使用 jq 将 json 转换为 csv，数组嵌套在数组中答案

【问题标题】：Convert json to csv using jq, with array nested within array使用 jq 将 json 转换为 csv，数组嵌套在数组中
【发布时间】：2021-02-27 17:26:32
【问题描述】：

如何展平这个 json 数组并使用 jq 写入 csv 文件，以便每一行包含所有字段，即

我是 jq 的新手，但从这个开始，它不会捕获内部嵌套数组

jq -r '(.[0] | keys_unsorted) as $keys | $keys, map([.[ $keys[] ]])[]'

[
   {
      "name":"PM2.5",
      "unit":"ug/m3",
      "values":[
         {
            "timestamp":"2020-11-16T13:10:21.135Z",
            "value":3.696
         },
         {
            "timestamp":"2020-11-16T13:10:31.649Z",
            "value":3.696
         },
         {
            "timestamp":"2020-11-16T13:10:42.35Z",
            "value":3.696
         },
         {
            "timestamp":"2020-11-16T13:10:52.953Z",
            "value":3.696
         }
      ]
   },
   {
      "name":"PM10",
      "unit":"ug/m3",
      "values":[
         {
            "timestamp":"2020-11-16T13:10:21.135Z",
            "value":7.596
         },
         {
            "timestamp":"2020-11-16T13:10:31.649Z",
            "value":7.596
         },
         {
            "timestamp":"2020-11-16T13:10:42.35Z",
            "value":7.596
         },
         {
            "timestamp":"2020-11-16T13:10:52.953Z",
            "value":7.596
         }
      ]
   }
]

到一个csv如下：

"name", "unit", "timestamp", "value"
"PM2.5", "ug/m3", "2020-11-16T13:10:21.135Z", 3.696
"PM2.5", "ug/m3", "2020-11-16T13:10:31.649Z", 3.696
"PM2.5", "ug/m3", "2020-11-16T13:10:42.35Z", 3.696
"PM2.5", "ug/m3", "2020-11-16T13:10:52.953Z", 3.696  
"PM10", "ug/m3", "2020-11-16T13:10:21.135Z", 7.596
"PM10", "ug/m3", "2020-11-16T13:10:31.649Z", 7.596
"PM10", "ug/m3", "2020-11-16T13:10:42.35Z", 7.596
"PM10", "ug/m3", "2020-11-16T13:10:52.953Z", 7.596

【问题讨论】：

@Shawn 是的，很抱歉试图添加，但被堆栈溢出标记为 for being mostly code，我现在添加了一个示例
@Shawn 是的，你是对的，这是最小的例子

标签： json nested export-to-csv jq

【解决方案1】：

$ jq -r '
  [["name","unit","timestamp","value"]], 
   [ .[] 
     | [ .name, .unit ] + 
       (.values[] | [.timestamp,.value]) ] 
  | .[] 
  | @csv' input.json 
"name","unit","timestamp","value"
"PM2.5","ug/m3","2020-11-16T13:10:21.135Z",3.696
"PM2.5","ug/m3","2020-11-16T13:10:31.649Z",3.696
"PM2.5","ug/m3","2020-11-16T13:10:42.35Z",3.696
"PM2.5","ug/m3","2020-11-16T13:10:52.953Z",3.696
"PM10","ug/m3","2020-11-16T13:10:21.135Z",7.596
"PM10","ug/m3","2020-11-16T13:10:31.649Z",7.596
"PM10","ug/m3","2020-11-16T13:10:42.35Z",7.596
"PM10","ug/m3","2020-11-16T13:10:52.953Z",7.596

构建一个数组数组，每行一个，包括标题行，然后将它们全部格式化为 CSV 记录。

【讨论】：

感谢不是我所追求的输出格式，我已经改进了问题
这可以通过删除最后的 .[] 来简化（并提高效率），如下所示：'["name", "unit", "timestamp", "value"] , (.[] | [.name, .unit] + (.values[] | [.timestamp, .value])) | @csv'