jq - convert a list of objects into a summarized object

Question

I have a JSON data like this:

[
  {
    "tone_id": "anger",
    "score": 0.012,
    "tone_name": "Anger"
  },
  {
    "tone_id": "disgust",
    "score": 0.002,
    "tone_name": "Disgust"
  },
  {
    "tone_id": "fear",
    "score": 0.14,
    "tone_name": "Fear"
  },
  {
    "tone_id": "joy",
    "score": 0.42,
    "tone_name": "Joy"
  }
]

I want to convert it into something like the following using jq:

{
  "anger": 0.012,
  "disgust": 0.002,
  "fear": 0.14,
  "joy": 0.42
}

Best I could do is:

cat result.json | jq '.[] | { (.tone_id): .score }'

which gave the following:

{
  "anger": 0.012
}
{
  "disgust": 0.002
}
{
  "fear": 0.14
}
{
  "joy": 0.42
}

I know I can easily do this using other methods. Just wanted to know if it's possible using jq one-liner?

show, how the potential 3rd and 4th objects should be processed? Extend your input array — RomanPerekhrest, Nov 29 '17 at 11:19
It's just a list of `tone_id` and their respective `score`s... I want as many keys in my final object as the number of elements in the original list. — munikarmanish, Nov 29 '17 at 11:21
@RomanPerekhrest Exactly how the 1st and 2nd objects are processed. Extract `tone_id` and `score` and make them key, value respectively in the final output. I've added more concrete example above. — munikarmanish, Nov 29 '17 at 11:30

peak · Accepted Answer · 2017-11-29T13:50:04.047

9

A single-invocation one-liner:

 jq 'map( {(.tone_id): .score} ) | add'

(You could also wrap square brackets around .[] | { (.tone_id): .score } before passing to add — the two approaches are equivalent.)

edited Nov 29 '17 at 13:50

answered Nov 29 '17 at 12:37

peak

105,803
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score 1 · Answer 2 · answered Nov 29 '17 at 15:24

1

You can use from_entries:

jq '[.[] | {key: .tone_id, value: .score}] | from_entries' tmp.json
# or jq 'map({key: .tone_id, value: .score}) | from_entries' tmp.json

although in this case I don't see anything to recommend it over @peak's add solution.

answered Nov 29 '17 at 15:24

chepner

497,756
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score 0 · Answer 3 · answered Nov 29 '17 at 11:57

0

With reduce function:

jq 'reduce .[] as $o ({}; .[$o["tone_id"]] = $o["score"])' result.json

The output:

{
  "anger": 0.012,
  "disgust": 0.002,
  "fear": 0.14,
  "joy": 0.42
}

answered Nov 29 '17 at 11:57

RomanPerekhrest

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jq - convert a list of objects into a summarized object

3 Answers3