Question

我开始用python编写代码，然后使用pyzero制作一个简单的游戏。游戏结束后，我想删除某些类型类的所有现有实例，以允许游戏重新开始。我有该类所有实例的列表，但是使用remove（self）似乎会导致我无法解决的逻辑问题。

class Ball(Actor):
    ball_list = []

    def __init__(self, actor):               
        Actor.initiate_actor(self,"ball")
        Ball.ball_list.append(self)
        self.alive = True

    def kill(self):
        if self.alive:
            self.alive = False
            Ball.ball_list.remove(self) 


def new_game():
    global game_over, score

    for actor in Ball.ball_list:
        actor.kill()

    score = 0
    game_over = False


def draw():
    global game_over
    if game_over:
        screen.clear()
        screen.draw.text("Game Over", center = (WIDTH/2, HEIGHT/2), color = 'white')

    else:
        screen.clear()
        backdrop.draw()  
        for actor in Ball.ball_list:
            if actor.alive:
                actor.draw()

Answer 1

实际上，您在迭代列表时会从列表中删除对象。阅读How to remove items from a list while iterating?，以获取有关此主题的更多信息。

在从原始列表中删除项目时，创建列表的浅表副本（using System; using System.IO; using IWshRuntimeLibrary; using File = System.IO.File; public static class Shortcut { public static void CreateShortcut(string originalFilePathAndName, string destinationSavePath) { string fileName = Path.GetFileNameWithoutExtension(originalFilePathAndName); string originalFilePath = Path.GetDirectoryName(originalFilePathAndName); string link = destinationSavePath + Path.DirectorySeparatorChar + fileName + ".lnk"; var shell = new WshShell(); var shortcut = shell.CreateShortcut(link) as IWshShortcut; if (shortcut != null) { shortcut.TargetPath = originalFilePathAndName; shortcut.WorkingDirectory = originalFilePath; shortcut.Save(); } } public static void CreateStartupShortcut() { CreateShortcut(System.Reflection.Assembly.GetEntryAssembly()?.Location, Environment.GetFolderPath(Environment.SpecialFolder.Startup)); } public static void DeleteShortcut(string originalFilePathAndName, string destinationSavePath) { string fileName = Path.GetFileNameWithoutExtension(originalFilePathAndName); string originalFilePath = Path.GetDirectoryName(originalFilePathAndName); string link = destinationSavePath + Path.DirectorySeparatorChar + fileName + ".lnk"; if (File.Exists(link)) File.Delete(link); } public static void DeleteStartupShortcut() { DeleteShortcut(System.Reflection.Assembly.GetEntryAssembly()?.Location, Environment.GetFolderPath(Environment.SpecialFolder.Startup)); } }，请参见More on Lists）并遍历列表的副本：

Ball.ball_list[:]

无论如何，由于您要从列表中删除所有元素，因此只需调用def new_game(): global game_over, score for actor in Ball.ball_list[:]: actor.kill() score = 0 game_over = False

clear()

或删除所有元素（请参见del）

Ball.ball_list.clear()

分别创建一个新的空列表

del Ball.ball_list[:]

请注意，garbage collection释放了未使用的对象的内存，因此从（所有）列表中删除一个对象就足够了。此外，不必重置将被破坏的对象的属性。

无法删除类的实例

1 个答案: