Cell Objects — Python 3.13.3 documentation
Description: “Cell” objects are used to implement variables referenced by multiple scopes. For each such variable, a cell object is created to store the value; the local variables of each stack frame that refer...

# Cell Objects

“Cell” objects are used to implement variables referenced by multiple scopes. For each such variable, a cell object is created to store the value; the local variables of each stack frame that references the value contains a reference to the cells from outer scopes which also use that variable. When the value is accessed, the value contained in the cell is used instead of the cell object itself. This de-referencing of the cell object requires support from the generated byte-code; these are not automatically de-referenced when accessed. Cell objects are not likely to be useful elsewhere.

type PyCellObject

  The C structure used for cell objects.

PyTypeObject PyCell_Type

  The type object corresponding to cell objects.

int PyCell_Check(PyObject *ob)

  Return true if ob is a cell object; ob must not be `NULL`. This function always succeeds.

PyObject *PyCell_New(PyObject *ob)
  Return value: New reference.

  Create and return a new cell object containing the value ob. The parameter may be `NULL`.

PyObject *PyCell_Get(PyObject *cell)
  Return value: New reference.

  Return the contents of the cell cell, which can be `NULL`. If cell is not a cell object, returns `NULL` with an exception set.

PyObject *PyCell_GET(PyObject *cell)
  Return value: Borrowed reference.

  Return the contents of the cell cell, but without checking that cell is non-`NULL` and a cell object.

int PyCell_Set(PyObject *cell, PyObject *value)

  Set the contents of the cell object cell to value. This releases the reference to any current content of the cell. value may be `NULL`. cell must be non-`NULL`.

  On success, return `0`. If cell is not a cell object, set an exception and return `-1`.

void PyCell_SET(PyObject *cell, PyObject *value)

  Sets the value of the cell object cell to value. No reference counts are adjusted, and no checks are made for safety; cell must be non-`NULL` and must be a cell object.