title: Python - Compare 2 csv files and delete rows
body: <p>I have 2 csv files with ~10000 lines :</p>
  <ol>
  <li>csv of name files from directory</li>
  <li>csv with datas for each file in this directory (point 1)</li>
  </ol>
  <p>Example of content for each csv file :<br/>
  csv_1 :<br/></p>
  <pre><code>50001200000000016
  50001200000000021
  50001200000000034
  50001200000000048
  </code></pre>
  <p>csv_2:<br/></p>
  <pre><code>50001200000000016;187
  50001200000000021;287
  50001200000000034;187
  50001200000000048;5
  </code></pre>
  <p>I want to keep in csv_2 only the lines where the first column match and exist in csv_1</p>
  <p>Ex:<br/>
  If in csv_1 the line 50001200000000016 dont exist, delete the row in csv_2 who begins with 50001200000000016</p>
  <p>Thx for help</p>