刷选散点图以在表格中展示数据

一个展示汽车数据集的散点图，其中包含马力（horsepower）、每加仑英里数（MPG）和产地（origin）的数据表。这些表格会根据散点图上的选择进行更新。

方法语法

import altair as alt
from vega_datasets import data

source = data.cars()

# Brush for selection
brush = alt.selection_interval()

# Scatter Plot
points = alt.Chart(source).mark_point().encode(
    x='Horsepower:Q',
    y='Miles_per_Gallon:Q',
    color=alt.when(brush).then(alt.value("steelblue")).otherwise(alt.value("grey"))
).add_params(brush)

# Base chart for data tables
ranked_text = alt.Chart(source).mark_text(align='right').encode(
    y=alt.Y('row_number:O').axis(None)
).transform_filter(
    brush
).transform_window(
    row_number='row_number()'
).transform_filter(
    alt.datum.row_number < 15
)

# Data Tables
horsepower = ranked_text.encode(text='Horsepower:N').properties(
    title=alt.Title(text='Horsepower', align='right')
)
mpg = ranked_text.encode(text='Miles_per_Gallon:N').properties(
    title=alt.Title(text='MPG', align='right')
)
origin = ranked_text.encode(text='Origin:N').properties(
    title=alt.Title(text='Origin', align='right')
)
text = alt.hconcat(horsepower, mpg, origin) # Combine data tables

# Build chart
alt.hconcat(
    points,
    text
).resolve_legend(
    color="independent"
).configure_view(
    stroke=None
)

属性语法

import altair as alt
from vega_datasets import data

source = data.cars()

# Brush for selection
brush = alt.selection_interval()

# Scatter Plot
points = alt.Chart(source).mark_point().encode(
    x='Horsepower:Q',
    y='Miles_per_Gallon:Q',
    color=alt.when(brush).then(alt.value("steelblue")).otherwise(alt.value("grey"))
).add_params(brush)

# Base chart for data tables
ranked_text = alt.Chart(source).mark_text(align='right').encode(
    y=alt.Y('row_number:O', axis=None)
).transform_filter(
    brush
).transform_window(
    row_number='row_number()'
).transform_filter(
    alt.datum.row_number < 15
)

# Data Tables
horsepower = ranked_text.encode(text='Horsepower:N').properties(
    title=alt.Title(text='Horsepower', align='right')
)
mpg = ranked_text.encode(text='Miles_per_Gallon:N').properties(
    title=alt.Title(text='MPG', align='right')
)
origin = ranked_text.encode(text='Origin:N').properties(
    title=alt.Title(text='Origin', align='right')
)
text = alt.hconcat(horsepower, mpg, origin) # Combine data tables

# Build chart
alt.hconcat(
    points,
    text
).resolve_legend(
    color="independent"
).configure_view(
    stroke=None
)