tic tac toe

My son and his cousins have occasionally expressed an interest in programming (they are 2*13 + 15). But what they mean is, they want to make a game like, say, Halo. And when I explain that GUIs take a bit of doing, not to mention AI, they go back to reading Harry Potter or whatever.

I did play with Scratch. Check it out, it's fun. But I think it gets awkward after a while.

I thought, so OK, let's do a game with the command-line for IO. And I adapted my tic-tac-toe program to this goal. It is short and simple. Rather than read the code, however, I urge you to make your own version.

Here is the printout:

. . . 1 2 3 . . . 4 5 6 . . . 7 8 9 Please pick a valid move, or q(quit) or r(reset) -> 1 You picked move = 1 P . . 1 2 3 . . . 4 5 6 . . . 7 8 9 Computer picked move = 7 P . . 1 2 3 . . . 4 5 6 C . . 7 8 9 Please pick a valid move, or q(quit) or r(reset) -> 9 You picked move = 9 P . . 1 2 3 . . . 4 5 6 C . P 7 8 9 player has a winning move in [1, 5, 9] returning 4 Computer picked move = 5 P . . 1 2 3 . C . 4 5 6 C . P 7 8 9 Please pick a valid move, or q(quit) or r(reset) -> 3 You picked move = 3 P . P 1 2 3 . C . 4 5 6 C . P 7 8 9 player has a winning move in [1, 2, 3] returning 1 Computer picked move = 2 P C P 1 2 3 . C . 4 5 6 C . P 7 8 9 Please pick a valid move, or q(quit) or r(reset) -> 6 You picked move = 6 P C P 1 2 3 . C P 4 5 6 C . P 7 8 9 You won! :) Want to play again? Please pick a valid move, or q(quit) or r(reset) -> q

Since I grafted the new IO on top of the game logic, I think that it would benefit from a redesign but I haven't done that yet. Here is the code (128 lines, with blanks). For the future: make the logic cleaner. Also, recognize when a game must be drawn, and bail.

import sys, random, time rows = [ [0,1,2], [3,4,5], [6,7,8] ] cols = [ [0,3,6], [1,4,7], [2,5,8] ] diags = [ [0,4,8], [2,4,6] ] corners = [0,2,6,8] all = rows + cols + diags def printBoard(bL): print for i,e in enumerate(bL): if i and not i % 3: if i == 3: print ' 1 2 3' elif i == 6: print ' 4 5 6' if e: print e + ' ', else: print '. ', print ' 7 8 9' print def openCorners(bL): rL = list() for i in corners: if not bL[i]: rL.append(i) return rL #------------------------------------------ def askPlayer(bL): played = [i+1 for i,s in enumerate(bL) if s] nogood = played p = 'Please pick a valid move,\n' p += 'or q(quit) or r(reset) -> ' s = raw_input(p) while True: if not s or s == '\n': print '\nNo input' print 'Sorry that move is no good :(\n' s = raw_input(p) continue if s[0] in ['q','Q']: sys.exit() if s[0] in ['r']: runloop() try: i = int(s) except ValueError: print 'Sorry that move is no good :(\n' s = raw_input(p) continue if i in nogood: print 'Sorry that move is no good :(\n' s = raw_input(p) continue if not s in nogood: break print "You picked move = ", s return s #========================================== def testWinner(bL): # also draw if bL.count(None) == 0: print 'Draw' return 'N' for line in all: values = [bL[i] for i in line] if values.count('P') == 3: print 'You won! :)' return 'P' elif values.count('C') == 3: print 'I win. Sucks to be you :)' return 'C' return None def whoCanWin(bL,who='C'): rL = list() for line in all: vL = [bL[i] for i in line] if vL.count(None) == 1: if vL.count(who) == 2: rL.append(line) return rL #------------------------------------------ def pickComputerMove(bL): L = whoCanWin(bL,who='C') # computer if L: for i in random.choice(L): if not bL[i]: return i L = whoCanWin(bL,who='P') # player if L: print "Player has a winning move in", print [i+1 for i in L[0]] for i in L[0]: if not bL[i]: print "returning ",i return i if not bL[4] and random.random() < 0.8: return 4 # "usually" pick open center L = openCorners(bL) if L: return random.choice(L) return random.choice( [i for i,e in enumerate(bL) if not e]) def computersTurn(bL): time.sleep(0.5) # I'm thinking, OK? i = pickComputerMove(bL) print "Computer picked move = ", i+1 bL[i] = 'C' #------------------------------------------ def runloop(): bL = [None] * 9 printBoard(bL) while True: s = askPlayer(bL) bL[int(s)-1] = 'P' printBoard(bL) if testWinner(bL): break computersTurn(bL) if testWinner(bL): break printBoard(bL) print '\nWant to play again?' runloop() runloop()