ps5.py

# Problem Set 5: 6.00 Word Game
# Name: vaboro
# Collaborators: none
# Time: n/a
#

import random
import string

VOWELS = 'aeiou'
CONSONANTS = 'bcdfghjklmnpqrstvwxyz'
HAND_SIZE = 10

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 load_words():
    """
    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', 0)
    # wordlist: list of strings
    wordlist = []
    for line in inFile:
        wordlist.append(line.strip().lower())#I see some string formatting used here...
    print "  ", len(wordlist), "words loaded."
    return wordlist

def get_frequency_dict(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 get_word_score(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, plus 50 points if all n letters are used on
    the first go.

    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.

    word: string (lowercase letters)
    returns: int >= 0
    """
    # TO DO ...
    # Since the function assumes the word is a valid word, it doesn't check the word for validity. All it is supposed to do is to score the word.
    # The number of letters in a word can be less or equal to the maximum number of letters in the hand n
    # The means of counting letters in the word is needed. Then then number of letters in the word is compared to n and if they are equal
    # additional 50 points are added to the score.
    # score is an integer since scores of letters are integers

    score = 0 #initialize the score

    for letter in word:
        score = score + SCRABBLE_LETTER_VALUES[letter]

    if len(word) == n:
        score = score + 50

    return score
#
# Make sure you understand how this function works and what it does!
#
def display_hand(hand):
    """
    Displays the letters currently in the hand.

    For example:
       display_hand({'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,              # print all on the same line
    print                              # print an empty line

#
# Make sure you understand how this function works and what it does!
#
def deal_hand(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={}
    num_vowels = n / 3

    for i in range(num_vowels):
        x = VOWELS[random.randrange(0,len(VOWELS))]
        hand[x] = hand.get(x, 0) + 1

    for i in range(num_vowels, 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 update_hand(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 mutate hand.

    word: string
    hand: dictionary (string -> int)
    returns: dictionary (string -> int)
    """
    # TO DO ...

    #Since it is assumed that 'hand' has all the letters in 'word' this check is performed somewhere else in the program.
    #At least I need to keep in mind that somewhere in the program when the user inputs words it has to be checked if
    #'hand' actually has the necessary letter to compose the inputed 'word'
    #Not to mutate 'hand' the function has to create a new 'hand' that it returns. This new hand is a dictionary.
    #I will call it updated_hand
    #I assume that neither 'hand' nor 'word' are empty

    updated_hand = {} #declare the updated hand

    #first, I need to copy all values from hand to updated_hand
    #since dictionaries are muntable assigment creates a new reference to the same object, so, I cannot assign hand{} to updated_hand{} like
    #this: updated_hand = hand. This will create a new reference to values in 'hand'

    #create a deep copy of the 'hand'

    for key in hand.keys():
        updated_hand[key] = hand[key]

    for letter in word:
        if letter in updated_hand.keys():
            updated_hand[letter] -= 1
##            if updated_hand[letter] == 0:
##                updated_hand.pop(letter)
    return updated_hand


#
# Problem #3: Test word validity
#
def is_valid_word(word, hand, word_list):
    """
    Returns True if word is in the word_list and is entirely
    composed of letters in the hand. Otherwise, returns False.
    Does not mutate hand or word_list.

    word: string
    hand: dictionary (string -> int)
    word_list: list of lowercase strings
    """
    # TO DO ...

    #First, check if 'word' is in 'word_list', if not then 'word' is not a valid word
    #Second, convert 'word' into 'hand' format with get_frequency_dict() function
    #Then make a deep copy of the 'hand' and compare keys in the two dictionaries
    #'dict_word' and 'dict_hand' reducting the corresponding values if keys match

    is_valid = False

    dict_word = {}

    dict_hand = {}

    if word in word_list:

        dict_word = get_frequency_dict(word)

    else:

        return is_valid

    for key in hand.keys():
        dict_hand[key] = hand[key]

    #for each key in dict_word

    for word_key in dict_word.keys():

        #check if dict_hand contains word_key

        if dict_hand.has_key(word_key):

            #and if dict_hand doesn't have enough letters for dict_word

            if dict_hand[word_key] - dict_word[word_key] < 0:

                #the word is not valid

                return is_valid

            else:

                #otherwide decrease values of corresponding keys in dict_hand and dict_word

                dict_hand[word_key] -= dict_word[word_key]
                dict_word[word_key] -= dict_word[word_key]

        else:

            return is_valid

    #this is a debug print statement

    #print 'Word:', word, 'Dict_word:', dict_word, 'Hand:', hand, 'Dict_hand:', dict_hand

    is_valid = True

    return is_valid

#
# Problem #4: Playing a hand
#
def play_hand(hand, word_list):
    """
    Allows the user to play the given hand, as follows:

    * The hand is displayed.

    * The user may input a word.

    * An invalid word is rejected, and a message is displayed asking
      the user to choose another word.

    * When a valid word is entered, it uses up letters from the hand.

    * After every valid word: the score for that word and the total
      score so far are 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.
      The user can also finish playing the hand by inputing a single
      period (the string '.') instead of a word.

    * The final score is displayed.

      hand: dictionary (string -> int)
      word_list: list of lowercase strings
    """
    # TO DO ...

    word = ''
    total_score = 0
    letters_left = HAND_SIZE

    while word <> '.':
        if letters_left == 0:
            return
        print 'Current Hand:',
        display_hand(hand)
        print 'Enter word, or (.) to indicate that you are finished:',
        word = raw_input().lower()
        if word == '.':
            print 'Total score:', total_score, 'points.',
            return
        elif not is_valid_word(word, hand, word_list):
                print 'Invalid word, please try again.'
        else:
            score = get_word_score(word, HAND_SIZE)
            total_score += score
            print word, 'earned', score, 'points. Total:', total_score, 'points'
            hand = update_hand(hand, word)
            letters_left -= len(word)

#
# Problem #5: Playing a game
# Make sure you understand how this code works!
#
def play_game(word_list):
    """
    Allow the user to play an arbitrary number of hands.

    * Asks the user to input 'n' or 'r' or 'e'.

    * If the user inputs 'n', let the user play a new (random) hand.
      When done playing the hand, ask the 'n' or 'e' question again.

    * 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, ask them again.
    """
    # TO DO ...
    #print "play_game not implemented."         # delete this once you've completed Problem #4
    #play_hand(deal_hand(HAND_SIZE), word_list) # delete this once you've completed Problem #4

    ## uncomment the following block of code once you've completed Problem #4
    hand = deal_hand(HAND_SIZE) # random init
    while True:
        cmd = raw_input('Enter n to deal a new hand, r to replay the last hand, or e to end game: ')
        if cmd == 'n':
            hand = deal_hand(HAND_SIZE)
            play_hand(hand.copy(), word_list)
            print
        elif cmd == 'r':
            play_hand(hand.copy(), word_list)
            print
        elif cmd == 'e':
            break
        else:
            print "Invalid command."

#
# Build data structures used for entire session and play game
#
if __name__ == '__main__':
    word_list = load_words()
    play_game(word_list)