JQ - Remove Duplicate Array Values - json

Question

Edited for better clarity
I am using the following jq query to extract the AWS ARN and associated protocols. However I only need the ARN to be listed once followed by the ports and protocols
my code is jq -r '.Listeners[] | (.LoadBalancerArn), (.Protocol)' and the results are
"arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde"
"HTTP"
"arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde"
"HTTP"
"arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde"
"HTTPS"
I have tried everything including unique, first, unique_by, select, contains, etc.. and the results are always "Cannot iterate over string" or number
Desired results
"arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde"
"HTTP"
"HTTP"
"HTTPS"
Sample JSON
{
"Listeners": [
{
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde",
"Port": 9090,
"Protocol": "HTTP"
},
{
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde",
"Port": 80,
"Protocol": "HTTP"
},
{
"LoadBalancerArn": "arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde",
"Port": 443,
"Protocol": "HTTPS"
}
]
}

Answer 1

Group by the common field and iterate over the groups, then output the common field of the first (which is the same for the whole group), and iterate again to output other fields from the same group:
jq -r '.Listeners | group_by(.LoadBalancerArn)[]
| .[0].LoadBalancerArn, .[].Protocol'
arn:aws:elasticloadbalancing:us-xxxx-1:123456789:loadbalancer/app/msword-123456789/20b73abcde
HTTP
HTTP
HTTPS
Demo

Answer 2

unique works on an array, so you'll need to create one with all the LoadBalancerArn first, then call unique and get the first of the remaining array:
.Listeners | map(.LoadBalancerArn) | unique | first

Answer 3

Does this produce what you expected ?
jq -r '.Listeners |
group_by(.LoadBalancerArn)[] |
first |
"\(.LoadBalancerArn) \(.Protocol)"
' input.json

Answer 4

You say you want the ARN listed once, followed by the ports and protocols. You don't give such an example, so it's unclear whether there might be multiple different ARNs between the items in the array of listeners. Let's assume that there might well be multiple different ARNs, and for that reason I'll use slightly different test data:
{
"Listeners": [
{
"LoadBalancerArn": "arn:example:BLUE",
"Port": 9090,
"Protocol": "HTTP"
},
{
"LoadBalancerArn": "arn:example:GOLD",
"Port": 80,
"Protocol": "HTTP"
},
{
"LoadBalancerArn": "arn:example:GOLD",
"Port": 443,
"Protocol": "HTTPS"
}
]
}
group_by is the JQ function for collecting together all the items in an array that share a particular value for some expression. So you could use
.Listeners|group_by(.LoadBalancerArn)
to get an array of arrays of objects, where all of the objects in each inner array has the same value of LoadBalancerArn:
[
[
{
"LoadBalancerArn": "arn:example:BLUE",
"Port": 9090,
"Protocol": "HTTP"
}
],
[
{
"LoadBalancerArn": "arn:example:GOLD",
"Port": 80,
"Protocol": "HTTP"
},
{
"LoadBalancerArn": "arn:example:GOLD",
"Port": 443,
"Protocol": "HTTPS"
}
]
]
From there you can safely pick out the ARN from the first object in each list, knowing that the rest must have the same value:
.Listeners|group_by(.LoadBalancerArn)[](first|{LoadBalancerArn})+{Listeners:map(del(.LoadBalancerArn))}
{
"LoadBalancerArn": "arn:example:BLUE",
"Listeners": [
{
"Port": 9090,
"Protocol": "HTTP"
}
]
}
{
"LoadBalancerArn": "arn:example:GOLD",
"Listeners": [
{
"Port": 80,
"Protocol": "HTTP"
},
{
"Port": 443,
"Protocol": "HTTPS"
}
]
}