title: How merge or join data in a Pandas nested DataFrame
body: <p>I'm trying to figure out how to perform a Merge or Join on a nested field in a DataFrame. Below is some example data:</p>
  <pre class="lang-py prettyprint-override"><code>df_all_groups = pd.read_json(&quot;&quot;&quot;
  [
      {
          &quot;object&quot;: &quot;group&quot;,
          &quot;id&quot;: &quot;group-one&quot;,
          &quot;collections&quot;: [
              {
                  &quot;id&quot;: &quot;111-111-111&quot;,
                  &quot;readOnly&quot;: false
              },
              {
                  &quot;id&quot;: &quot;222-222-222&quot;,
                  &quot;readOnly&quot;: false
              }
          ]
      },
      {
          &quot;object&quot;: &quot;group&quot;,
          &quot;id&quot;: &quot;group-two&quot;,
          &quot;collections&quot;: [
              {
                  &quot;id&quot;: &quot;111-111-111&quot;,
                  &quot;readOnly&quot;: false
              },
              {
                  &quot;id&quot;: &quot;333-333-333&quot;,
                  &quot;readOnly&quot;: false
              }
          ]
      }
  ]
  &quot;&quot;&quot;)
  
  df_collections_with_names = pd.read_json(&quot;&quot;&quot;
  [
      {
          &quot;object&quot;: &quot;collection&quot;,
          &quot;id&quot;: &quot;111-111-111&quot;,
          &quot;externalId&quot;: null,
          &quot;name&quot;: &quot;Cats&quot;
        },
        {
          &quot;object&quot;: &quot;collection&quot;,
          &quot;id&quot;: &quot;222-222-222&quot;,
          &quot;externalId&quot;: null,
          &quot;name&quot;: &quot;Dogs&quot;
        },
        {
          &quot;object&quot;: &quot;collection&quot;,
          &quot;id&quot;: &quot;333-333-333&quot;,
          &quot;externalId&quot;: null,
          &quot;name&quot;: &quot;Fish&quot;
        }
  ]
  &quot;&quot;&quot;)
  </code></pre>
  <p>I'm trying to add the <code>name</code> field from <code>df_collections_with_names</code> to each <code>df_all_groups['collections'][&lt;index&gt;]</code> by joining on <code>df_all_groups['collections'][&lt;index&gt;].id</code> The output I'm trying to get to is:</p>
  <pre class="lang-py prettyprint-override"><code>[
      {
          &quot;object&quot;: &quot;group&quot;,
          &quot;id&quot;: &quot;group-one&quot;,
          &quot;collections&quot;: [
              {
                  &quot;id&quot;: &quot;111-111-111&quot;,
                  &quot;readOnly&quot;: false,
                  &quot;name&quot;: &quot;Cats&quot; // See Collection name was added
              },
              {
                  &quot;id&quot;: &quot;222-222-222&quot;,
                  &quot;readOnly&quot;: false,
                  &quot;name&quot;: &quot;Dogs&quot; // See Collection name was added
              }
          ]
      },
      {
          &quot;object&quot;: &quot;group&quot;,
          &quot;id&quot;: &quot;group-two&quot;,
          &quot;collections&quot;: [
              {
                  &quot;id&quot;: &quot;111-111-111&quot;,
                  &quot;readOnly&quot;: false,
                  &quot;name&quot;: &quot;Cats&quot; // See Collection name was added
              },
              {
                  &quot;id&quot;: &quot;333-333-333&quot;,
                  &quot;readOnly&quot;: false,
                  &quot;name&quot;: &quot;Fish&quot; // See Collection name was added
              }
          ]
      }
  ]
  </code></pre>
  <p>I've tried to use the <code>merge</code> method, but can't seem to get it to run on the <code>collections</code> nested field as I believe it's a series at that point.</p>