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How do I extract only the first time a key/value pair exists in a json object in bash with jq

Can anyone help me using bash and jq to be able to filter this JSON down to only the first occurrence of the user.login for each item, with the highest submitted_at key. An endpoint is giving me back historical information and I only want the most up to date details for the response. Take for example this JSON

[
  {
    "user": {
      "login": "user1",
    },
    "state": "CHANGE_REQUESTED",
    "submitted_at": "2024-01-23T19:18:31Z",
  },
  {
    "user": {
      "login": "user1",
    },
    "state": "DISMISSED",
    "submitted_at": "2024-02-05T16:49:58Z",
  },
  {
    "user": {
      "login": "user1",
    },
    "state": "APPROVED"
    "submitted_at": "2024-02-06T19:18:31Z",
  },
  {
    "user": {
      "login": "user2",
    },
    "state": "APPROVED"
    "submitted_at": "2024-01-23T19:18:31Z",
  },
  {
    "user": {
      "login": "user2",
    },
    "state": "DISMISSED"
    "submitted_at": "2024-01-21T19:18:31Z",
  }
]

The result should be the following JSON with only the most recent duplicate of user.login that I can then loop over

[
  {
    "user": {
      "login": "user1",
    },
    "state": "APPROVED"
    "submitted_at": "2024-02-06T19:18:31Z",
  },
  {
    "user": {
      "login": "user2",
    },
    "state": "APPROVED"
    "submitted_at": "2024-01-23T19:18:31Z",
  }
]

After which I can loop through in bash to gather the information that I need from the object.

This may be answered already somewhere but I think I’m struggling to word the ask in a search engine to be able to get the desired result.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    In order to result in the JSON that I was expecting, I used the following jq statement.

    jq '. |= sort_by(.submitted_at) | reverse | unique_by(.user.login)' "$tmp_response_file_pr_reviews_request"

    This sorted the resulting array by it's submitted_at revered so that the highest date is at the top, and then using unique_by to filter down to only the first instance of each `user.login Key-Value pair in the array, resulting in what I needed.


  2. 0

    only the first occurrence of the user.login for each item, with the highest submitted_at key

    With group_by(.user.login) you can group together into subarrays all objects with the same .user.login value. Then, from each subarray, pick the one item with the highest .submitted_at value using max_by(.submitted_at). The final array can be created either using an array constructor […] and iterating over the groups using .[], or by re-using the grouping array and accessing the groups using a map.

    # Using an array constructor
[group_by(.user.login)[] | max_by(.submitted_at)]

# Using map
group_by(.user.login) | map(max_by(.submitted_at))

    Demo

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