title: python re.sub replace number in match string
body: <p>Replacing numbers in a string after the match.</p>
  
  <pre><code>t = 'String_BA22_FR22_BC'
  re.sub(r'FR(\d{1,})','',t)
  </code></pre>
  
  <p>My desired output would be <code>String_BA22_FR_BC</code></p>