title: Generate csv from nested json python
body: <p>I have following nested json file, which I need to convert in pandas dataframe, the main problem is there is only one unique item in the whole json and it is very deeply nested. </p>
  
  <p>I tried to solve this problem with the following code, but it gives repeating output.</p>
  
  <pre><code>[{
  "questions": [{
          "key": "years-age",
          "responseKey": null,
          "responseText": "27",
          "responseKeys": null
      },
      {
          "key": "gender",
          "responseKey": "male",
          "responseText": null,
          "responseKeys": null
      }
  
  ],
  "transactions": [{
          "accId": "v1BN3o9Qy9izz4Jdz0M6C44Oga0qjohkOV3EJ",
          "tId": "80o4V19Kd9SqqN80qDXZuoov4rDob8crDaE53",
          "catId": "21001000",
          "tType": "80o4V19Kd9SqqN80qDXZuoov4rDob8crDaE53",
          "name": "Online Transfer FROM CHECKING 1200454623",
          "category": [
              "Transfer",
              "Acc Transfer"
          ]
      }
  
  ],
  "institutions": [{
      "InstName": "Citizens company",
      "InstId": "inst_1",
      "accounts": [{
          "pAccId": "v1BN3o9Qy9izz4Jdz0M6C44Oga0qjohkOV3EJ",
          "pAccType": "depo",
          "pAccSubtype": "check",
          "_id": "5ad38837e806efaa90da4849"
      }]
  
  }]
  }]
  </code></pre>
  
  <p>I need to convert this to pandas dataframe as follows:</p>
  
  <pre><code> id                        pAccId                                  tId      
  
   5ad38837e806efaa90da4849  v1BN3o9Qy9izz4Jdz0M6C44Oga0qjohkOV3EJ   80o4V19Kd9SqqN80qDXZuoov4rDob8crDaE53   
  </code></pre>
  
  <p>The main problem I am facing is with the "id" as it very deeply nested which is the only unique key for the json.</p>
  
  <p>here is my code:</p>
  
  <pre><code>  import pandas as pd
    import json
    with open('sub.json') as f:
         data = json.load(f)
  
    csv = ''
    for k in data:
         for t in k.get("institutions"):
             csv += k['institutions'][0]['accounts'][0]['_id']
             csv += "\t"
             csv += k['institutions'][0]['accounts'][0]['pAccId']
             csv += "\t"
             csv += k['transactions'][]['tId']
             csv += "\t"
             csv += "\n"
  
  text_file = open("new_sub.csv", "w")
  text_file.write(csv)
  text_file.close()
  </code></pre>
  
  <p>Hope above code makes sense, as I am new to python.</p>