title: Convert array(double) to varchar in Presto
body: <p>I'm trying to convert Array(double) to varchar in Presto.
  A sample value:
  [99.0,98.0,99.0,95.0,99.0,88.0,90.0,79.0,90.0,56.0,90.0,90.0,92.0,90.0,93.0,99.0]</p>
  <p>I tried the cast function below:</p>
  <p><code>cast(colname as varchar)</code></p>
  <p>But got this error message: <em>&quot;Cannot cast array(double) to varchar&quot;</em></p>
  <p>Any ideas how to convert this array to varchar.
  Thanks</p>