Updated to allow Python 3

boardHelpers.py

@@ -1,5 +1,8 @@
 from collections import defaultdict
-import StringIO
+try:
+    from StringIO import StringIO ## for Python 2
+except ImportError:
+    from io import StringIO ## for Python 3
 
 
 def isInBounds(board, colIdx, rowIdx):
@@ -96,7 +99,7 @@ def getInARowMetric(board, symbol, allowBlanks=False):
 def boardStr(board):
     numCols = len(board)
     numRows = len(board[0])
-    sio = StringIO.StringIO()
+    sio = StringIO()
     for rowIdx in reversed(range(numRows)):
         for colIdx in range(numCols):
             symbol = board[colIdx][rowIdx] or '-'

game.py

@@ -59,7 +59,7 @@ def takeTurn(self, verbose=False, pause=False):
         if verbose:
             print(self)
         if pause:
-            raw_input()
+            input()
 
 class MoveOutOfRange(Exception):
     pass

player.py

@@ -10,6 +10,11 @@
     boardStr
 )
 
+try:
+    BIG_NUM = sys.maxint # Python 2
+except AttributeError:
+    BIG_NUM = sys.maxsize # Python 3
+
 
 class Player(object):
     def nextMove(self, board):
@@ -20,7 +25,7 @@ def nextMove(self, board):
         moveChosen = False
         while not moveChosen:
             print(boardStr(board))
-            colIdx = raw_input('Which column?\n')
+            colIdx = input('Which column?\n')
             try:
                 colIdx = int(colIdx)
             except ValueError:
@@ -83,7 +88,7 @@ def miniMax(symbol, vsSymbol, board, heuristic, maxDepth, currentDepth):
     else:
         colIdxOptions = getAvailableColumns(board)
         bestOptions = []
-        bestValue = -sys.maxint
+        bestValue = -BIG_NUM
         for colIdx in colIdxOptions:
             newBoard = applyMoveToNewBoard(board, colIdx, symbol)
             newDepth = currentDepth + 1