Altair Brushing#
import altair as alt
import pandas as pd
import panel as pn
pn.extension('vega', template='fast')
pn.state.template.title = "Altair Brushing Example"
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)
pn.Column(
'Select points on the plot and watch the linked table update.',
sizing_mode='stretch_width'
).servable()
pn.Row(
vega_pane,
pn.Column(
pn.pane.DataFrame(
pn.bind(filtered_table, vega_pane.selection.param.brush)
),
height=350
)
).servable()