.2
|
|
|
|
|
|
.. cfunction:: int PyObject_AsWriteBuffer(PyObject *obj, void **buffer, Py_ssize_t *buffer_len)
|
|
|
|
Returns a pointer to a writeable memory location. The *obj* argument must
|
|
support the single-segment, character buffer interface. On success, returns
|
|
``0``, sets *buffer* to the memory location and *buffer_len* to the buffer
|
|
length. Returns ``-1`` and sets a :exc:`TypeError` on error.
|
|
|
|
.. versionadded:: 1.6
|
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|