title: split string update numbers only
body: <p>I have a function using raw_input getting a sentence from user.  Then my second function splits the sentence so I am only trying to update the numbers on the sentence.  This is the split sentence:</p>
  
  <pre><code>['You', 'are', '42', 'this',  'year']
  </code></pre>
  
  <p>I am trying to update 42 to 43 do a return and print 'You are 43 this year'</p>
  
  <p>I am able to pull the number by using isdigit() but I can't increase it. This is what I have so far:</p>
  
  <pre><code>def GetDigits(sentence):
      for i in sentence:
          if i.isindigit():
             i = i +1
      return sentence
  </code></pre>