jq select input based on values in array - jq

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

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

Answer 2

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....