title: Check common rows between two dataframes and replace the matched rows of second dataframe, with the values of df1
body: <p>I have two data frames, Let's say df1 and df2. Both data frames have the same column named URL and Age. I want to check if df1['URL'] in df2['URL'], then replace the df2['Age'] with df1['Age'] for the matched row and keep the remaining rows in df2 without any change.</p>
  
  <p>df1</p>
  
  <pre><code>URL          Category                         Age     
  google.com  [IAB19, Technology &amp; Computing]   A
  youtube.com [IAB25, Non-Standard Content]     H
  facebook.co [IAB14, Society]                  A
  amazon.com  [IAB22, Shopping]                 M
  wpedia.org  [IAB5, Education]                 E
  </code></pre>
  
  <p>df2</p>
  
  <pre><code>URL          Category         Age     
  google.com  [IAB19, BBCA]     T
  youtube.com [IAB25, AACB]     T
  facebook.co [IAB14, HLGB      T 
  amazon.com  [IAB22, ETCL]     T
  wpedia.org  [IAB5, J TCL]     T
  example1.com [LHTB, 2213]     A
  example2.com [OPCL, 9909]     A
  example3.com [PPRS, 7656]     A
  </code></pre>
  
  <p>Now, I want to check if any URL in the df1['URL'] exists in df2['URL'], I want to replace df2['Age'] with df1['Age'] and keeping the uncommon URLS without any change.</p>
  
  <p>So, the expected output will be:</p>
  
  <p>df3</p>
  
  <pre><code>URL          Category         Age     
  google.com  [IAB19, BBCA]     A
  youtube.com [IAB25, AACB]     H
  facebook.co [IAB14, HLGB      A
  amazon.com  [IAB22, ETCL]     M
  wpedia.org  [IAB5, J TCL]     E
  example1.com [LHTB, 2213]     A
  example2.com [OPCL, 9909]     A
  example3.com [PPRS, 7656]     A
  </code></pre>