title: To extract distinct values for all categorical columns in dataframe
body: <p>I have a situation where I need to print all the distinct values that are there for all the categorical columns in my data frame
  The dataframe looks like this :</p>
  
  <pre><code>Gender  Function  Segment
  M       IT        LE
  F       IT        LM
  M       HR        LE
  F       HR        LM
  </code></pre>
  
  <p>The output should give me the following:</p>
  
  <pre><code>Variable_Name    Distinct_Count
  Gender           2
  Function         2
  Segment          2
  </code></pre>
  
  <p>How to achieve this?</p>