Using the following code I was able to map a list of dictionaries by a key

import json

values_list = [{"id" : 1, "user":"Rick", "title":"More JQ"}, {"id" : 2, "user":"Steve", "title":"Beyond"}, {"id" : 1, "user":"Rick", "title":"Winning"}]
result      = {}

for data in values_list:
  id    = data['id']
  user  = data['user']
  title = data['title']
  if id not in result:
    result[id] = {
    'id' : id,
    'user' : user,
    'books' : {'titles' : []}
    }
  result[id]['books']['titles'].append(title)

print(json.dumps((list(result.values())), indent=4))

Knowing how clean is Jolt Spec and trying to separate the schema outside of the code. Is there a way to use Jolt Spec to achieve the same result.

The Result

[
  {
    "id": 1,
    "user": "Rick",
    "books": {
      "titles": [
        "More JQ",
        "Winning"
      ]
    }
  },
  {
    "id": 2,
    "user": "Steve",
    "books": {
      "titles": [
        "Beyond"
      ]
    }
  }
]

CodePudding user response：

You can use three levels of consecutive specs

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "*": "@(1,id).&",
        "title": "@(1,id).books.&s[]"
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "*": ""
    }
  },
  {
    "operation": "cardinality",
    "spec": {
      "*": {
        "id": "ONE",
        "user": "ONE"
      }
    }
  }
]

• in the first spec, the common id values are combined by "@(1,id)." expression
• in the second spec, the integer keys(1,2) of the outermost objects are removed
• in the last spec,only the first of the repeating elements are picked