title: Power Query - Table.TranformColumns
body: <p>I'm trying to add leading zeros into a column in power query call JobCodes. I know I can do this by adding a new column using <code>Text.Start([JobCodes],5,"0")</code>, but I don't want to add a new column and go back to remove the column I don't need. I want to be able to do this in one step using <code>Table.TransformColumns</code> function. Is this possible?</p>
  
  <h2>Code:</h2>
  
  <pre><code>Table.TransformColumns(#"Changed Type", each Text.PadStart([JobCodes],5,"0"))
  </code></pre>
  
  <h2>Error:</h2>
  
  <blockquote>
    <p>Expression.Error: We cannot convert a value of type Function to type List.
    Details:
        Value=Function
        Type=Type</p>
  </blockquote>