jq - How to iterate through keys of different names - json

Question

I've got JSON that looks like this
{
"keyword1": {
"identifier1": 16
},
"keyword2": {
"identifier2": 16
}
}
and I need to loop through the keywords to get the identifiers (not sure if I'm using the right terminology here). Seems pretty simple, but because the keywords are all named different, I don't know how to handle that.

Answer 1

The original tag for this question was jq so here is a jq solution:
.[] | keys[]
For example, with the input as shown in the question:
$ jq '.[] | keys[]' input.json
"identifier1"
"identifier2"
To retrieve the key names in the order they appear in the JSON object, use keys_unsorted.

Answer 2

I'd think something along these lines would work well:
jq '. | to_entries | .[].key'
see https://stedolan.github.io/jq/manual/#to_entries,from_entries,with_entries
or if you wanted to get the values from a variable:
JSON_DATA={main:{k1:v1,k2:v2}}
result=$(jq -n "$JSON_DATA" | jq '.main | to_entries | .[].value' --raw-output)
echo $result
##outputs: v1 v2

Answer 3

I came here hoping to sort out a bunch of keys from my JSON, I found two features handy. There are three functions "to_entries", "from_entries", and "with_entries". You can filter the values by key or value, like so:
JSON_DATA='
{
"fields": {
"first": null,
"second": "two",
"third": "three"
}
}
'
echo "$JSON_DATA" | jq '{fields: .fields | with_entries(select(.value != null and .key != "third")) }'
Output:
{
"fields": {
"second": "two"
}
}

Answer 4

simpler solution - just treat internal hash as a new hash and add one more filter. The query that helped me:
$ docker network inspect bridge|jq '.[].Containers'
{
"35c9e1273c43db01c45b5f43f6999d04c18beff3996ea09fb8b87a8b635c38ff": {
"Name": "nginx",
"EndpointID": "a6e788d6f90eb14df2321a2eb02517f0862c1fe7fe50c02f2b8c103c0c79cb6b",
"MacAddress": "02:42:ac:11:00:02",
"IPv4Address": "172.17.0.2/16",
"IPv6Address": ""
},
"b46c157cec243969f9227251dfd6fa65b7a904e145df80a63f79d4dc8b281355": {
"Name": "sweet_gates",
"EndpointID": "a600d9c1ee35b9f7db31249ae8f589c202e0b260e10a394757a88bfd66b5b42f",
"MacAddress": "02:42:ac:11:00:03",
"IPv4Address": "172.17.0.3/16",
"IPv6Address": ""
}
}
As I needed only couple of fields, add to above .json one more query:
$ docker network inspect bridge|jq -jr '.[].Containers[]|.IPv4Address, "\t", .Name, "\n"'
172.17.0.2/16 nginx
172.17.0.3/16 sweet_gates