ak.singletons
-------------

Defined in `awkward.operations.structure <https://github.com/scikit-hep/awkward-1.0/blob/80bbef0738a6b7928333d7c705ee1b359991de5b/src/awkward/operations/structure.py>`__ on `line 2969 <https://github.com/scikit-hep/awkward-1.0/blob/80bbef0738a6b7928333d7c705ee1b359991de5b/src/awkward/operations/structure.py#L2969>`__.

.. py:function:: ak.singletons(array, highlevel=True, behavior=None)


    :param array: Data to wrap in lists of length 1 if present and length 0
              if missing (None).
    :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

Returns a singleton list (length 1) wrapping each non-missing value and
an empty list (length 0) in place of each missing value.

For example,

.. code-block:: python


    >>> array = ak.Array([1.1, 2.2, None, 3.3, None, None, 4.4, 5.5])
    >>> print(ak.singletons(array))
    [[1.1], [2.2], [], [3.3], [], [], [4.4], [5.5]]

See :py:obj:`ak.firsts` to invert this function.

