ak.firsts
---------

Defined in `awkward.operations.structure <https://github.com/scikit-hep/awkward-1.0/blob/80bbef0738a6b7928333d7c705ee1b359991de5b/src/awkward/operations/structure.py>`__ on `line 3055 <https://github.com/scikit-hep/awkward-1.0/blob/80bbef0738a6b7928333d7c705ee1b359991de5b/src/awkward/operations/structure.py#L3055>`__.

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


    :param array: Data from which to select the first elements from nested lists.
    :param axis: 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: 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

Selects the first element of each non-empty list and inserts None for each
empty list.

For example,

.. code-block:: python


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

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

