title: How to extract only one capture group using regex for pandas dataframe?
body: <p>Python beginner here. I am struggling to use regex for pandas. I have a rows like this that need to split up into a column containing only the number.</p>
  
  <pre><code>rando45m text78 here 123  $    1   0% text here  5 . 6&amp;
  </code></pre>
  
  <p>I need it to be displayed as </p>
  
  <pre><code>     0    1    2   3 
  0   123   1    0   5
  </code></pre>
  
  <p>I have used the following 2 methods</p>
  
  <pre><code>df2 = df.Keep.str.extractall('(\d+)((\s+)|(\%))')
  
  df3 = df.Keep.str.extractall(r'(?&lt;=\s)(\d+)(?=\s+|\%)')
  </code></pre>
  
  <p>df2 includes the whitespace in the cell. df3 errors out for an assertion error. 
  Is there a way where I can only capture one group /1 for my dataframe?</p>
  
  <p>Thanks</p>