jq: selecting a subset of keys from an object

Question

Given an input json string of keys from an array, return an object with only the entries that had keys in the original object and in the input array.

I have a solution but I think that it isn't elegant ({($k):$input[$k]} feels especially clunky...) and that this is a chance for me to learn.

jq -n '{"1":"a","2":"b","3":"c"}'   \     | jq --arg keys '["1","3","4"]' \     '. as $input       | ( $keys | fromjson )      | map( . as $k           | $input           | select(has($k))           | {($k):$input[$k]}           )      | add' 

Any ideas how to clean this up?

I feel like Extracting selected properties from a nested JSON object with jq is a good starting place but i cannot get it to work.

Answer 1

solution with inside check:

jq 'with_entries(select([.key] | inside(["key1", "key2"])))' 

Answer 2

You can use this filter:

with_entries(     select(         .key as $k | any($keys | fromjson[]; . == $k)     ) )