Mastermind game in Python I am a C#/.Net developer and have decided it is time to branch out and really learn Python. I started with a simple implementation of a Mastermind-esque game. Any comments about the code would be greatly appreciated. I already know the gameplay isn't perfect, but it was just a quick attempt. I also am aware that there isn't much user input checking, but again, quick attempt.

import random

class Game(object):
    def run(self):
        guesses = []
        game_states = []
        length = int(input("Choose length of code to break: "))
        code = [random.randint(0, 9) for i in range(length)]

        def take_guess():
            correct_guess_length = False
            while not correct_guess_length:
                guess = input("Guess a number of length {0}: ".format(length))
                if len(guess) != length:
                    print("Guesses must be a number of length {0}.".format(length))
                else:
                    correct_guess_length = True
            return guess

        def check_guess(guess):
            return all([x == y for x, y in zip(guess, code)])

        def evaluate_guess(guess):
            new_state = []
            for pos, number in enumerate(guess):
                if code[pos] == number:
                    new_state.append(str(number))
                elif number in code:
                    new_state.append("O")
                else:
                    new_state.append("X")
            game_states.append(''.join([c for c in new_state]))

        def print_game_state():
            print()
            for guess, state in zip(guesses, game_states):
                print("{0}\t{1}".format(guess, state))

        correct = False
        while not correct:
            guess = take_guess()
            guesses.append(guess)
            guess_as_ints = [int(c) for c in guess]
            if not check_guess(guess_as_ints):
                evaluate_guess(guess_as_ints)
                print_game_state()
            else:
                print("You guessed the code was {0}! Congratulations!".format(''.join([str(i) for i in code])))
                correct = True

if __name__ == '__main__':
    game = Game()
    game.run()
Organization
As Simon points out, you shouldn't put the list of functions inside of run. It doesn't make much sense. Move them out into the class.
Use self
self in python is equivalent to this in C# and many other languages.
This:
    guesses = []
    game_states = []
    length = int(input(&quot;Choose length of code to break: &quot;))
    code = [random.randint(0, 9) for i in range(length)]

Should be this:
def __init__(self):
    self.guesses = []
    self.game_states = []
    self.code = [] # Add this later when you define length.

(Also, I would keep length as a local variable defined in run and then refer to len(self.code) instead.)
I would advise you look at how Python classes work.
You can replace random.randint(0, 9) with random.randrange(10).
Furthermore, once you pull the functions out of run, things like:
def take_guess():

become:
def take_guess(self):

Naming
        correct_guess_length = False

I expect a varaible with the name of length have some sort of integer (maybe real?) value. A boolean? Not often.
You don't really need this anyway!
            else:
                correct_guess_length = True

Can just be:
            else:
                break

I would probably just get rid of that too and say:
            else:
                return guess

Same thing goes for:
    correct = False
    while not correct:
        ...

You can get rid of these and use a break statement instead.
randrange
    code = [random.randint(0, 9) for i in range(length)]

Is pretty good except, randrange is a little more specialized for this:
    code = [random.randrange(10) for _ in range(length)]

(Also, when you disregard a variable the convention is to use _, not i.)
__str__
Since you rap everything in a game object, maybe you should give it a string representation overloading the __str__ function, and just print out the string representation of itself. Move print_game_state to __str__.