title: Get the columns where value is changing timeseriesly
body: <p>My dataframe has more than 200 columns. Sample Dataframe looks like</p>
  <pre><code>Date        Tkr col1    col2    col3
  20210101    APD 20.0    19.0    15.0
  20210101    BCD 20.0    19.0    15.0
  20210102    APD 19.0    19.0    15.0
  20210102    BCD 20.1    19.2    15.0
  </code></pre>
  <p>I'm trying to extract the columns from <code>col1</code>, <code>col2</code>, <code>col3</code>, where values of these columns are changing <code>daily</code> for any <code>Tkr</code>. For example <code>col3</code> is not changing, for any <code>Tkr</code> on any <code>Date</code>, but the value of <code>col1</code> is changing for every <code>Tkr</code> &amp; <code>col2</code> is changing for any one <code>Tkr</code>, so i'm trying to get <code>col1</code> and <code>col2</code>.</p>
  <p>I'm thinking to implement it with groupBy 'Date' &amp; <code>Tkr</code>, but after that, i need help to do this.</p>