.. This document is auto-generated by the altair-gallery extension. Do not modify directly.

.. _gallery_percentage_of_total:


Calculating Percentage of Total
-------------------------------
This chart demonstrates how to use a window transform to display data values
as a percentage of total values.


.. altair-plot::
    :code-below:

    
    import altair as alt
    import pandas as pd

    activities = pd.DataFrame({'Activity': ['Sleeping', 'Eating', 'TV', 'Work', 'Exercise'],
                               'Time': [8, 2, 4, 8, 2]})

    alt.Chart(activities).mark_bar().encode(
        alt.X('PercentOfTotal:Q', axis=alt.Axis(format='.0%')),
        y='Activity:N'
    ).transform_window(
        TotalTime='sum(Time)',
        frame=[None, None]
    ).transform_calculate(
        PercentOfTotal="datum.Time / datum.TotalTime"
    )


.. toctree::
   :hidden: