获取JSON对象的每个项目的最后N个元素 [英] Get last N elements for each item of a JSON object

问题描述

使用jq给出以下JSON对象，如何获取每个项目的最后两个元素?

Given the following JSON object, using jq, how to get the last two elements for each item?

我一直试图在jqplay.org的帮助下找到解决方案，但没有解决.从具有一致的键名的对象中获取值非常简单，但我无法解决这个问题.

I have been trying to find a solution with the help of jqplay.org but didn't get anywhere. While getting values out of objects having consistent key names is rather straightforward, I can't get my head around this.

输入:

{
  "foo": {
    "abc": { "key1": "value1" }, 
    "bcd": { "key1": "value1" },
    "cde": { "key1": "value1" },
    "def": { "key1": "value1" }, 
    "efg": { "key1": "value1" },
    "fgh": { "key1": "value1" }
  }, 
  "bar": {
    "ghi": { "key1": "value1" }
  }, 
  "qux": {
    "hij": { "key1": "value1" }, 
    "ijk": { "key1": "value1" },
    "jkl": { "key1": "value1" },
    "klm": { "key1": "value1" }
  }
  /* ... */
}

预期结果:

{
  "foo": {
    "efg": { "key1": "value1" },
    "fgh": { "key1": "value1" }
  }, 
  "bar": {
    "ghi": { "key1": "value1" }
  }, 
  "qux": {
    "jkl": { "key1": "value1" },
    "klm": { "key1": "value1" }
  }
  /* ... */
}

推荐答案

一个选项是使用delpaths删除除最后一个N(此处为2)之外的所有字段.但是，您需要将键名转换为路径表示形式.例如:

One option is to delete all fields but the last N (2 here) using delpaths. You need to convert key names to path representations though. E.g:

map_values(delpaths(keys_unsorted[:-2] | map([.])))

请参见 jqplay演示.

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