Bar Chart with Negative Values

This example shows a bar chart with both positive and negative values.

Method syntax

import altair as alt
from vega_datasets import data

source = data.us_employment()

predicate = alt.datum.nonfarm_change > 0
color = alt.when(predicate).then(alt.value("steelblue")).otherwise(alt.value("orange"))

alt.Chart(source).mark_bar().encode(
    x="month:T",
    y="nonfarm_change:Q",
    color=color
).properties(width=600)

Attribute syntax

import altair as alt
from vega_datasets import data

source = data.us_employment()

predicate = alt.datum.nonfarm_change > 0
color = alt.when(predicate).then(alt.value("steelblue")).otherwise(alt.value("orange"))

alt.Chart(source).mark_bar().encode(
    x="month:T",
    y="nonfarm_change:Q",
    color=color
).properties(width=600)
# No channel encoding options are specified in this chart
# so the code is the same as for the method-based syntax.