title: combining the information of several dataframes in boxplot
body: <p>I would like to generalize the problem raised by little in the post <a href="https://stackoverflow.com/questions/63087467/combining-the-information-of-two-dataframes-in-boxplot">combining the information of two dataframes in boxplot</a></p>
  <p>I have 20 files (my personnal running records), and I would like to display the evolution of my heart rate using boxplot.</p>
  <p>so my 20 df look like:</p>
  <pre><code>time_sec     Hears Rate
  0            74
  1            74
  2            75
  .            .
  N            145
  </code></pre>
  <p>and of course the duration of my activity is not exaltly the same</p>
  <p>the goal is to have 20 boxplot on the same figure.</p>
  <p>Any idea ?</p>