In jq, how to convert nested arrays from an array of objects into a single object-CodePudding

I have a JSON document that looks like this

[
  {
    "id": "bbb",
    "lines": [
      "bla bla bla"
    ],
  },
  {
    "id": "ccc",
    "lines": [
      "lorem ipsum",
      "sample text"
    ]
  }
  {
    "id": "ddd",
    "lines": [
      "foo"
    ]
  },
  {
    "id": "eee",
    "lines": [
      "some text",
      "some more text",
      "foobar"
    ]
  }
]

I am attempting to use jq to modify this document into something that looks like this:

{
  "bbb_0": "bla bla bla",
  "ccc_0": "lorem ipsum",
  "ccc_1": "sample text",
  "ddd_0": "foo",
  "eee_0": "some text",
  "eee_1": "some more text",
  "eee_2": "foobar"
}

How would I achieve this? Thanks!

CodePudding user response：

You could use with_entries to convert the array into an object with defined keys, and reduce to construct the overall object:

jq '
  reduce .[] as {$id, $lines} ({};
    .   ($lines | with_entries(.key |= "\($id)_\(.)"))
  )
'

{
  "bbb_0": "bla bla bla",
  "ccc_0": "lorem ipsum",
  "ccc_1": "sample text",
  "ddd_0": "foo",
  "eee_0": "some text",
  "eee_1": "some more text",
  "eee_2": "foobar"
}

Demo

CodePudding user response：

Another way of achieving the desired output, using map, with_entries() and add:

map(.id as $id | .lines | with_entries(.key |= "\($id)_\(.)")) | add

Produces

{
  "bbb_0": "bla bla bla",
  "ccc_0": "lorem ipsum",
  "ccc_1": "sample text",
  "ddd_0": "foo",
  "eee_0": "some text",
  "eee_1": "some more text",
  "eee_2": "foobar"
}

Aa you can test in this online demo