:orphan:
:html_theme.sidebar_secondary.remove:
.. This document is auto-generated by the altair-gallery extension. Do not modify directly.
.. _gallery_bar_with_rolling_mean:
Bar Chart with Rolling Mean
---------------------------
A bar chart overlayed with a rolling mean. In this example the average of values over the previous decade is displayed as a line.
.. altair-plot::
:remove-code:
import altair as alt
from vega_datasets import data
source = data.wheat()
bar = alt.Chart(source).mark_bar().encode(
x='year:O',
y='wheat:Q'
)
line = alt.Chart(source).mark_line(color='red').transform_window(
# The field to average
rolling_mean='mean(wheat)',
# The number of values before and after the current value to include.
frame=[-9, 0]
).encode(
x='year:O',
y='rolling_mean:Q'
)
(bar + line).properties(width=600)
# No channel encoding options are specified in this chart
# so the code is the same as for the method-based syntax.
.. tab-set::
.. tab-item:: Method syntax
:sync: method
.. code:: python
import altair as alt
from vega_datasets import data
source = data.wheat()
bar = alt.Chart(source).mark_bar().encode(
x='year:O',
y='wheat:Q'
)
line = alt.Chart(source).mark_line(color='red').transform_window(
# The field to average
rolling_mean='mean(wheat)',
# The number of values before and after the current value to include.
frame=[-9, 0]
).encode(
x='year:O',
y='rolling_mean:Q'
)
(bar + line).properties(width=600)
.. tab-item:: Attribute syntax
:sync: attribute
.. code:: python
import altair as alt
from vega_datasets import data
source = data.wheat()
bar = alt.Chart(source).mark_bar().encode(
x='year:O',
y='wheat:Q'
)
line = alt.Chart(source).mark_line(color='red').transform_window(
# The field to average
rolling_mean='mean(wheat)',
# The number of values before and after the current value to include.
frame=[-9, 0]
).encode(
x='year:O',
y='rolling_mean:Q'
)
(bar + line).properties(width=600)
# No channel encoding options are specified in this chart
# so the code is the same as for the method-based syntax.