"""
Aggregate Bar Chart
-----------------
This example is a bar chart showing the US population distribution of age groups in 2000..
"""
import altair as alt
from vega_datasets import data
source = data.population()
chart = alt.Chart(source).mark_bar().encode(
x=alt.X('sum(people):Q', axis=alt.Axis(title='population')),
y=alt.Y('age:O', scale=alt.Scale(rangeStep=17)))
chart.transform = [{"filter": "datum.year == 2000"}]
"""
Simple Highlighted Bar Chart
============================
This example shows a basic bar chart with a single bar singled out for a highlight.
"""
# category: bar charts
import altair as alt
from vega_datasets import data
population = data.population()
alt.Chart(population).mark_bar().encode(
x="year:O",
y="sum(people):Q",
# The highlight will be set on the result of a conditional statement
color=alt.condition(
alt.datum.year == 1970, # If the year is 1970 this test returns True,
alt.value('orange'), # which sets the bar orange.
alt.value(
'steelblue') # And if it's not true it sets the bar steelblue.
))