title: Spark: How to convert a String to multiple columns
body: <p>I have a dataframe that contains a field item which is a string having a array of items:</p>
  <pre><code>[{&quot;item&quot;:&quot;76CJMX4Y&quot;},{&quot;item&quot;:&quot;7PWZVWCG&quot;},{&quot;item&quot;:&quot;967NBPMS&quot;},{&quot;item&quot;:&quot;72LC5SMF&quot;},{&quot;item&quot;:&quot;8N6DW3VD&quot;},{&quot;item&quot;:&quot;045QHTU4&quot;},{&quot;item&quot;:&quot;0UL4MMSI&quot;}]
  
  root
   |-- item: string (nullable = true)
  </code></pre>
  <p>I would like to get the item as array of string. Can someone let me know if there is a easy way to do this with default from_json ?</p>
  <p>root
  |-- item: array (nullable = true)</p>
  <p>So that I will only have</p>
  <pre><code>[&quot;76CJMX4Y&quot;, &quot;7PWZVWCG&quot;, &quot;967NBPMS&quot;, &quot;72LC5SMF&quot;, &quot;8N6DW3VD&quot;, &quot;045QHTU4&quot;, &quot;0UL4MMSI&quot;]
  </code></pre>
  <p>Thanks</p>