title: Hive : How to convert string to array of arrays
body: <p>I have a hive column value stored as string</p>
  <pre><code>[[1,2],[3,4,8],[5,6,7,9]]
  </code></pre>
  <p>I need to find out the length of each inner array. How should i go about it ?</p>
  <p>Basically i need a query that sums up the sizes of each inner array. Had this column been stored as an array of arrays, i would do something like this</p>
  <pre><code>select sum(size(innerArray)) from myTab lateral view explode (mycol) arr as innerArray;
  </code></pre>
  <p>but now when i try the above, i get</p>
  <pre><code>FAILED: UDFArgumentException explode() takes an array or a map as a parameter
  </code></pre>