Vega-lite：如何自定义图例标签？

只需labelExpr在图例中提供，您就可以根据字段数据有条件地提供标签。请参考以下代码或编辑器中的图表

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "width": 560,
  "height": 200,
  "data": {
    "values": [
      {
        "title_type": "tv",
        "year_reference": "10-12-2012",
        "reference_count_total": 10
      },
      {
        "title_type": "movie",
        "year_reference": "10-12-2012",
        "reference_count_total": 10
      },
      {
        "title_type": "video",
        "year_reference": "10-12-2012",
        "reference_count_total": 10
      },
      {
        "title_type": "videoGame",
        "year_reference": "10-12-2012",
        "reference_count_total": 10
      }
    ]
  },
  "mark": {"type": "bar"},
  "encoding": {
    "x": {
      "field": "year_reference",
      "type": "temporal",
      "axis": {"title": "Year", "grid": true}
    },
    "y": {
      "field": "reference_count_total",
      "type": "quantitative",
      "axis": {"title": "References", "grid": true}
    },
    "color": {
      "field": "title_type",
      "scale": {
        "domain": ["tv", "movie", "video", "videoGame"],
        "range": ["#9e9ac8", "#74c476", "#a6761d", "#6baed6"]
      },
      "legend": {
        "labelExpr": "datum.label == 'tv' ? 'Tv' : datum.label == 'movie' ? 'Movie' :datum.label == 'video' ? 'Video' : 'Video Game'"
      },
      "title": "Reference Type"
    }
  }
}