jq select input based on values in array

Question

I have a list of country codes like FR, IT, DE and have been trying to figure out how to use this in a select statement. I was doing something like

cat stuff | jq -c '.[]| select(.country_iso3166_alpha2 == "US")'

But then my list grew to a large number of countries I want to match on. So I tried using IN since I'm using jq 1.6 and did something like this:

eu=("FR", "IT"); cat stuff | jq -c '.[]| select(.country_iso3166_alpha2 IN($eu)'

I've been reading the docs and looking at the cookbook but it's not making any sense to me. Thanks!

Answer 1

Unfortunately, jq does not understand bash arrays.

Things would probably be simplest if you can arrange to have your shell variable be a string representing a JSON array:

eu='["FR", "IT"]'
jq -n --argjson eu "$eu" '$eu'

Or if you prefer:

eu='["FR", "IT"]' jq -n 'env.eu | fromjson'

Another possibility would be to write your bash array into a file, and then slurp the file.

There are also many variants of the above....

Answer 2

You can use --argjson to pass the list to jq and IN to select the matching entries.

jq -c --argjson eu '["FR", "IT"]' '.[]| select(.country_iso3166_alpha2 | IN($eu[]))' <stuff

Broken out to show the individual parts:

jq -c \ 
    --argjson eu '["FR", "IT"]' \ 
    '.[]| select(.country_iso3166_alpha2 | IN($eu[]))' \ 
    <stuff

1. invoke jq with compact output
2. pass in the list of countries as a json array named "eu"
3. select using the IN operator, unpacking $eu[] to get its values
4. redirect the input file into jq