title: Sum all columns with a wildcard name search using Python Pandas
body: <p>I have a dataframe in python pandas with several columns taken from a CSV file.</p>
  
  <p>For instance, data =:</p>
  
  <pre><code>Day P1S1 P1S2 P1S3 P2S1 P2S2 P2S3
  1   1    2    2    3    1    2
  2   2    2    3    5    4    2
  </code></pre>
  
  <p>And what I need is to get the sum of all columns which name starts with P1... something like P1* with a wildcard.</p>
  
  <p>Something like the following which gives an error:</p>
  
  <blockquote>
    <p>P1Sum = data["P1*"]</p>
  </blockquote>
  
  <p>Is there any why to do this with pandas?</p>