**Benchmark setup**

.. code-block:: python

    from pandas_vb_common import *
    
    rng = DateRange('1/1/2000', periods=10000, offset=datetools.Minute())
    rng = rng.view(Index)
    rng2 = rng[:-1]
    

**Benchmark statement**

.. code-block:: python

    rng.union(rng2)

**Performance graph**

.. image:: vbench/figures/index_datetime_union.png
   :width: 6in