在 Python 中在运行时为对象分配方法 [英] Assigning method to object at runtime in Python

问题描述

我正在尝试在 Python 中执行等效的 Javascript:

I'm trying to do the Javascript equivalent in Python:

a.new_func = function(arg1, arg2) {
    var diff = arg1 - arg2;
    return diff * diff;
}

现在，我这样做的方式是先定义方法，然后分配它，但我的问题是 Python 是否允许速记在同一行中进行分配和定义部分.像这样:

Right now, the way I'm doing this is by defining the method first, and then assigning it, but my question is whether or not Python allows a shorthand to do the assigning and the defining part in the same line. Something like this:

a.new_func = def new_func(arg1, arg2):
    diff = arg1 - arg2
    return diff * diff

取而代之的是:

def new_func(arg1, arg2):
    diff = arg1 - arg2
    return diff * diff
a.new_func = new_func

我意识到差异并不大，但我仍然很想知道这是否可能.

I realize the difference is not major, but am still interested to know whether or not it's possible.

推荐答案

Python 不支持这种语法.

Python supports no such syntax.

我想如果你愿意，你可以写一个装饰器.它可能看起来更好一点:

I suppose if you wanted, you could write a decorator. It might look a bit nicer:

def method_of(instance):
    def method_adder(function):
        setattr(instance, function.__name__, function)
        return function
    return method_adder

@method_of(a)
def new_func(arg1, arg2):
    stuff()

或者如果您希望该方法可以访问self:

Or if you want the method to have access to self:

def method_of(instance):
    def method_adder(function):
        setattr(instance, function.__name__, function.__get__(instance))
        return function
    return method_adder

@method_of(a)
def new_func(self, arg1, arg2):
    stuff()

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