CODEWITHSUNDEEP
jq
Logan Lee
Logan Lee

Reputation: 997

Passing variable in jq to filter with select fails

When I do this:

$ jq -cr '.arr[]|select(.id==-1)|.desc' <<<$'{"arr":[{"id":-1,"desc":"foo"},{"id":100}]}'
foo

works as expected.

But if I try to pass a variable in place of the index:

$ lookup=-1; jq -cr --arg l "$lookup" '.arr[]|select(.id==$l)|.desc' <<<$'{"arr":[{"id":-1,"desc":"foo"},{"id":100}]}'
no output

Doesn't produce output this time.

How to fix this so that it works with shell variable lookup?

Upvotes: 0

Views: 310

Answers (1)

pmf
pmf

Reputation: 36231

Use --argjson instead of --arg.

--arg l "$lookup" makes $l a string. With --argjson l "$lookup" it is interpreted as JSON, a number in this case, just as was 1 in .id==-1, your working example.

Or do an additional operation to use the tonumber flag to $l, indicating that you want the operation on a numeric equivalent of the string value passed. i.e. ($l|tonumber)

Upvotes: 1

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