我可以在不使用Python创建新类的情况下覆盖类函数吗? [英] Can I override a class function without creating a new class in Python?

问题描述

我正在pygame中制作游戏，我做了一个抽象"类，唯一的工作是将给定关卡的sprite存储(目的是将这些关卡对象存储在列表中，以方便玩家移动)从一个级别到另一个级别)

I'm making a game in pygame and I have made an 'abstract' class that's sole job is to store the sprites for a given level (with the intent of having these level objects in a list to facilitate the player being moved from one level to another)

好的，这个问题.如果我能在Python中做到这一点(Java的代码致谢):

Alright, so to the question. If I can do the equivalent of this in Python(code curtesy of Java):

Object object = new Object (){
    public void overriddenFunction(){
        //new functionality
        };
    };

比起我在游戏中构建关卡时，我只需要用有关精灵位置的信息覆盖构造函数(或负责构建关卡的类/实例方法)，因为为该类创建了一个新类.游戏中的每个关卡都不是一个完美的答案.或者，我将必须在关卡类中创建方法，然后在实例化关卡对象后将其构建，然后根据需要放置精灵.

Than when I build the levels in the game I would simply have to override the constructor (or a class/instance method that is responsible for building the level) with the information on where the sprites go, because making a new class for every level in the game isn't that elegant of an answer. Alternatively I would have to make methods within the level class that would then build the level once a level object is instantiated, placing the sprites as needed.

因此，在一位更坚强的开发人员继续研究这种反Python的方式之前(我已经读了很多本网站的内容，以便从Python专家那里获得共鸣)，只是告诉我它是否可行.

So, before one of the more stanch developers goes on about how anti-python this might be (I've read enough of this site to get that vibe from Python experts) just tell me if its doable.

推荐答案

是的，可以！

class Foo(object):
    def do_other(self):
        print 'other!'
    def do_foo(self):
        print 'foo!'


def do_baz():
    print 'baz!'

def do_bar(self):
    print 'bar!'

# Class-wide impact
Foo.do_foo = do_bar
f = Foo()
g = Foo()
# Instance-wide impact
g.do_other = do_baz

f.do_foo()
f.do_other()

g.do_foo()
g.do_other()

因此，在一位更坚强的开发人员继续探讨这可能是如何反Python之前

So, before one of the more stanch developers goes on about how anti-python this might be

以这种方式覆盖函数(如果您有充分的理由这么做)在我看来似乎很Python化.一个可能需要这样做的原因/方式的示例是，如果您拥有一个动态功能，而静态继承不适用或不适用.

Overwriting functions in this fashion (if you have a good reason to do so) seems reasonably pythonic to me. An example of one reason/way for which you might have to do this would be if you had a dynamic feature for which static inheritance didn't or couldn't apply.

反对的案例可能在Python的Zen中找到:

The case against might be found in the Zen of Python:

• 美丽胜于丑陋.
• 可读性计数.
• 如果难以解释实现方式，那是个坏主意.

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