将游戏转换为面向对象的版本

Question

我编写了一个简单的控制台游戏，它允许我将我的玩家移动到一个有墙壁和空白区域的小关卡内。只需使用几个简单的函数即可完成所有操作。

我对 Python 比较陌生，但接下来我想学习 OOP，如果我想让这个游戏面向对象，我将如何继续？

我理解类和对象相当很好，但如果我不理解所有答案，请耐心等待。

这是当前的游戏：

LEVEL = [
    'xxxxxx',
    'x    x',
    'x i  x',
    'x    x',
    'x    x',
    'xxxxxx'
]


def get_block(x, y):
    """Gets a block at the given coordinates."""
    try:
        return LEVEL[y][x]
    except IndexError:
        return None


def set_block(x, y, block):
    """Sets a block at the given coordinates."""
    try:
        LEVEL[y] = LEVEL[y][:x] + block + LEVEL[y][x + 1:]
    except IndexError:
        pass


def get_player_position():
    """Gets player's position."""
    for y, row in enumerate(LEVEL):
        for x, column in enumerate(row):
            if column == 'i':
                return x, y


def set_player_position(x, y):
    """Sets player's position."""
    block = get_block(x, y)
    if block == ' ':
        px, py = get_player_position()
        set_block(px, py, ' ')
        set_block(x, y, 'i')


def main():
    """Entry point for the program."""
    cmd = ''
    while cmd.lower() not in ('quit', 'q'):
        print('\n' * 30)
        for row in LEVEL:
            print(row)
        cmd = input('Command: ').lower()
        px, py = get_player_position()
        if cmd == 'w':
            set_player_position(px, py - 1)
        elif cmd == 's':
            set_player_position(px, py + 1)
        elif cmd == 'a':
            set_player_position(px - 1, py)
        elif cmd == 'd':
            set_player_position(px + 1, py)
    print('Bye.')

if __name__ == '__main__':
    main()

Answer 1

您的问题非常开放，因此很难给出一个包罗万象的答案 - 所以我所做的是在您现有的代码中识别一个数据结构并将其变成一个类。

以前对全局数据结构进行操作的函数现在都是该类实例的所有公共方法，这是唯一允许在名为 _field 的私有属性中更改其中保存的数据的方法。

做这种事情是编写面向对象软件必不可少的第一步。

希望你觉得这个例子有点启发性。

class PlayingField(object):
    # Class constants
    PLAYER = 'i'
    EMPTY = ' '
    EDGE = 'x'
    DEFAULT_SIZE = 6

    def __init__(self, size=DEFAULT_SIZE):
        X, EMPTY = self.EDGE, self.EMPTY
        self._size = size
        # build playing field
        self._field = [size*X] + (size-2)*[X + (size-2)*EMPTY + X] + [size*X]
        self._set_block(2, 2, self.PLAYER)  # Initialize player's position.

    def display(self):
        print(30*'\n')
        for row in self._field:
            print(row)

    def get_player_position(self):
        """Gets player's position."""
        for y, row in enumerate(self._field):
            for x, column in enumerate(row):
                if column == self.PLAYER:
                    return x, y
        else:
            raise ValueError("Couldn't determine player's location on field")

    def set_player_position(self, x, y):
        """Sets player's position."""
        block = self._get_block(x, y)
        if block == self.EMPTY:
            px, py = self.get_player_position()
            self._set_block(px, py, self.EMPTY)
            self._set_block(x, y, self.PLAYER)


    # Private methods
    def _get_block(self, x, y):
        """Gets a block at the given coordinates."""
        try:
            return self._field[y][x]
        except IndexError:
            return None

    def _set_block(self, x, y, block):
        """Sets a block at the given coordinates."""
        try:
            self._field[y] = self._field[y][:x] + block + self._field[y][x + 1:]
        except IndexError:
            pass

def main():
    """Entry point for the program."""
    field = PlayingField()
    cmd = ''
    while cmd.lower() not in ('quit', 'q'):
        field.display()
        cmd = input('Command: ').lower()
        px, py = field.get_player_position()
        if cmd == 'w':
            field.set_player_position(px, py - 1)
        elif cmd == 's':
            field.set_player_position(px, py + 1)
        elif cmd == 'a':
            field.set_player_position(px - 1, py)
        elif cmd == 'd':
            field.set_player_position(px + 1, py)
    print('Bye.')

if __name__ == '__main__':
    main()