Question 223822 in Json Question posted in
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Json – Group and Sum value with JQ

I’ve got a file with these jsons:

{"count":42,"day":"2023-06-22","id":"123"}
{"count":12,"day":"2023-06-22","id":"456"}
{"count":23,"day":"2023-06-23","id":"123"}
{"count":44,"day":"2023-06-23","id":"789"}
{"count":65,"day":"2023-06-21","id":"456"}

Actually I don’t care about the day and want to group my records by id and sum the count. Expected result:

{"id":"123","count":65}
{"id":"456","count":77}
{"id":"789","count":44}

How would I achieve this with JQ?

Tags:

2

Answers


  1. 0

    Use group_by to group the objects.

    jq -cs 'group_by(.id)[] | {id: .[0].id, count: map(.count) | add}' < file.json
    • -s wraps the whole input into a large array so you can process all the objects instead of iterating them one by one;
    • -c compresses the output so it looks like the desired one.
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  2. 0

    If the input is large, and you don’t want to --slurp (or -s) all items into memory (only effective if there are at least some duplicate IDs), you can take a reduce-based approach which iterates over the inputs collecting only the aggregated values:

    jq -cn '
  reduce inputs as {$count, $id} ({}; .[$id] += $count)
  | to_entries[] | {id: .key, count: .value}
'

    {"id":"123","count":65}
{"id":"456","count":77}
{"id":"789","count":44}

    Demo

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