Altair-如何将数据框列显示为带有相应颜色的标签 [英] Altair - how to show a dataframe column as label with its respective color

问题描述

我试图在面积图上显示我从数据框中选择的列名称作为标签，以及使用Altair时的相应颜色。

I am trying to show on an Area Chart the column name(s) I selected from a Dataframe as label, along with its respective color using Altair.

问题是，每个这样做的时候，图表消失了，我无法根据十六进制代码列表自定义颜色。

The problem is that every time I do it, the chart disappear and I can't customize the colors based on a list of hex Codes.

有什么方法可以实现这一目标？

Is there any way to achieve this?

import altair as alt
import pandas as pd
import os


df = {
    'Month': ['Apr', 'May'],
    'Status': ['Working', 'Complete'],
    'Revenue': [1000, 2000],
    'Profit': [500, 600]
}

df = pd.DataFrame(df)

hexList = [
    '#002664', '#72BF44', '#EED308', '#5E6A71', '#7C9DBE', '#F47920', '#1C536E', '#2D580C',
]

xSelected = 'Status'
ySelected = ['Revenue']

chartsList = []

chart = alt.Chart(df).mark_area().encode(
    x=xSelected,
    y=ySelected[0],
    #color=alt.Color(f'{xSelected}:N'), ### **==> this gives me the labels I neeed, but no chart is plotted**
    color=alt.value(f'{hexList[0]}'), ### **==> this gives me the chart with the color I want, but without the labels I need**
    tooltip=ySelected
)

mainDir = os.path.dirname(__file__)
filePath = os.path.join(mainDir, 'altairChart.html')
chart.save(filePath)

推荐答案

图表使用颜色编码消失的原因是，每个颜色组仅包含一个点，并且该点下的区域的宽度为零，因此显示为空。

The reason the chart disappears with a color encoding is because your color groups each contain only a single point, and the area under a point has zero width and thus appears empty. Perhaps a bar chart would be a better fit?

chart = alt.Chart(df).mark_bar().encode(
    x=xSelected,
    y=ySelected[0],
    color=alt.Color(f'{xSelected}:N'),
    tooltip=ySelected
)

这篇关于Altair-如何将数据框列显示为带有相应颜色的标签的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！