title: Pandas Select last 20 days of data.
body: <p>I have a simple question I cant seem to find a strait answer for. </p>
  
  <p>Suppose I have a data frame with date, open, high, low, close and volume. </p>
  
  <p>What I am trying to do is first find the current date which I can do with:</p>
  
  <pre><code>today = pd.datetime.today().date()
  </code></pre>
  
  <p>My issue comes in selecting the last 20 days of data from the current date. </p>
  
  <p>I need to select the last 20 rows because I need to then find the highest and lowest values in the close colum of this dataset. </p>
  
  <p>Any pointers would help a lot. Iv searched google for a while and keep finding different answers. </p>
  
  <p>Thanks!</p>