两个带有水平连接图表的标题

如何解决两个带有水平连接图表的标题

我想连接两个图表，然后美化生成的组合图表（添加一些漂亮的背景）。这里的一件重要事情是尽量保留两个图表的标题。

当我尝试这样做时，我要么得到只有一个标题的美化组合图表，要么出现错误：ValueError: Objects with "background" attribute cannot be used within HConcatChart. Consider defining the background attribute in the HConcatChart object instead.

以下是我尝试过的一些虚拟代码片段。

尝试 #1，它只产生一个标题：

import altair as alt
from vega_datasets import data

source = data.cars()

line = alt.Chart(source).mark_line().encode(
    x='Year',y='mean(Miles_per_gallon)'
)

band = alt.Chart(source).mark_errorband(extent='ci').encode(
    x='Year',y=alt.Y('Miles_per_gallon',title='Miles/gallon'),)

combined = band | line
combined
combined.properties(background = '#f9f9f9',title = alt.TitleParams(text = 'General title',subtitle = ['Subtitle'],font = 'Ubuntu Mono',fontSize = 22,color = '#3E454F',subtitleFont = 'Ubuntu Mono',subtitleFontSize = 16,subtitleColor = '#3E454F')
                  )

尝试 #2 会产生值错误：

line2 = line.properties(background = '#f9f9f9',title = alt.TitleParams(text = 'General title 1',subtitleColor = '#3E454F')
                  )

band2 = band.properties(background = '#f9f9f9',title = alt.TitleParams(text = 'General title 2',subtitleColor = '#3E454F')
                  )
line2 | band2

有没有办法实现我想要的？或者 altair 还不允许这样做？

解决方法

您可以在单个图表上指定标题，在组合图表上指定背景：

line2 = line.properties(
                    title = alt.TitleParams(text = 'General title 1',subtitle = ['Subtitle'],font = 'Ubuntu Mono',fontSize = 22,color = '#3E454F',subtitleFont = 'Ubuntu Mono',subtitleFontSize = 16,subtitleColor = '#3E454F')
                  )

band2 = band.properties(
                    title = alt.TitleParams(text = 'General title 2',subtitleColor = '#3E454F')
                  )

combined = band2 | line2
combined.properties(background = '#f9f9f9')