Iterator Objects — Python 3.14.3 documentation
Description: Python provides two general-purpose iterator objects. The first, a sequence iterator, works with an arbitrary sequence supporting the__getitem__() method. The second works with a callable object an...

# Iterator Objects

Python provides two general-purpose iterator objects. The first, a sequence iterator, works with an arbitrary sequence supporting the `__getitem__()` method. The second works with a callable object and a sentinel value, calling the callable for each item in the sequence, and ending the iteration when the sentinel value is returned.

PyTypeObject PySeqIter_Type
  Part of the Stable ABI.

  Type object for iterator objects returned by `PySeqIter_New()` and the one-argument form of the `iter()` built-in function for built-in sequence types.

int PySeqIter_Check(PyObject *op)

  Return true if the type of op is `PySeqIter_Type`. This function always succeeds.

PyObject *PySeqIter_New(PyObject *seq)
  Return value: New reference. Part of the Stable ABI.

  Return an iterator that works with a general sequence object, seq. The iteration ends when the sequence raises `IndexError` for the subscripting operation.

PyTypeObject PyCallIter_Type
  Part of the Stable ABI.

  Type object for iterator objects returned by `PyCallIter_New()` and the two-argument form of the `iter()` built-in function.

int PyCallIter_Check(PyObject *op)

  Return true if the type of op is `PyCallIter_Type`. This function always succeeds.

PyObject *PyCallIter_New(PyObject *callable, PyObject *sentinel)
  Return value: New reference. Part of the Stable ABI.

  Return a new iterator. The first parameter, callable, can be any Python callable object that can be called with no parameters; each call to it should return the next item in the iteration. When callable returns a value equal to sentinel, the iteration will be terminated.

## Range Objects

PyTypeObject PyRange_Type
  Part of the Stable ABI.

  The type object for `range` objects.

int PyRange_Check(PyObject *o)

  Return true if the object o is an instance of a `range` object. This function always succeeds.

## Builtin Iterator Types

These are built-in iteration types that are included in Python’s C API, but provide no additional functions. They are here for completeness.

C type | Python type
--- | ---
PyTypeObject PyEnum_Type Part of the Stable ABI. | `enumerate`
PyTypeObject PyFilter_Type Part of the Stable ABI. | `filter`
PyTypeObject PyMap_Type Part of the Stable ABI. | `map`
PyTypeObject PyReversed_Type Part of the Stable ABI. | `reversed`
PyTypeObject PyZip_Type Part of the Stable ABI. | `zip`

## Other Iterator Objects

PyTypeObject PyByteArrayIter_Type
  Part of the Stable ABI.

PyTypeObject PyBytesIter_Type
  Part of the Stable ABI.

PyTypeObject PyListIter_Type
  Part of the Stable ABI.

PyTypeObject PyListRevIter_Type
  Part of the Stable ABI.

PyTypeObject PySetIter_Type
  Part of the Stable ABI.

PyTypeObject PyTupleIter_Type
  Part of the Stable ABI.

PyTypeObject PyRangeIter_Type
  Part of the Stable ABI.

PyTypeObject PyLongRangeIter_Type
  Part of the Stable ABI.

PyTypeObject PyDictIterKey_Type
  Part of the Stable ABI.

PyTypeObject PyDictRevIterKey_Type
  Part of the Stable ABI since version 3.8.

PyTypeObject PyDictIterValue_Type
  Part of the Stable ABI.

PyTypeObject PyDictRevIterValue_Type
  Part of the Stable ABI since version 3.8.

PyTypeObject PyDictIterItem_Type
  Part of the Stable ABI.

PyTypeObject PyDictRevIterItem_Type
  Part of the Stable ABI since version 3.8.

PyTypeObject PyODictIter_Type

  Type objects for iterators of various built-in objects.

  Do not create instances of these directly; prefer calling `PyObject_GetIter()` instead.

  Note that there is no guarantee that a given built-in type uses a given iterator type. For example, iterating over `range` will use one of two iterator types depending on the size of the range. Other types may start using a similar scheme in the future, without warning.