ak.fill_none
------------

Defined in `awkward.operations.structure <https://github.com/scikit-hep/awkward-1.0/blob/80bbef0738a6b7928333d7c705ee1b359991de5b/src/awkward/operations/structure.py>`__ on `line 2791 <https://github.com/scikit-hep/awkward-1.0/blob/80bbef0738a6b7928333d7c705ee1b359991de5b/src/awkward/operations/structure.py#L2791>`__.

.. py:function:: ak.fill_none(array, value, axis=-1, highlevel=True, behavior=None)


    :param array: Data in which to replace None with a given value.
    :param value: Data with which to replace None.
    :param axis: If None, replace all None values in the array
             with the given value; if an int, The dimension at which this
             operation is applied. The outermost dimension is ``0``, followed
             by ``1``, etc., and negative values count backward from the
             innermost: ``-1`` is the innermost  dimension, ``-2`` is the next
             level up, etc.
    :type axis: None or int
    :param highlevel: If True, return an :py:obj:`ak.Array`; otherwise, return
                  a low-level :py:obj:`ak.layout.Content` subclass.
    :type highlevel: bool
    :param behavior: Custom :py:obj:`ak.behavior` for the output array, if
                 high-level.
    :type behavior: None or dict

Replaces missing values (None) with a given ``value``.

For example, in the following ``array``,

.. code-block:: python


    ak.Array([[1.1, None, 2.2], [], [None, 3.3, 4.4]])

The None values could be replaced with ``0`` by

.. code-block:: python


    >>> ak.fill_none(array, 0)
    <Array [[1.1, 0, 2.2], [], [0, 3.3, 4.4]] type='3 * var * float64'>

The replacement value doesn't strictly need the same type as the
surrounding data. For example, the None values could also be replaced
by a string.

.. code-block:: python


    >>> ak.fill_none(array, "hi")
    <Array [[1.1, 'hi', 2.2], ... ['hi', 3.3, 4.4]] type='3 * var * union[float64, s...'>

The list content now has a union type:

.. code-block:: python


    >>> ak.type(ak.fill_none(array, "hi"))
    3 * var * union[float64, string]

The values could be floating-point numbers or strings.

