objectif

Créer des graphiques déclaratifs avec Altair.

code minimal

import altair as alt
import pandas as pd

df = pd.DataFrame({"x":[1,2,3], "y":[1,4,9]})
chart = alt.Chart(df).mark_line().encode(x="x", y="y")
print(isinstance(chart, alt.Chart))

utilisation

import altair as alt
import pandas as pd

df = pd.DataFrame({"x":[1,2,3], "y1":[1,4,9], "y2":[3,2,1]})
c1 = alt.Chart(df).mark_bar().encode(x="x", y="y1")
c2 = alt.Chart(df).mark_line(color="red").encode(x="x", y="y2")
combo = c1 + c2
print(isinstance(combo, alt.LayerChart))

variante(s) utile(s)

import altair as alt
import pandas as pd

df = pd.DataFrame({"cat":["a","b","c"], "v":[3,1,2]})
chart = alt.Chart(df).mark_bar().encode(x="cat", y="v")
print(chart.to_dict()["mark"]["type"])

notes

• Altair génère du JSON Vega-Lite; interactif en notebook.