Are numeric types objects?
>>> isinstance[1, object]
True
Apparently they are. :-].
Note that you might need to adjust your mental model of an object a little. It seems to me that you're thinking of object as something that is "mutable" -- that isn't the case. In reality, we need to think of python names as a reference to an object. That object may hold references to other objects.
name = something
Here, the right hand side is evaluated -- All the names are resolved into objects and the result of the expression [an object] is referenced by "name".
Ok, now lets consider what happens when you pass something to a function.
def foo[x]:
x = 2
z = 3
foo[z]
print[z]
What do we expect to happen here? Well, first we create the function foo. Next, we create the object 3 and reference it by the name z. After that, we look up the value that z references and pass that value to foo. Upon entering foo, that value gets referenced by the [local] name x. We
then create the object 2 and reference it by the local name x. Note, x has nothing to do with the global z -- They're independent references. Just because they were referencing the same object when you enter the function doesn't mean that they have to reference the function for all time. We can change what a name references at any point by using an assignment statement.
Note, your example with += may seem to complicate things, but you can think of a += 10 as
a = a + 10 if it helps in this context. For more information on += check out: When is "i += x" different from "i = i + x" in Python?
All integers are implemented as “long” integer objects of arbitrary size.
On error, most PyLong_As* APIs return [return type]-1 which cannot be distinguished from a number. Use PyErr_Occurred[] to disambiguate.
PyLongObject¶Part of the Limited API [as an opaque struct].
This subtype of PyObject represents a Python integer object.
PyLong_Type¶Part of the Stable ABI.
This instance of
PyTypeObject represents the Python integer type. This is the same object as int in the Python layer.
PyLong_Check[PyObject
*p]¶Return true if its argument is a PyLongObject or a subtype of PyLongObject. This function always succeeds.
PyLong_CheckExact[PyObject *p]¶Return true if its argument is a PyLongObject, but not
a subtype of PyLongObject. This function always succeeds.
PyLong_FromLong[long
v]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject object from v, or NULL on
failure.
The current implementation keeps an array of integer objects for all integers between -5 and 256. When you create an int in that range you actually just get back a reference to the existing object.
PyLong_FromUnsignedLong[unsigned long
v]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject object from a C unsigned
long, or NULL on failure.
PyLong_FromSsize_t[Py_ssize_t v]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject object from a C Py_ssize_t, or NULL on failure.
PyLong_FromSize_t[size_t v]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject object from a C size_t, or NULL on failure.
PyLong_FromLongLong[long long
v]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject object from a C long
long, or NULL on failure.
PyLong_FromUnsignedLongLong[unsigned long long v]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject object from a C unsigned long long, or NULL on failure.
PyLong_FromDouble[double v]¶Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject object from the integer part of v, or NULL on failure.
PyLong_FromString[const char *str, char **pend, int
base]¶Return value: New reference. Part of the Stable ABI.
Return a new PyLongObject based on the string value in
str, which is interpreted according to the radix in base. If pend is non-NULL, *pend will point to the first character in str which follows the representation of the number. If base is 0, str is interpreted using the Integer literals definition; in this case, leading zeros in a non-zero decimal number raises a ValueError. If base is not 0, it must be between 2 and 36, inclusive. Leading spaces and single underscores after a base specifier and between digits are ignored. If there are no digits, ValueError will be raised.
PyLong_FromUnicodeObject[PyObject *u, int base]¶Return value: New reference.
Convert a sequence of Unicode digits in the string u to a Python integer value.
New in version 3.3.
PyObject *PyLong_FromVoidPtr[void
*p]¶Return value: New reference. Part of the Stable ABI.
Create a Python integer from the pointer p. The pointer value can be retrieved from the resulting value using
PyLong_AsVoidPtr[].
PyLong_AsLong[PyObject *obj]¶Part of the Stable ABI.
Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __index__[] method [if present] to convert it to a
PyLongObject.
Raise OverflowError if the value of obj is out of range for a long.
Returns -1 on error. Use PyErr_Occurred[] to
disambiguate.
Changed in version 3.8: Use __index__[] if available.
Changed in version 3.10: This function will no longer use __int__[].
PyLong_AsLongAndOverflow[PyObject *obj, int
*overflow]¶Part of the Stable ABI.
Return a C long representation of obj. If obj is not an instance of
PyLongObject, first call its __index__[] method [if present] to convert it to a PyLongObject.
If the value of obj is greater than LONG_MAX or less than LONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow
to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.
Returns -1 on error. Use PyErr_Occurred[] to disambiguate.
Changed in version 3.8: Use __index__[] if available.
Changed in version 3.10: This function will no longer use __int__[].
PyLong_AsLongLong[PyObject *obj]¶Part of the Stable ABI.
Return a C long long
representation of obj. If obj is not an instance of PyLongObject, first call its __index__[] method [if present] to convert it to a PyLongObject.
Raise
OverflowError if the value of obj is out of range for a long long.
Returns -1 on error. Use PyErr_Occurred[] to disambiguate.
Changed in version 3.8: Use __index__[] if available.
Changed
in version 3.10: This function will no longer use __int__[].
PyLong_AsLongLongAndOverflow[PyObject *obj, int *overflow]¶Part of the Stable ABI.
Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__[] method [if present] to convert it to a
PyLongObject.
If the value of obj is greater than LLONG_MAX or less than LLONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.
Returns -1 on error. Use
PyErr_Occurred[] to disambiguate.
New in version 3.2.
Changed in version 3.8: Use __index__[] if available.
Changed in version 3.10: This function will no longer use __int__[].
PyLong_AsSsize_t[PyObject *pylong]¶Part of the Stable ABI.
Return a C Py_ssize_t representation of pylong. pylong must be an instance of PyLongObject.
Raise
OverflowError if the value of pylong is out of range for a Py_ssize_t.
Returns -1 on error. Use PyErr_Occurred[] to disambiguate.
PyLong_AsUnsignedLong[PyObject *pylong]¶Part of the Stable ABI.
Return a C unsigned long representation of pylong. pylong must be an instance of PyLongObject.
Raise OverflowError if the value of pylong is out of range for a unsigned long.
Returns [unsigned long]-1 on error. Use
PyErr_Occurred[] to disambiguate.
PyLong_AsSize_t[PyObject *pylong]¶Part of the Stable ABI.
Return a C size_t representation of pylong. pylong must be an instance of PyLongObject.
Raise OverflowError if
the value of pylong is out of range for a size_t.
Returns [size_t]-1 on error. Use PyErr_Occurred[] to disambiguate.
PyLong_AsUnsignedLongLong[PyObject
*pylong]¶Part of the Stable ABI.
Return a C unsigned long long representation of pylong. pylong must be an instance of
PyLongObject.
Raise OverflowError if the value of pylong is out of range for an unsigned long long.
Returns [unsigned long long]-1 on error. Use
PyErr_Occurred[] to disambiguate.
PyLong_AsUnsignedLongMask[PyObject
*obj]¶Part of the Stable ABI.
Return a C unsigned long representation of obj. If obj is not an instance of PyLongObject, first call its __index__[] method [if present] to convert it to a PyLongObject.
If the value of obj is out of range for an unsigned long, return the reduction of that value modulo ULONG_MAX + 1.
Returns [unsigned long]-1 on error. Use
PyErr_Occurred[] to disambiguate.
Changed in version 3.8: Use __index__[] if available.
Changed in version 3.10: This function will no longer use __int__[].
PyLong_AsUnsignedLongLongMask[PyObject *obj]¶Part of the Stable ABI.
Return a C
unsigned long long representation of obj. If obj is not an instance of PyLongObject, first call its __index__[] method [if present] to convert it to a PyLongObject.
If the value of obj is out of range for an unsigned long long, return
the reduction of that value modulo ULLONG_MAX + 1.
Returns [unsigned long long]-1 on error. Use PyErr_Occurred[] to disambiguate.
Changed in version 3.8: Use __index__[] if available.
Changed in version 3.10: This function will no longer use __int__[].
PyLong_AsDouble[PyObject *pylong]¶Part of the Stable ABI.
Return a C double
representation of pylong. pylong must be an instance of PyLongObject.
Raise OverflowError if the value of pylong is out of range for a double.
Returns -1.0 on error. Use
PyErr_Occurred[] to disambiguate.
PyLong_AsVoidPtr[PyObject *pylong]¶Part of the Stable ABI.
Convert a Python integer pylong to a C void pointer. If pylong cannot be converted, an OverflowError will be raised. This is only assured to produce a usable void pointer for values created with
PyLong_FromVoidPtr[].
Returns NULL on error. Use PyErr_Occurred[] to disambiguate.