Python新手有使用类的问题 [英] Python newbie having a problem using classes

问题描述

我只是开始搞乱了一些类;但是，我遇到了一个问题。

Im just beginning to mess around a bit with classes; however, I am running across a problem.

class MyClass(object):
    def f(self):
        return 'hello world'
print MyClass.f

< unbound method MyClass.f> 而不是预期值。如何解决此问题？

The previous script is returning <unbound method MyClass.f> instead of the intended value. How do I fix this?

推荐答案

MyClass.f 函数对象f，它是MyClass的一个属性。在你的情况下，f是一个实例方法（有一个自我参数），所以它在一个特定的实例上调用。它的未绑定，因为你指的是f而没有指定一个特定的类，有点像是指没有汽车的方向盘。

MyClass.f refers to the function object f which is a property of MyClass. In your case, f is an instance method (has a self parameter) so its called on a particular instance. Its "unbound" because you're referring to f without specifying a specific class, kind of like referring to a steering wheel without a car.

你可以创建一个实例MyClass，并从中调用f：

You can create an instance of MyClass and call f from it like so:

x = MyClass()
x.f()

（这指定从哪个实例调用f，所以可以参考实例变量等）

(This specifies which instance to call f from, so you can refer to instance variables and the like.)

您使用f作为静态方法。这些方法不绑定到一个特定的类，只能引用它们的参数。

You're using f as a static method. These methods aren't bound to a particular class, and can only reference their parameters.

一个静态方法将被创建并使用像这样：

A static method would be created and used like so:

class MyClass(object):
    def f():                 #no self parameter
        return 'hello world'
print MyClass.f()

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