this is a project for udacity nanodegree stage 2 on programming https://classroom.udacity.com/nanodegrees/nd000/parts/0001345403/project

udacity stage 2 project final 8-22-2016

#this is the text acording to the difficulty level
easy =  '''
        Python is a widely used high-level, general purpose, interpreted, 
        dynamic programming language.Its design philosophy emphasizes code 
        readability... -https://en.wikipedia.org/wiki/Python_(programming_language)
        '''
medium ='''
        Python supports multiple programming paradigms, including 
        object-oriented, imperative and procedural 
        styles. It features a dynamic type system and automatic memory 
        management and has a large and comprehensive standard library. -https://en.wikipedia.org/wiki/Python_(programming_language)
        '''
hard =  '''
        Python interpreters are available for many operating systems, allowing 
        code to run on a wide variety of systems. Using third-party 
        tools, such as Py2exe or Pyinstaller , the code can be packaged 
        into stand-alone executable programs for some of the most popular 
        operating systems ... 
        -https://en.wikipedia.org/wiki/Python_(programming_language)
        '''
paragraphs = [easy, medium, hard] # We define the difficulty in a list

# This is the list of solutions
answers = [["Python", "general", "programming", "code"],  # for easy
              ["Python", "programming", "system", "large"],  # for medium
              ["Python", "Py2exe", "Pyinstaller", "systems"]]  # for hard

# ask users to chose a valid difficulty level.
def choose_level():
    level = raw_input("Enter a difficulty level: easy, medium or hard: ")

    if level == "easy":
        print "You selected Easy"
        return 0 #position on the list "paragraphs"
    elif level == "medium":
        print "You selected Medium"
        return 1
    elif level == "hard":
        print "You selected Hard"
        return 2
    else:
        print "Invalid selection"
        return choose_level()  # loop until they choose a valid option
#You could use for word in list_of_words: instead of using a while loop and declaring an index.
def process_paragraph(level, blank): # ask for the level, and blanks
    paragraph = paragraphs[level]
    # replace all the answers from current blank to the last one
    while blank < len(answers[level]):
        word_to_replace = answers[level][blank]
        list_of_words = paragraph.split(" ")
        index = 0
        # Replace the word_to_replace with ___number___
        for word in list_of_words:    
        #while index < len(list_of_words):
            if list_of_words[index] == word_to_replace:
                list_of_words[index] = "___" + str(blank + 1) + "___"
            index += 1
        blank += 1
        paragraph = " ".join(list_of_words)
    return paragraph

def play_game(level): #starts the game
    blank = 0
    # ask for the right answer until everything is filled.
    while blank < len(answers[level]):
        print process_paragraph(level, blank)
        question = "\nWhat should go in blank number " + str(blank + 1) + "?"
        answer = raw_input(question).lower()

        correct_answer = answers[level][blank].lower()
        if correct_answer == answer:
            print "Correct!"
            blank += 1
        else:
            print "Try again!"
    print paragraphs[level]
    print "\n I didnt think you where going to make it... but here you are!"
#
def main():
    print "Welcome to my matbils program"
    level = choose_level()
    if level < 3:
        play_game(level)

        #if level < 3:
        again = raw_input("Would you like to play againg?(Y/N)")
        if again == "Y":
            print "Yes! you win"
            main()
        else:
            exit()
    else:
        exit()
    print "you win"
    exit()

main()