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

.. _gallery_us_population_over_time:


US Population Over Time
=======================
This chart visualizes the age distribution of the US population over time.
It uses a slider widget that is bound to the year to visualize the age
distribution over time.


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

    
    import altair as alt
    from vega_datasets import data

    source = data.population.url

    pink_blue = alt.Scale(domain=('Male', 'Female'),
                          range=["steelblue", "salmon"])

    slider = alt.binding_range(min=1900, max=2000, step=10)
    select_year = alt.selection_single(name="year", fields=['year'],
                                       bind=slider, init={'year': 2000})

    alt.Chart(source).mark_bar().encode(
        x=alt.X('sex:N', title=None),
        y=alt.Y('people:Q', scale=alt.Scale(domain=(0, 12000000))),
        color=alt.Color('sex:N', scale=pink_blue),
        column='age:O'
    ).properties(
        width=20
    ).add_selection(
        select_year
    ).transform_calculate(
        "sex", alt.expr.if_(alt.datum.sex == 1, "Male", "Female")
    ).transform_filter(
        select_year
    ).configure_facet(
        spacing=8
    )


.. toctree::
   :hidden: