How can I get a value of a specific json key only on a certain level?-CodePudding

I have a huge nested json file and I want to get the values of "text" but only on a certain level as there are many "text" keys deeper in the json file. The level I mean would be the "text:"Hi" after "event":"user".

The file looks like this:

    {
    "_id":{
       "$oid":"123"
    },
    "events":[
      {
         "event":"action",

         "metadata":{
            "model_id":"12"
         },

         "action_text":null,
         "hide_rule_turn":false
      },
      {
         "event":"user",
         "text":"Hi",
         "parse_data":{
            "intent":{
               "name":"greet",
               "confidence":{
                  "$numberDouble":"0.9601748585700989"
               }
            },
            "entities":[
               
            ],
            "text":"Hi",
            "metadata":{
               
            },
            "text_tokens":[
               [
                  {
                     "$numberInt":"0"
                  },
                  {
                     "$numberInt":"2"
                  }
               ]
            ],
            "selector":{
               "ideas":{
                  "response":{
                     "responses":[
                        {
                           "text":"yeah"
                        },
                        {
                           "text":"No"
                        },
                        {
                           "text":"Goo"
                        }
                     ]
                  },

First I uses this function to get the text data but of course if gave me all of them:

    def json_extract(obj, key):
        """Recursively fetch values from nested JSON."""
        arr = []

       def extract(obj, arr, key):
           """Recursively search for values of key in JSON tree."""
           if isinstance(obj, dict):
              for k, v in obj.items():
                  if isinstance(v, (dict, list)):
                      extract(v, arr, key)
                  elif k == key:
                      arr.append(v)
          elif isinstance(obj, list):
              for item in obj:
                  extract(item, arr, key)
          return arr

      values = extract(obj, arr, key)
     return values

I also tried to access only the second level through this text but it gave me a KeyNotFound Error:

    for i in data["events"][0]:
       print(i["text"])

Maybe because that key is not in every nested list? ... I really don't know what else I could do

CodePudding user response：

Since events is a list, you can write a list comprehension (if there are multiple items you need), or you can use the next function to get an element that you need from the iterator:

event = next(e for e in data.get('events', list()) if e.get('event')=='user')
print(event.get('text', ''))

Using get method gives you the safety that it won't throw an exception if the key doesn't exist in the dictionary

Edit: If you need this for all events:

all_events = [e for e in data.get('events', list()) if e.get('event')=='user']
for event in all_events:
    print(event.get('text', ''))

CodePudding user response：

Convert your JSON to a Python dictionary (e.g., json.load or json.loads depending on how you're accessing the JSON). Then just pass a reference to the dictionary to this:

def json_extract(jdata):
    assert isinstance(jdata, dict)
    arr = []

    def _extract(d, arr):
        if 'event' in d and (t := d.get('text')):
            arr.append(t)
        for k, v in d.items():
            if k not in {'event', 'text'}:
                if isinstance(v, list):
                    for e in v:
                        if isinstance(e, dict):
                            _extract(e, arr)
                elif isinstance(v, dict):
                    _extract(v, arr)
        return arr
    return _extract(jdata, arr)

This will return a list of all values associated with the key 'text' providing that key is found in a dictionary that also has an 'event' key