til/jq/extract-a-list-of-values.md

Extract A List Of Values

jq can be used to extract a list of values from an array in a JSON file.

Consider the following JSON:

{
  "items": [
    { "id": 1, "name": "Liz Lemon" },
    { "id": 2, "name": "Pete Hornberger" },
    { "id": 3, "name": "Tracy Jordan" },
    { "id": 4, "name": "Jenna Maroney" }
  ]
}

First, you need to specify the selector path to the list. One it's own that will grab the list.

$ jq '.items' data.json
[
  {
    "id": 1,
    "name": "Liz Lemon"
  },
  ...
]

Then you need to use brackets to interact with the list. .items[0] and .items[1] would grab the first and second item in the list, respectively. Leaving the brackets empty (.items[]) tells jq that you want to interact with each item in the list.

Then tack on a selector for what you want out of each item.

$ jq '.items[].name' data.json
"Liz Lemon"
"Pete Hornberger"
"Tracy Jordan"
"Jenna Maroney"

This grabs the name from each of the objects within the items array. The results are printed to stdout.