我建议大家应该读读Guido van Rossum关于这个话题的博客——为什么外显的自我必须留下来。

When a method definition is decorated, we don't know whether to automatically give it a 'self' parameter or not: the decorator could turn the function into a static method (which has no 'self'), or a class method (which has a funny kind of self that refers to a class instead of an instance), or it could do something completely different (it's trivial to write a decorator that implements '@classmethod' or '@staticmethod' in pure Python). There's no way without knowing what the decorator does whether to endow the method being defined with an implicit 'self' argument or not. I reject hacks like special-casing '@classmethod' and '@staticmethod'.

我建议大家应该读读Guido van Rossum关于这个话题的博客——为什么外显的自我必须留下来。

When a method definition is decorated, we don't know whether to automatically give it a 'self' parameter or not: the decorator could turn the function into a static method (which has no 'self'), or a class method (which has a funny kind of self that refers to a class instead of an instance), or it could do something completely different (it's trivial to write a decorator that implements '@classmethod' or '@staticmethod' in pure Python). There's no way without knowing what the decorator does whether to endow the method being defined with an implicit 'self' argument or not. I reject hacks like special-casing '@classmethod' and '@staticmethod'.

Python不会强制你使用"self"。你可以给它起任何你想要的名字。你只需要记住方法定义头中的第一个参数是对对象的引用。

还有另一个非常简单的答案:根据python的禅宗，“显式比隐式好”。

我喜欢引用彼得斯的《Python禅》。“明确的比含蓄的好。”

在Java和c++中，'this。'可以被推导出来，除非你的变量名使它无法推导。所以你有时需要它，有时不需要。

Python选择显式地做这样的事情，而不是基于规则。

此外，由于没有隐含或假设任何内容，部分实现将被公开。自我。__class__进行自我。__dict__和其他“内部”结构可以以一种明显的方式使用。

这是为了最小化方法和函数之间的差异。它允许您轻松地在元类中生成方法，或在运行时向已存在的类添加方法。

e.g.

>>> class C:
...     def foo(self):
...         print("Hi!")
...
>>>
>>> def bar(self):
...     print("Bork bork bork!")
...
>>>
>>> c = C()
>>> C.bar = bar
>>> c.bar()
Bork bork bork!
>>> c.foo()
Hi!
>>>

它还(据我所知)使python运行时的实现更容易。