title: Separate number from unit in a string in Python
body: <p>I have strings containing numbers with their units, e.g. 2GB, 17ft, etc.
  I would like to separate the number from the unit and create 2 different strings. Sometimes, there is a whitespace between them (e.g. 2 GB) and it's easy to do it using split(' ').</p>
  
  <p>When they are together (e.g. 2GB), I would test every character until I find a letter, instead of a number. </p>
  
  <pre><code>s='17GB'
  number=''
  unit=''
  for c in s:
      if c.isdigit():
          number+=c
      else:
          unit+=c
  </code></pre>
  
  <p>Is there a better way to do it?</p>
  
  <p>Thanks</p>