查找时 Vega-lite 图表失败，聚合在转换中组合

Question

为什么这个同时使用查找转换和聚合转换的 Vega-lite 代码无法显示图表？这是一个模拟我在我的项目中尝试做的事情的小例子。

{
  "data": {    
          "values": [ 
            {"group": 1, "person": "Alan"},
            {"group": 1, "person": "George"},
            {"group": 1, "person": "Fred"},
            {"group": 2, "person": "Steve"},
            {"group": 2, "person": "Nick"},
            {"group": 2, "person": "Will"},
            {"group": 2, "person": "Cole"},
            {"group": 3, "person": "Rick"},
            {"group": 3, "person": "Tom"}
          ]},
  "transform": [
    {
      "lookup": "person",
      "from": {
        "data": {    
          "values": [
              {"name": "Alan", "_source": { "age": 10, "category": 5}},
              {"name": "Tom", "_source": { "age": 7, "category": 10}}
          ]},
        "key": "name",
        "fields": ["_source.age", "_source.category"]
      }
    },
    {"aggregate": 
      [{"op": "sum", "field": "_source.age", "as": "totalage"}], 
      "groupby": ["totalage", "_source.category"]}
  ],
  "mark": "bar",
  "encoding": {
    "x": {"field": "_source.category", "type": "ordinal"},
    "y": {"field": "totalage", "type": "quantitative"}
  }
}

但是这个使用查找转换但不使用聚合转换的 Vega-lite 代码能否成功显示图表？

{
  "data": {    
          "values": [ 
            {"group": 1, "person": "Alan"},
            {"group": 1, "person": "George"},
            {"group": 1, "person": "Fred"},
            {"group": 2, "person": "Steve"},
            {"group": 2, "person": "Nick"},
            {"group": 2, "person": "Will"},
            {"group": 2, "person": "Cole"},
            {"group": 3, "person": "Rick"},
            {"group": 3, "person": "Tom"}
          ]},
  "transform": [
    {
      "lookup": "person",
      "from": {
        "data": {    
          "values": [
              {"name": "Alan", "_source": { "age": 10, "category": 5}},
              {"name": "Tom", "_source": { "age": 7, "category": 10}}
          ]},
        "key": "name",
        "fields": ["_source.age", "_source.category"]
      }
    }
  ],
  "mark": "bar",
  "encoding": {
    "x": {"field": "_source.category", "type": "ordinal"},
    "y": {"field": "_source.age", "aggregate": "sum", "type": "quantitative"}
  }
}

Answer 1

groupby 中的复合字段未正确转义（我相信这是 vega-lite 中的错误）。作为解决方法，您可以手动转义它们，即 replace

"groupby": ["_source.category"]

与

"groupby": ["_source\.category"]

我已经在 vega/vega-lite#6606

报告了这个错误

查找时 Vega-lite 图表失败，聚合在转换中组合

Vega-lite chart fails when lookup, aggregate combined in transform

vega-lite