title: Manipulating strings using slicing in python to add or delete a character
body: <p>I'm trying to create a hangman game in python, and one particular function is giving me trouble. I want to print the set of all available characters that the user has left to choose from. So I start out with available = 'abcdefghijklmnopqrstuvwxyz', and if my secretWord is 'apple' and the user guesses 'a' on the first try, then the new available set of characters for the next round it available = 'bcdefghijklmnopqrstuvwxyz'. I've tried putting together something as seen below but it doesn't work, some characters do get eliminated but if i type in 'z' for example, it's still remains in the string available.</p>
  
  <pre><code>if letter in lettersGuessed: 
                  print('Oops! you\'ve already guessed that letter, try again: ')
  elif letter in secretWord: #this is the part giving me trouble
                  c = available.find(letter)
                  available = available[0:c] + available[c+1:]
  </code></pre>
  
  <p>Also, if there is any other function or method that would make this easier to do besides string slicing, I would also appreciate in knowing that.</p>