Question 109594 in Json Question posted in
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Json – Select values that match an element in bash array in JQ

I need to run a script where I have an array of ids, and a json that contains elements with these ids and more data. I need to filter/select the values that matches the ones in the array. For some reason, when running directly on bash I got good results with some of the things I’ve tried, but not when running with a script. Not sure if this may be relevant or I did something wrong when passing from one to the other

For example, if I have a json file like

[
 {
   "id": 1,
   "value": 10
 },   
 {
   "id": 2,
   "value": 100
 },
 {
   "id": 3,
   "value": 5
 },
 {
   "id": 4,
   "value": 17
 },
 {
   "id": 5,
   "value": 84
 }
]

And the following array:

IDS=(1 2 3 4)

I need to retrieve the values 10, 100, 5 and 17.

I’ve tried some ways:

VALUES=$(jq --argjson IDS "$IDS" '.[] | select( $IDS =~ .id ) | .value' file.json)
VALUES=$(jq --argjson IDS "$IDS" '.[] | select( ${IDS[*]} =~ .id ) | .value' file.json)
# I have certainty that IDS will always have 4 elements, no more no less
VALUES=$(jq --argjson IDS "$IDS" '.[] | select( .id == ${IDS[0]} | .id == ${IDS[1]} | .id == ${IDS[2]} | .id == ${IDS[3]} ) | .value' file.json)

In all cases I’m getting `unexpected INVALID_CHARACTER (Unix shell quoting issues?)

Also, on the last case, when I replaced the ${IDS[n]} for a hardcoded number, it worked fine. Yet, I won’t have the same numbers on each run, so I need that parametrized.

Any help would be great!

EDIT

Thanks everyone for the solutions. I kept the one I understood the most for now, but I’m really greatful with all

Tags:

4

Answers


  1. 0

    You’re looking for something like this:

    $ IDS=(1 2 3 4)
$ jq '.[] | select(IN(.id; $ARGS.positional[])) .value' file.json --jsonargs "${IDS[@]}"
10
100
5
17
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  2. 0

    Use --arg and then convert the Bash array to JSON integers:

    ($IDS | split(" ") | map(tonumber)) as $PIDS

    Combine that with select() and index():

    jq 
    --arg IDS "${IDS[*]}" 
    '($IDS | split(" ") | map(tonumber)) as $PIDS | 
        .[] | select([.id] | index($PIDS[])).value' 
input

    Gives:

    10
100
5
17
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  3. 0

    One approach is to create a map of acceptable IDs and then do lookups within it:

    ids=( 1 2 3 4 )

jq --arg idstr "${ids[*]}" '
  ([$idstr | split(" ")[] | {"key": ., "value": true}] | from_entries) as $idmap
  | .[] | select($idmap[.id | tostring]).value'
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  4. 0

    Alternatively, pass ids individual array elements as arguments to jq using --args "${ids[@]}" and read the values back into a bash array with mapfile:

    #!/usr/bin/env bash

ids=( 1 2 3 4 )

mapfile -t values < <(

jq '
  (
    [$ARGS.positional[] | {"key": ., "value": true}] |
    from_entries
  ) as $idmap |
  .[] |
  select($idmap[.id | tostring]).value' 
  input.json 
  --args "${ids[@]}" 
)

# Debug show content of values array
declare -p values

    Sample output:

    declare -a values=([0]="10" [1]="100" [2]="5" [3]="17")
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