title: How to find value of one column in Dataframe in another Dataframe
body: <p>I have two dataframes namely:</p>
  
  <p>df1:</p>
  
  <pre><code>col1     col2
  A1         20
  B1         22         
  A2         23
  B2         24
  </code></pre>
  
  <p>df2:</p>
  
  <pre><code>Column1     Column2
  A1          20
  A2          23
  A3          25 
  A4          28
  B1          22
  B2          24
  B3          27
  B4          33
  </code></pre>
  
  <p>Now, I want to return all rows from df2 having values of df1</p>
  
  <p>Hence , output should be:</p>
  
  <p>df2:</p>
  
  <pre><code>A1         20
  B1         22         
  A2         23
  B2         24
  </code></pre>