Vega Lite条形图添加配色方案后排序异常问题求助

问题原因 #

这个问题由Vega Lite的隐式聚合逻辑触发：仅配置x、y编码时，简写的sort: "-x"可以被正确识别为按x轴Toll值降序排列。但当你新增绑定Toll字段的定量color编码后，Vega Lite会启动隐式分组聚合逻辑，简写的"-x"排序规则会被覆盖，y轴默认切换为按「死因」字段的原生顺序（大多为字母序）排列，最终导致原有排序失效。

解决方案 #

将y轴配置中简写的"-x"排序规则替换为显式的全量排序配置，明确指定排序的依据字段、聚合方式和方向即可解决问题，修改后的完整配置如下：

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "width": 800,
  "height": 600,
  "title": "Biggest Killers",
  "data": {
    "url": "https://raw.githubusercontent.com/githubuser0099/Assignment2.1/main/Cause_Of_Death_v2.csv"
  },
  "mark": "bar",
  "encoding": {
    "x": {
      "field": "Toll",
      "type": "quantitative",
      "title": ""
    },
    "y": {
      "field": "Cause Of Death",
      "type": "nominal",
      "title": "",
      "sort": {"field": "Toll", "op": "sum", "order": "descending"}
    },
    "color": {
      "field": "Toll",
      "type": "quantitative",
      "scale": {"scheme": "reds"}
    }
  }
}

内容的提问来源于stack exchange，提问作者Programming 55