title: Counting vowels in a string using recursion
body: <p>I understand that recursion is when a function calls itself, however I can't figure out how exactly to get my function to call it self to get the desired results. I need to simply count the vowels in the string given to the function.</p>
  
  <pre><code>def recVowelCount(s):
      'return the number of vowels in s using a recursive computation'
      vowelcount = 0
      vowels = "aEiou".lower()
      if s[0] in vowels:
          vowelcount += 1
      else:
          ???
  </code></pre>
  
  <hr>
  
  <p>I came up with this in the end, thanks to some insight from here.</p>
  
  <pre><code>def recVowelCount(s):
  'return the number of vowels in s using a recursive computation'
  vowels = "aeiouAEIOU"
  if s == "":
      return 0
  elif s[0] in vowels:
      return 1 + recVowelCount(s[1:])
  else:
      return 0 + recVowelCount(s[1:])
  </code></pre>