title: Python Pandas - How to compare the column values in a df with column values of another df
body: <p>I need to perform validation in two worksheets to see if the same value is filled in both the sheets.</p>
  <p>for example:
  in Sheet1, I have a column with Product and has value of WM001.
  in sheet2, I have a column with same name Product and has value of WM001 then its a Pass and I do nothing.</p>
  <p>In other case</p>
  <p>for example:
  in Sheet1, I have a column with Product and has value of WM001.
  in sheet2, I have a column with same name Product and has value of WM00X then its a Fail
  and I need to output the cell location and name so that we can go and correct the entry.</p>
  <p>I tried using merge outer join but in my case I need to compare the key itself. any suggestions.</p>
  <p>Do I need to loop both dataframes?</p>
  <p>Sheet1</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Product</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>WM001</td>
  </tr>
  <tr>
  <td>WM002</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Sheet2
  | Product  |
  | -------- |
  | WM001    |
  | WM00X    |</p>
  <p>The output should tell that the product WM00X is not found anywhere in Sheet1 and then putput the location and the value WM00X.</p>