title: Removing everything except letters and spaces from string in Python3.3
body: <p>I have this example string: <code>happy t00 go 129.129</code> and I want to keep only the spaces and letters. All I have been able to come up with so far that is pretty efficient is:</p>
  
  <pre><code>print(re.sub("\d", "", 'happy t00 go 129.129'.replace('.', '')))
  </code></pre>
  
  <p>but it is only specific to my example string. How can remove all characters other than letters and spaces? </p>