title: Count vowels from raw input
body: <p>I have a homework question which asks to read a string through raw input and count how many vowels are in the string. This is what I have so far but I have encountered a problem:</p>
  
  <pre><code>def vowels():
      vowels = ["a","e","i","o","u"]
      count = 0
      string = raw_input ("Enter a string: ")
      for i in range(0, len(string)):
          if string[i] == vowels[i]:
              count = count+1
      print count
  
  vowels()
  </code></pre>
  
  <p>It counts the vowels fine, but due to <code>if string[i] == vowels[i]:</code>, it will only count one vowel once as <code>i</code> keeps increasing in the range. How can I change this code to check the inputted string for vowels without encountering this problem?</p>