Need help to parse and print only 'category' values either using jq or jsawk or shell script

Question

Need help to parse and print only category values either using jq or jsawk or shell script.

{
  "fine_grained": {
    "dog": [
      {
        "category": "cocker spaniel",
        "mark": 0.9958831668
      }
    ]
  },
  "coarse": [
    {
      "category": "dog",
      "mark": 0.948208034
    }
  ]
}

Sorry, but we have no idea what you're asking for. Please provide a sample input, its expected output and your best attempt at solving the problem so far. — , Dec 23 '15 at 00:16

score 1 · Answer 1 · answered Dec 23 '15 at 00:57

1

Assuming all category values are simple strings and you want all category values, regardless of where it is in the JSON, you could use this filter using jq:

.. | objects.category // empty

This returns the following strings:

"cocker spaniel"
"dog"

answered Dec 23 '15 at 00:57

Jeff Mercado

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'.. | objects.category ' did not work. it says objects.category command not found – Joseph Jan 04 '16 at 17:59
You're using `jq` right? That's not a command, it's a filter you pass in to `jq`. – Jeff Mercado Jan 04 '16 at 18:12

jq170727 · Answer 2 · 2017-09-21T05:12:03.277

Here is a solution which uses leaf_paths and select to find all the paths with a leaf "category" member and then extract the corresponding values with foreach

foreach (leaf_paths | select(.[-1] == "category")) as $p (
    .
  ; .
  ; getpath($p)
)

If your input is in a file called input.json and the above filter is in a file called filter.jq then the shell command

jq -f filter.jq input.json

should produce

"cocker spaniel"
"dog"

You can use the -r flag if you don't want the quotes in the output.

EDIT: I now realize a filter of the form foreach E as $X (.; .; R) can almost always be rewritten as E as $X | R so the above is really just

  (leaf_paths | select(.[-1] == "category")) as $p
| getpath($p)

Need help to parse and print only 'category' values either using jq or jsawk or shell script

2 Answers2