Sequence Protocol — Python 3.9.25 documentation

int PySequence_Check(

PyObject

*o)

Return 1 if the object provides the sequence protocol, and 0 otherwise. Note that it returns 1 for Python classes with a

__getitem__()

method, unless they are

dict

subclasses, since in general it is impossible to determine what type of keys the class supports. This function always succeeds.

Py_ssize_t

PySequence_Size(

PyObject

*o)

Py_ssize_t

PySequence_Length(

PyObject

*o)

Returns the number of objects in sequence o on success, and -1 on failure. This is equivalent to the Python expression len(o).

PyObject

* PySequence_Concat(

PyObject

*o1,

PyObject

*o2)

Return value: New reference.Return the concatenation of o1 and o2 on success, and NULL on failure. This is the equivalent of the Python expression o1+o2.

PyObject

* PySequence_Repeat(

PyObject

*o,

Py_ssize_t

count)

Return value: New reference.Return the result of repeating sequence object ocount times, or NULL on failure. This is the equivalent of the Python expression o*count.

PyObject

* PySequence_InPlaceConcat(

PyObject

*o1,

PyObject

*o2)

Return value: New reference.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.

PyObject

* PySequence_InPlaceRepeat(

PyObject

*o,

Py_ssize_t

count)

Return value: New reference.Return the result of repeating sequence object ocount 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.

PyObject

* PySequence_GetItem(

PyObject

*o,

Py_ssize_t

i)

Return value: New reference.Return the ith element of o, or NULL on failure. This is the equivalent of the Python expression o[i].

PyObject

* PySequence_GetSlice(

PyObject

*o,

Py_ssize_t

i1,

Py_ssize_t

i2)

Return value: New reference.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].

int PySequence_SetItem(

PyObject

*o,

Py_ssize_t

i,

PyObject

*v)

Assign object v to the ith element of o. Raise an exception and return -1 on failure; return 0 on success. This is the equivalent of the Python statement o[i]=v. This function does not steal a reference to v.

If v is NULL, the element is deleted, but this feature is deprecated in favour of using

PySequence_DelItem()

.

int PySequence_DelItem(

PyObject

*o,

Py_ssize_t

i)

Delete the ith element of object o. Returns -1 on failure. This is the equivalent of the Python statement delo[i].

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.

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 delo[i1:i2].

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).

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 valueino.

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).

PyObject

* PySequence_List(

PyObject

*o)

Return value: New reference.Return a list object with the same contents as the sequence or iterable o, or NULL on failure. The returned list is guaranteed to be new. This is equivalent to the Python expression list(o).

PyObject

* PySequence_Tuple(

PyObject

*o)

Return value: New reference.Return a tuple object with the same contents as the sequence or iterable 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).

PyObject

* PySequence_Fast(

PyObject

*o, const char *m)

Return value: New reference.Return the sequence or iterable o as an object usable by the other PySequence_Fast* family of functions. If the object is not a sequence or iterable, raises

TypeError

with m as the message text. Returns NULL on failure.

The PySequence_Fast* functions are thus named because they assume o is a

PyTupleObject

or a

PyListObject

and access the data fields of o directly.

As a CPython implementation detail, if o is already a sequence or list, it will be returned.

Py_ssize_t

PySequence_Fast_GET_SIZE(

PyObject

*o)

Returns the length of o, assuming that o was returned by

PySequence_Fast()

and that o is not NULL. The size can also be retrieved by calling

PySequence_Size()

on o, but

PySequence_Fast_GET_SIZE()

is faster because it can assume o is a list or tuple.

PyObject

* PySequence_Fast_GET_ITEM(

PyObject

*o,

Py_ssize_t

i)

Return value: Borrowed reference.Return the ith element of o, assuming that o was returned by

PySequence_Fast()

, o is not NULL, and that i is within bounds.

PyObject

** PySequence_Fast_ITEMS(

PyObject

*o)

Return the underlying array of PyObject pointers. Assumes that o was returned by

PySequence_Fast()

and o is not NULL.

Note, if a list gets resized, the reallocation may relocate the items array. So, only use the underlying array pointer in contexts where the sequence cannot change.

PyObject

* PySequence_ITEM(

PyObject

*o,

Py_ssize_t

i)

Return value: New reference.Return the ith element of o or NULL on failure. Faster form of

PySequence_GetItem()

but without checking that

PySequence_Check()

on o is true and without adjustment for negative indices.