如何用jq按国家及层级值分组数组并封装实体？

需求说明 #

给定输入JSON，需完成以下处理：

• 按country字段分组
• 将条目分为两类：包含H1/H2层级的为一组，包含H3/H4层级的为另一组
• 每组内的id和level字段封装到名为entities的数组中

输入JSON #

{
  "hits": [
    {
      "country": "PT",
      "level": "H2",
      "id": "id1"
    },
    {
      "country": "PT",
      "level": "H1",
      "id": "id2"
    },
    {
      "country": "CZ",
      "level": "H2",
      "id": "id3"
    },
    {
      "country": "IT",
      "level": "H2",
      "id": "id4"
    },
    {
      "country": "PT",
      "level": "H3",
      "id": "id5"
    },
    {
      "country": "PT",
      "level": "H3",
      "id": "id6"
    },
    {
      "country": "PT",
      "level": "H4",
      "id": "id7"
    }
  ]
}

期望输出 #

{
  "hits": [
    {
      "country": "PT",
      "entities": [
        {
          "id": "id2",
          "level": "H1"
        },
        {
          "id": "id1",
          "level": "H2"
        }
      ]
    },
    {
      "country": "CZ",
      "entities": [
        {
          "id": "id3",
          "level": "H2"
        }
      ]
    },
    {
      "country": "IT",
      "entities": [
        {
          "id": "id4",
          "level": "H2"
        }
      ]
    },
    {
      "country": "PT",
      "entities": [
        {
          "id": "id5",
          "level": "H3"
        },
        {
          "id": "id6",
          "level": "H3"
        },
        {
          "id": "id7",
          "level": "H4"
        }
      ]
    }
  ]
}

JQ解决方案 #

执行以下JQ命令即可实现需求：

.hits
| group_by(.country)
| map(
    group_by(
        if .level | IN("H1", "H2") then "high" else "low" end
    )
    | map({
        country: first.country,
        entities: map({id, level})
    })
)
| flatten
| {hits: .}

命令分步解释 #

• .hits：提取顶层的hits数组，作为后续操作的数据源
• group_by(.country)：将所有条目按country字段分组，得到每个国家对应的条目数组
• 内层group_by(...)：对每个国家的条目数组，进一步按层级分类：判断level是否为H1或H2，是则归为"high"组，否则归为"low"组，每个国家最多生成两个分组
• map({country: first.country, entities: map({id, level})})：将每个分组转换为目标格式，country取分组内第一个条目的值，entities是分组内每个条目仅保留id和level字段后的数组
• flatten：将嵌套的数组结构展平为一维数组，确保最终hits是单层数组
• {hits: .}：将处理后的数组包装回顶层的hits对象，匹配期望的输出结构

内容的提问来源于stack exchange，提问作者António