title: How to find a word that starts with a specific character
body: <p>I want to sort out words which are started with 's' in sentence by python.<br>
  Here is my code:</p>
  
  <pre><code>import re
  text = "I was searching my source to make a big desk yesterday."
  m = re.findall(r'[s]\w+', text)
  print m
  </code></pre>
  
  <p>But the result of code is : </p>
  
  <pre><code>['searching', 'source', 'sk', 'sterday'].
  </code></pre>
  
  <p>How do I write a code about regular expression? Or, is there any method to sort out words?</p>