2022-05-23 00:16:32 +04:00

28 lines
675 B
Python

"""
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.
"""
# category: bar charts
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)