SnakeGame | Python Fiddle

def snakeGame(gameBoard, commands):
    def setGB(x, y, c):
        gameBoard[x][y] = c
    def valid(x, y):
        return x in range(len(gameBoard)) and y in range(len(gameBoard[0]))
    moves = {'<': lambda x, y: (x, y-1),
             '>': lambda x, y: (x, y+1),
             '^': lambda x, y: (x-1, y),
             'v': lambda x, y: (x+1, y)}
    rotations = {'<': {'L': 'v', 'R': '^'},
                 '>': {'L': '^', 'R': 'v'},
                 '^': {'L': '<', 'R': '>'},
                 'v': {'L': '>', 'R': '<'}}
    snake = {}
    for (i, row) in enumerate(gameBoard):
        for (j, c) in enumerate(row):
            if c == '.': continue
            if c in {'<', '>', '^', 'v'}:
                headPos = (i, j)
                headDir = c
            snake[(i, j)] = []
            if (i-1, j) in snake.keys():
                snake[(i, j)].append((i-1, j))
                snake[(i-1, j)].append((i, j))
            if (i, j-1) in snake.keys():
                snake[(i, j)].append((i, j-1))
                snake[(i, j-1)].append((i, j))
    tailPos = next(filter(lambda x: len(snake[x]) == 1 and x != headPos, snake.keys())) if len(snake) > 1 else headPos
    for cmd in commands:
        if cmd == 'F':
            newHeadPos = moves[headDir](*headPos)
            if valid(*newHeadPos) and (not newHeadPos in snake.keys()):
                snake[newHeadPos] = []
                setGB(*newHeadPos, headDir)
                if len(snake) == 1:
                    setGB(*headPos, '.')
                    del snake[headPos]
                else:
                    setGB(*tailPos, '.')
                    newTailPos = snake[tailPos][0]
                    snake[newTailPos].remove(tailPos)
                    del snake[tailPos]
                    tailPos = newTailPos
                    setGB(*headPos, '*')
                    snake[headPos].append(newHeadPos)
                    snake[newHeadPos].append(headPos)
                headPos = newHeadPos
            else:
                for pos in snake.keys():
                    setGB(*pos, 'X')
                break
        else:
            headDir = rotations[headDir][cmd]
    print('%s', gameBoard)
    return gameBoard

gameBoard([['.', '.', '.', '.'],
           ['.', '*', '>', '.'],
           ['.', '.', '.', '.']], 'F')

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