CODEWITHSUNDEEP
pythonaltairvega-lite
viydanofyi
viydanofyi

Reputation: 59

Altair: Separate the color schemes in concatenated charts

For the example below I want to use green color scheme for exports and red for imports. When I separately create the charts everything is good, they get the color scheme I assign them. However, when I concat the charts both of them get the red scheme.

import pandas as pd
fruits = ['Apples', 'Pears', 'Nectarines', 'Plums', 'Grapes', 'Strawberries']
years = ["2015", "2016", "2017"]

exports = {'fruits' : fruits,
           '2015'   : [2, 1, 4, 3, 2, 4],
           '2016'   : [5, 3, 4, 2, 4, 6],
           '2017'   : [3, 2, 4, 4, 5, 3]}
imports = {'fruits' : fruits,
           '2015'   : [-1, 0, -1, -3, -2, -1],
           '2016'   : [-2, -1, -3, -1, -2, -2],
           '2017'   : [-1, -2, -1, 0, -2, -2]}

df_exp = pd.DataFrame(exports)
df_imp = pd.DataFrame(imports)

import altair as alt

cols_year_imp = df_imp.columns[1:]
cols_year_exp = df_exp.columns[1:]

imp = alt.Chart(df_imp).transform_fold(
    list(cols_year_imp)
).mark_bar(
    tooltip=True
).encode(
    x='value:Q',
    y='fruits:N',
    color=alt.Color('key:O', scale=alt.Scale(scheme='reds'))
)

exp = alt.Chart(df_exp).transform_fold(
    list(cols_year_exp)
).mark_bar(
    tooltip=True
).encode(
    x=alt.X('value:Q',title="Export"),
    y='fruits:N',
    color=alt.Color('key:O', scale=alt.Scale(scheme='greens', reverse=True)),
    order=alt.Order('key:O', sort='ascending')
)

# imp | exp
imp
exp
alt.hconcat(imp, exp)

output: https://i.sstatic.net/jFvu6.png

enter image description here

Upvotes: 6

Views: 1730

Answers (1)

joelostblom
joelostblom

Reputation: 48919

You can use resolve_scale on the concatenated figure:

alt.hconcat(imp, exp).resolve_scale(color='independent')

enter image description here

Upvotes: 7

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