ak.to_packed
------------

.. py:module: ak.to_packed

Defined in `awkward.operations.ak_to_packed <https://github.com/scikit-hep/awkward/blob/76cb66b946cbf2ae355bddf2530b323465395bae/src/awkward/operations/ak_to_packed.py>`__ on `line 15 <https://github.com/scikit-hep/awkward/blob/76cb66b946cbf2ae355bddf2530b323465395bae/src/awkward/operations/ak_to_packed.py#L15>`__.

.. py:function:: ak.to_packed(array, *, highlevel=True, behavior=None, attrs=None)


    :param array: Array-like data (anything :py:obj:`ak.to_layout` recognizes).
    :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

Returns an array with the same type and values as the input, but with packed inner structures:

- :py:obj:`ak.contents.NumpyArray` becomes C-contiguous (if it isn't already)
- :py:obj:`ak.contents.RegularArray` trims unreachable content
- :py:obj:`ak.contents.ListArray` becomes :py:obj:`ak.contents.ListOffsetArray`, making all list data contiguous
- :py:obj:`ak.contents.ListOffsetArray` starts at ``offsets[0] == 0``, trimming unreachable content
- :py:obj:`ak.contents.RecordArray` trims unreachable contents
- :py:obj:`ak.contents.IndexedArray` gets projected
- :py:obj:`ak.contents.IndexedOptionArray` remains an :py:obj:`ak.contents.IndexedOptionArray` (with simplified ``index``)
  if it contains records, becomes :py:obj:`ak.contents.ByteMaskedArray` otherwise
- :py:obj:`ak.contents.ByteMaskedArray` becomes an :py:obj:`ak.contents.IndexedOptionArray` if it contains records,
  stays a :py:obj:`ak.contents.ByteMaskedArray` otherwise
- :py:obj:`ak.contents.BitMaskedArray` becomes an :py:obj:`ak.contents.IndexedOptionArray` if it contains records,
  stays a :py:obj:`ak.contents.BitMaskedArray` otherwise
- :py:obj:`ak.contents.UnionArray` gets projected contents
- :py:obj:`ak.record.Record` becomes a record over a single-item :py:obj:`ak.contents.RecordArray`

.. rubric:: Example

>>> a = ak.Array([[1, 2, 3], [], [4, 5], [6], [7, 8, 9, 10]])
>>> b = a[::-1]
>>> b.layout
<ListArray len='5'>
    <starts><Index dtype='int64' len='5'>
        [6 5 3 3 0]
    </Index></starts>
    <stops><Index dtype='int64' len='5'>
        [10  6  5  3  3]
    </Index></stops>
    <content><NumpyArray dtype='int64' len='10'>
        [ 1  2  3  4  5  6  7  8  9 10]
    </NumpyArray></content>
</ListArray>

>>> c = ak.to_packed(b)
>>> c.layout
<ListOffsetArray len='5'>
    <offsets><Index dtype='int64' len='6'>[ 0  4  5  7  7 10]</Index></offsets>
    <content><NumpyArray dtype='int64' len='10'>
        [ 7  8  9 10  6  4  5  1  2  3]
    </NumpyArray></content>
</ListOffsetArray>

Performing these operations will minimize the output size of data sent to
:py:obj:`ak.to_buffers` (though conversions through Arrow, :py:obj:`ak.to_arrow` and
:py:obj:`ak.to_parquet`, do not need this because packing is part of that conversion).

See also :py:obj:`ak.to_buffers`.