title: Delete letters from string
body: <p>I have strings like '12454v', '346346z'. I want to delete all letters from strings.</p>
  
  <p>Re works fine:</p>
  
  <pre><code>import re
  str='12454v'
  re.sub('[^0-9]','', str)
  
  #return '12454'
  </code></pre>
  
  <p>Is there a way to do this without using regular expressions?</p>