jq-将其他JSON对象提取到新数组中 [英] jq - extract additional JSON object into new array

问题描述

我有一些JSON.看起来像这样:

I have some JSON. It looks like this:

{
"Volumes": [
    {
        "Attachments": [
            {
                "VolumeId": "vol-11111111",
                "State": "attached",
                "DeleteOnTermination": false,
                "Device": "/dev/sdz"
            }
        ],
        "Tags": [
            {
                "Value": "volume1",
                "Key": "Name"
            },
            {
                "Value": "00:00",
                "Key": "Start"
            },
            {
                "Value": "00:20",
                "Key": "Finish"
            },
            {
                "Value": "2",
                "Key": "Period"
            }
        ],
        "VolumeId": "vol-11111111"
    },
    {
        "Attachments": [
            {
                "VolumeId": "vol-22222222",
                "State": "attached",
                "DeleteOnTermination": false,
                "Device": "/dev/sdz"
            }
        ],
        "Tags": [
            {
                "Value": "volume2",
                "Key": "Name"
            },
            {
                "Value": "00:00",
                "Key": "Start"
            },
            {
                "Value": "00:20",
                "Key": "Finish"
            },
            {
                "Value": "2",
                "Key": "Period"
            }
        ],
        "VolumeId": "vol-22222222"
    },
    {
        "Attachments": [
            {
                "VolumeId": "vol-333333333",
                "State": "attached",
                "DeleteOnTermination": false,
                "Device": "/dev/sdz"
            }
        ],
        "Tags": [
            {
                "Value": "volume3",
                "Key": "Name"
            },
            {
                "Value": "00:00",
                "Key": "Start"
            },
            {
                "Value": "00:20",
                "Key": "Finish"
            },
            {
                "Value": "2",
                "Key": "Period"
            }
        ],
        "VolumeId": "vol-33333333"
    }
]
}

使用jq，我可以提取以下信息:

Using jq, I am able to extract the following information:

VolumeId，完成，开始，句点

VolumeId,Finish,Start,Period

使用jq命令

cat json | jq -r '[.Volumes[]|({VolumeId}+(.Tags|from_entries))|{VolumeId,Finish,Start,Period}]'

[
  {
    "VolumeId": "vol-11111111",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2"
  },
  {
    "VolumeId": "vol-22222222",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2"
  },
  {
    "VolumeId": "vol-33333333",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2"
  }
]

---

所有这些都很好.但是，我需要额外提取.Attachments.Device.我正在寻找类似于以下每个数组的输出:

---

All this works fine. However I have the need to additional extract .Attachments.Device. I am looking for output for each array similar to:

 [
  {
    "VolumeId": "vol-11111111",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2",
    "DeviceId": "/dev/sdz"
  },
  {
    "VolumeId": "vol-22222222",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2",
    "DeviceId": "/dev/sdz"
  },
  {
    "VolumeId": "vol-33333333",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2",
    "DeviceId": "/dev/sdz"
  }
]

但是，我无法弄清楚如何做到这一点而不会出错.对我而言，最合乎逻辑的方法是执行以下操作:

However I can't figure out how to do this without getting an error. The most logical approach for me would be to do something like:

cat json | jq -r '[.Volumes[]|({VolumeId}+(.Attachments|from_entries)+(.Tags|from_entries))|{VolumeId,Finish,Start,Period,DeviceId}]'

但是我得到了错误:

jq: error (at <stdin>:91): Cannot use null (null) as object key

任何帮助弄清楚我在做什么不正确以及如何解决它，将不胜感激.

Any help figuring out what I am not doing correct and how to fix it would be greatly appreciated.

谢谢

推荐答案

最终，问题在于您无法在Attachments数组上使用from_entries. from_entries使用键/值对对象数组来创建具有这些值的对象.但是，您没有键/值对，但是有对象.如果您只是尝试将它们组合，则应使用add.

Ultimately, the problem is that you're using from_entries on the Attachments array when it wouldn't work. from_entries takes an array of key/value pair objects to create an object with those values. However, you don't have key/value pairs, but objects. If you're just trying to combine them, you should use add.

此外，没有名为DeviceId的属性，它是Device.如果要选择Device属性并将其获取为DeviceId，则需要提供正确的名称.

Also, there is no property named DeviceId, it's Device. If you want to select the Device property and get it as DeviceId, you need to provide the correct name.

.Volumes | map(
    ({ VolumeId } + (.Attachments | add) + (.Tags | from_entries))
      | { VolumeId, Finish, Start, Period, DeviceId: .Device }
)

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