text: # The 6.00 Word Game
  
  import random
  import string
  
  VOWELS = 'aeiou'
  CONSONANTS = 'bcdfghjklmnpqrstvwxyz'
  HAND_SIZE = 4
  
  SCRABBLE_LETTER_VALUES = {
      'a': 1, 'b': 3, 'c': 3, 'd': 2, 'e': 1, 'f': 4, 'g': 2, 'h': 4, 'i': 1, 'j': 8, 'k': 5, 'l': 1, 'm': 3, 'n': 1, 'o': 1, 'p': 3, 'q': 10, 'r': 1, 's': 1, 't': 1, 'u': 1, 'v': 4, 'w': 4, 'x': 8, 'y': 4, 'z': 10
  }
  
  # -----------------------------------
  # Helper code
  # (you don't need to understand this helper code)
  
  WORDLIST_FILENAME = "words.txt"
  
  def loadWords():
      """
      Returns a list of valid words. Words are strings of lowercase letters.
      
      Depending on the size of the word list, this function may
      take a while to finish.
      """
      print("Loading word list from file...")
      # inFile: file
      inFile = open(WORDLIST_FILENAME, 'r')
      # wordList: list of strings
      wordList = []
      for line in inFile:
          wordList.append(line.strip().lower())
      print("  ", len(wordList), "words loaded.")
      return wordList
  
  def getFrequencyDict(sequence):
      """
      Returns a dictionary where the keys are elements of the sequence
      and the values are integer counts, for the number of times that
      an element is repeated in the sequence.
  
      sequence: string or list
      return: dictionary
      """
      # freqs: dictionary (element_type -> int)
      freq = {}
      for x in sequence:
          freq[x] = freq.get(x,0) + 1
      return freq
  	
  
  # (end of helper code)
  # -----------------------------------
  
  #
  # Problem #1: Scoring a word
  #
  def getWordScore(word, n):
      """
      Returns the score for a word. Assumes the word is a valid word.
  
      The score for a word is the sum of the points for letters in the
      word, multiplied by the length of the word, PLUS 50 points if all n
      letters are used on the first turn.
  
      Letters are scored as in Scrabble; A is worth 1, B is worth 3, C is
      worth 3, D is worth 2, E is worth 1, and so on (see SCRABBLE_LETTER_VALUES)
  
      word: string (lowercase letters)
      n: integer (HAND_SIZE; i.e., hand size required for additional points)
      returns: int >= 0
      """
      word = word.lower()
      word_score = 0
      for c in word:
          word_score += SCRABBLE_LETTER_VALUES[c]
      word_score *= len(word)
      if len(word) == n:
          word_score += 50
      
      return word_score
  
  
  #
  # Problem #2: Make sure you understand how this function works and what it does!
  #
  def displayHand(hand):
      """
      Displays the letters currently in the hand.
  
      For example:
      >>> displayHand({'a':1, 'x':2, 'l':3, 'e':1})
      Should print out something like:
         a x x l l l e
      The order of the letters is unimportant.
  
      hand: dictionary (string -> int)
      """
      for letter in hand.keys():
          for j in range(hand[letter]):
               print(letter,end=" ")       # print all on the same line
      print()                             # print an empty line
  
  #
  # Problem #2: Make sure you understand how this function works and what it does!
  #
  def dealHand(n):
      """
      Returns a random hand containing n lowercase letters.
      At least n/3 the letters in the hand should be VOWELS.
  
      Hands are represented as dictionaries. The keys are
      letters and the values are the number of times the
      particular letter is repeated in that hand.
  
      n: int >= 0
      returns: dictionary (string -> int)
      """
      hand={}
      numVowels = n // 3
      
      for i in range(numVowels):
          x = VOWELS[random.randrange(0,len(VOWELS))]
          hand[x] = hand.get(x, 0) + 1
          
      for i in range(numVowels, n):    
          x = CONSONANTS[random.randrange(0,len(CONSONANTS))]
          hand[x] = hand.get(x, 0) + 1
          
      return hand
  
  #
  # Problem #2: Update a hand by removing letters
  #
  def updateHand(hand, word):
      """
      Assumes that 'hand' has all the letters in word.
      In other words, this assumes that however many times
      a letter appears in 'word', 'hand' has at least as
      many of that letter in it. 
  
      Updates the hand: uses up the letters in the given word
      and returns the new hand, without those letters in it.
  
      Has no side effects: does not modify hand.
  
      word: string
      hand: dictionary (string -> int)    
      returns: dictionary (string -> int)
      """
      word = word.lower()
      new_hand = dict(hand)   # Create a *COPY* of the original hand.
      for c in word:
          new_hand[c] -= 1    # Decrement count for letter in copy of dictionary.
      
      return new_hand
  
  
  #
  # Problem #3: Test word validity
  #
  def isValidWord(word, hand, wordList):
      """
      Returns True if word is in the wordList and is entirely
      composed of letters in the hand. Otherwise, returns False.
  
      Does not mutate hand or wordList.
     
      word: string
      hand: dictionary (string -> int)
      wordList: list of lowercase strings
      """
      word = word.lower()
      assert not (len(word) == 0), "isValidWord: 'word' cannot be 0 length!"
      
      # Check that word is in wordList
      if not word in wordList:
          return False
      
      # Check that word is made up of letters in hand, including sufficient count
      word_freq_dict = getFrequencyDict(word)
      for k, v in word_freq_dict.items():
          if hand.get(k, 0) < v:
              return False
      
      return True
  
  
  #
  # Problem #4: Playing a hand
  #
  
  def calculateHandlen(hand):
      """ 
      Returns the length (number of letters) in the current hand.
      
      hand: dictionary (string-> int)
      returns: integer
      """
      hand_length = 0
      for k, v in hand.items():
          hand_length += v
          
      return hand_length
  
  
  def playHand(hand, wordList, n):
      """
      Allows the user to play the given hand, as follows:
  
      * The hand is displayed.
      * The user may input a word or a single period (the string ".") 
        to indicate they're done playing
      * Invalid words are rejected, and a message is displayed asking
        the user to choose another word until they enter a valid word or "."
      * When a valid word is entered, it uses up letters from the hand.
      * After every valid word: the score for that word is displayed,
        the remaining letters in the hand are displayed, and the user
        is asked to input another word.
      * The sum of the word scores is displayed when the hand finishes.
      * The hand finishes when there are no more unused letters or the user
        inputs a "."
  
        hand: dictionary (string -> int)
        wordList: list of lowercase strings
        n: integer (HAND_SIZE; i.e., hand size required for additional points)
        
      """
      # Keep track of the total score
      total_score = 0
      
      # As long as there are still letters left in the hand:
      while calculateHandlen(hand):
          # Display the hand
          print("Current Hand:", end="  ")
          displayHand(hand)
          # Ask user for input
          user_word = input('Enter word, or a "." to indicate that you are finished: ')
          # If the input is a single period:
          if user_word == ".":
              # End the game (break out of the loop)
              break
              
          # Otherwise (the input is not a single period):
          else:
              # If the word is not valid:
              if not isValidWord(user_word, hand, wordList):
                  # Reject invalid word (print a message followed by a blank line)
                  print("Invalid word, please try again.\n")
  
              # Otherwise (the word is valid):
              else:
                  # Tell the user how many points the word earned, and the updated total score, in one line followed by a blank line
                  word_score = getWordScore(user_word, n)
                  total_score += word_score
                  print('"{0}" earned {1}. Total: {2} points\n'.format(user_word, str(word_score), str(total_score)))
                  
                  # Update the hand 
                  hand = updateHand(hand, user_word)
  
      # Game is over (user entered a '.' or ran out of letters), so tell user the total score
      message = ""
      if not calculateHandlen(hand):
          message = "Run out of letters."
      else:
          message = "Goodbye!"
      
      print("{0} Total score: {1}".format(message, str(total_score)))
  
  #
  # Problem #5: Playing a game
  # 
  
  def playGame(wordList):
      """
      Allow the user to play an arbitrary number of hands.
  
      1) Asks the user to input 'n' or 'r' or 'e'.
        * If the user inputs 'n', let the user play a new (random) hand.
        * If the user inputs 'r', let the user play the last hand again.
        * If the user inputs 'e', exit the game.
        * If the user inputs anything else, tell them their input was invalid.
   
      2) When done playing the hand, repeat from step 1    
      """
      hand = []
      
      while True:
          user_input = input("Enter n to deal a new hand, r to replay the last hand, or e to end game: ").lower()
          if user_input == "n":
              hand = dealHand(HAND_SIZE)
              playHand(hand, wordList, HAND_SIZE)
          elif user_input == "r":
              if hand:
                  playHand(hand, wordList, HAND_SIZE)
              else:
                  print("You have not played a hand yet. Please play a new hand first!")
                  continue
          elif user_input == "e":
              break
          else:
              print("Invalid command.")
  
  
  #
  # Build data structures used for entire session and play game
  #
  if __name__ == '__main__':
      wordList = loadWords()
      playGame(wordList)
  