title: How to convert python JSON list to dataframe columns without looping
body: <p>I'm using python and trying to figure out how to do the following without using a loop.</p>
  <p>I have a dataframe that has several columns including one that has a JSON objects list.
  What I'm trying to do is convert the JSON string column into their own columns within the dataframe.
  For example I have the following dataframe:</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>name</th>
  <th>age</th>
  <th>group</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>John</td>
  <td>35</td>
  <td>[{&quot;testid&quot;: &quot;001&quot;, &quot;marks&quot;: 67}, {&quot;testid&quot;: &quot;002&quot;, &quot;marks&quot;: 70}]</td>
  </tr>
  <tr>
  <td>Ann</td>
  <td>20</td>
  <td>[{&quot;testid&quot;: &quot;001&quot;, &quot;marks&quot;: 75}, {&quot;testid&quot;: &quot;002&quot;, &quot;marks&quot;: 80}, {&quot;testid&quot;: &quot;003&quot;, &quot;marks&quot;: 87}]</td>
  </tr>
  <tr>
  <td>Emma</td>
  <td>25</td>
  <td>[{&quot;testid&quot;: &quot;001&quot;, &quot;marks&quot;: 90}, {&quot;testid&quot;: &quot;002&quot;, &quot;marks&quot;: 99}]</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I want to get marks for testid = 001 and testid = 002 as follows.</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>name</th>
  <th>age</th>
  <th>test_id1</th>
  <th>test_id2</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>John</td>
  <td>35</td>
  <td>67</td>
  <td>70</td>
  </tr>
  <tr>
  <td>Ann</td>
  <td>20</td>
  <td>75</td>
  <td>80</td>
  </tr>
  <tr>
  <td>Emma</td>
  <td>25</td>
  <td>90</td>
  <td>99</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Here is my dataset</p>
  
  <pre class="lang-js prettyprint-override"><code>[
     {
        &quot;name&quot;:&quot;John&quot;,
        &quot;age&quot;:35,
        &quot;group&quot;:[
           {
              &quot;testid&quot;:&quot;001&quot;,
              &quot;marks&quot;:67
           },
           {
              &quot;testid&quot;:&quot;002&quot;,
              &quot;marks&quot;:70
           }
        ]
     },
     {
        &quot;name&quot;:&quot;Ann&quot;,
        &quot;age&quot;:20,
        &quot;group&quot;:[
           {
              &quot;testid&quot;:&quot;001&quot;,
              &quot;marks&quot;:75
           },
           {
              &quot;testid&quot;:&quot;002&quot;,
              &quot;marks&quot;:80
           },
           {
              &quot;testid&quot;:&quot;003&quot;,
              &quot;marks&quot;:87
           }
        ]
     },
     {
        &quot;name&quot;:&quot;Emma&quot;,
        &quot;age&quot;:25,
        &quot;group&quot;:[
           {
              &quot;testid&quot;:&quot;001&quot;,
              &quot;marks&quot;:90
           },
           {
              &quot;testid&quot;:&quot;002&quot;,
              &quot;marks&quot;:99
           }
        ]
     }
  ]
  </code></pre>
  <p>Any idea is highly appreciated.
  Thank you.</p>