Altair Brushing#
import altair as alt
import pandas as pd
import panel as pn
import panel_material_ui as pmui
pn.extension('vega')
This example demonstrates how to leverage the brushing/linked-selections support in the Vega pane to update a table.
df = pd.read_json("https://raw.githubusercontent.com/vega/vega/master/docs/data/penguins.json")
brush = alt.selection_interval(name='brush') # selection of type "interval"
chart = alt.Chart(df).mark_point().encode(
x=alt.X('Beak Length (mm):Q', scale=alt.Scale(zero=False)),
y=alt.Y('Beak Depth (mm):Q', scale=alt.Scale(zero=False)),
color=alt.condition(brush, 'Species:N', alt.value('lightgray'))
).properties(
width=300,
height=300
).add_params(
brush
)
vega_pane = pn.pane.Vega(chart, debounce=10)
def filtered_table(selection):
if not selection:
return df.iloc[:0]
query = ' & '.join(
f'{crange[0]:.3f} <= `{col}` <= {crange[1]:.3f}'
for col, crange in selection.items()
)
return df.query(query)
description = pn.pane.Markdown(
'Select points on the plot and watch the linked table update.',
sizing_mode='stretch_width'
)
table = pn.pane.DataFrame(
pn.bind(filtered_table, vega_pane.selection.param.brush),
height=350,
sizing_mode="stretch_width",
)
output = pn.Row(vega_pane, table)
output
Served App#
if pn.state.served:
pmui.Page(
main=[description, output],
title="Altair Brushing"
).servable()