mastermind.py

## Mastermind program
import random

# Create a random number of 4 digits between 1 and 6
masterNumber = [random.randint(1,6) for r in range(4)]

# User gets 20 guesses
guesscount=20
numposition=0

#Loop through until the 4 numbers are guessed or the 20 guesses are exhausted
while guesscount>0 and numposition<4:
    print "You have {} guesses left".format(guesscount)

    # Get input and validate that it's in the proper range
    guess = raw_input("Guess my 4 digit number (digits between 1 and 6): ")
    while len([x for x in guess if x not in ("1","2","3","4","5","6")]) > 0:
        guess = raw_input("Invalid guess. Try again: ")

    # Convert input to integers
    guess = [int(x) for x in guess]

    # Find out the number of matches regardless of position. Using a copy of the master number, figure
    # out the number of correct guesses by looping through while popping correct matches. If our master
    # number could never repeat numbers, this would be as simple as len(set(masterNumber) - set(guess))
    # or len([x for x in masterNumber if x in guess])

    right=[]
    numbercopy = masterNumber[:]
    for x in range(4):
        if guess[x] in numbercopy:
            right.append(numbercopy.pop(numbercopy.index(guess[x])))
    numright = len(right)

    # Now find out the number of matches at the right position. Simple list comprehension for this one
    numposition = len([x for x in range(4) if guess[x]==masterNumber[x]])

    # Print out the information and decrement the guess counter
    print "You have {} digits correct and {} in the right position.".format(numright,numposition)
    print
    guesscount -=1

if numposition==4:
  print "CORRECT! The number was",masterNumber
else:
  print "You ran out of guesses. The number was",masterNumber