ak.merge_union_of_records
-------------------------

.. py:module: ak.merge_union_of_records

Defined in `awkward.operations.ak_merge_union_of_records <https://github.com/scikit-hep/awkward/blob/4db797390ad1d0e182253449d8d80de32e1ebee8/src/awkward/operations/ak_merge_union_of_records.py>`__ on `line 22 <https://github.com/scikit-hep/awkward/blob/4db797390ad1d0e182253449d8d80de32e1ebee8/src/awkward/operations/ak_merge_union_of_records.py#L22>`__.

.. py:function:: ak.merge_union_of_records(array, axis=-1, *, highlevel=True, behavior=None, attrs=None)


    :param array: Array-like data (anything :py:obj:`ak.to_layout` recognizes).
    :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.contents.Content` subclass.
    :type highlevel: bool
    :param behavior: Custom :py:obj:`ak.behavior` for the output array, if
                 high-level.
    :type behavior: None or dict
    :param attrs: Custom attributes for the output array, if
              high-level.
    :type attrs: None or dict

Simplifies unions of records, e.g.

.. code-block:: python


    >>> array = ak.concatenate(([{"a": 1}], [{"b": 2}]))
    >>> array
    <Array [{a: 1}, {b: 2}] type='2 * union[{a: int64}, {b: int64}]'>

into records of options, i.e.

.. code-block:: python


    >>> ak.merge_union_of_records(array)
    <Array [{a: 1, b: None}, {a: None, ...}] type='2 * {a: ?int64, b: ?int64}'>

Missing records are preserved in the result, e.g.

.. code-block:: python


    >>> array = ak.concatenate(([{"a": 1}], [{"b": 2}, None]))
    >>> array
    <Array [{a: 1}, {b: 2}, None] type='3 * union[{a: int64}, ?{b: int64}]'>
    >>> ak.merge_union_of_records(array)
    <Array [{a: 1, b: None}, {...}, None] type='3 * ?{a: ?int64, b: ?int64}'>