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Code:
# Lab 9 - Markov Analysis

# CMPUT 174 W11



import random

import sys



def shift (prefix, word):

    """

    Pops a word out of a tuple and pushes another word in

    """

    return prefix[1:] + (word,)



def readWords(fin):

    """

    Reads the file into the words list

    """

    wordsList = []

    for line in fin:

        wordsList.extend(line.split(' '))

    return wordsList



def analyze(wordsList,suffixes):

    """

    Perform the Markov Analysis

    """

    possibleSuffixes = dict()

    # Your code goes here

    

    prefix = []

    prefix.append((wordsList[0],wordsList[1]))

    

    for i in range(len(wordsList)-2):

        if prefix[i] not in possibleSuffixes:

            possibleSuffixes[prefix[i]] = [wordsList[i+2]]

        else:

            possibleSuffixes[prefix[i]].append(wordsList[i+2])

        prefix.append((wordsList[i+1],wordsList[i+2]))

        

    print 'possible suffixes:',possibleSuffixes

    print 'prefixes', prefix



    return possibleSuffixes



def generate(suffixes, prefix):

    """

    Generate text based on the known suffixes

    """

    generatedText = prefix[0] + " " + prefix[1]

    prefix = prefix[0],prefix[1]

    print "First pair: ", prefix



    # Your code goes here

    i = 1

    suffix = prefix[1]

    print suffix

    while i != 0:

        if  suffix not in prefix[i]:

            i = 1

            exit()

        else:

            suffix = suffixes.get(prefix)

            if len(suffix) > 1:

                suffix = [random.choice(suffix)]

                print "Random choosen:",suffix

            prefix = shift(prefix,suffix[0])

            print "Prefixes after:",prefix

            print "Suffix:", suffix

            i += 1

            

            generatedText = generatedText + " " + suffix[0]

    return generatedText



if __name__ == "__main__":

    # The input file as a list of words in order

    #filename = sys.argv[1]

    filename = "Input.txt"

    fin = open(filename)

    words = readWords(fin);

    

    suffixes = dict()



    # Do the analysis and return the dictionary that maps every tupple into a prefix word

    suffixes = analyze(words, suffixes)

    

    # Pick a starting prefix at random

    startingPrefix = random.choice(suffixes.keys())



    # Generate the text and print it

    print generate(suffixes, startingPrefix)
Markov Analysis