title: Extract similar dates from multiple pandas data-frame
body: <p>My 500 data frames look like this, it is a <strong>day based</strong> data for 2 years.</p>
  
  <ol>
  <li>Date       |          Column A   |   Column B   </li>
  <li>2017-04-04  </li>
  <li>2017-04-05</li>
  <li>2017-04-06 </li>
  <li>2017-04-07 </li>
  <li>....</li>
  <li>2017-04-02   </li>
  <li>...</li>
  <li>2019-02-01 </li>
  <li>2019-02-11 </li>
  <li>2019-02-22 </li>
  <li>2019-02-27 </li>
  <li>2019-03-01 </li>
  <li>2019-04-01 </li>
  <li>2019-05-01 </li>
  </ol>
  
  <p>All the data frames have a similar number of columns, but a different number of rows. All these DataFrames have a few similar timestamps. I want to exact common timestamps from all my data frames.</p>
  
  <p>The goal is to filter out common timestamps in all my 500 data frames and create a subset of new 500 data frames with just common timestamps.</p>