想想这个例子:
class MyClass:
def func(self, name):
self.name = name
我知道self引用MyClass的特定实例。但是为什么func必须显式地包含self作为参数呢?为什么我们需要在方法的代码中使用self ?其他一些语言将其隐式化，或者使用特殊的语法。
有关设计决策的语言无关性考虑，请参见强制显式使用this/self指针的好处是什么?
要关闭OP省略方法的self形参并获得TypeError的调试问题，请使用TypeError: method()接受1个位置参数，但给出了2个。如果OP省略了self。在方法体中得到一个NameError，考虑如何在类中调用函数?
当前回答
这个参数的使用，通常称为self并不难理解，为什么它是必要的呢?或者为什么要明确地提到它?我想，对于大多数查找这个问题的用户来说，这是一个更大的问题，如果不是，他们在继续学习python时肯定会有同样的问题。我建议他们阅读以下几篇博客:
1:使用自我解释
注意，它不是关键字。
每个类方法(包括init)的第一个参数始终是对类当前实例的引用。按照惯例，这个参数总是命名为self。在init方法中，self指向新创建的对象;在其他类方法中，它引用被调用方法的实例。例如，下面的代码与上面的代码相同。
2:为什么我们要这样做，为什么我们不能像Java那样把它作为一个参数，而是用一个关键字来代替
我想补充的另一件事是，一个可选的self参数允许我在一个类中声明静态方法，不写self。
代码示例:
class MyClass():
def staticMethod():
print "This is a static method"
def objectMethod(self):
print "This is an object method which needs an instance of a class, and that is what self refers to"
PS:这只适用于Python 3.x。
在以前的版本中，您必须显式地添加@staticmethod装饰器，否则self参数是必须的。
其他回答
以下摘自关于self的Python文档:
As in Modula-3, there are no shorthands [in Python] for referencing the object’s members from its methods: the method function is declared with an explicit first argument representing the object, which is provided implicitly by the call. Often, the first argument of a method is called self. This is nothing more than a convention: the name self has absolutely no special meaning to Python. Note, however, that by not following the convention your code may be less readable to other Python programmers, and it is also conceivable that a class browser program might be written that relies upon such a convention.
有关更多信息，请参阅Python类文档教程。
The reason you need to use self. is because Python does not use special syntax to refer to instance attributes. Python decided to do methods in a way that makes the instance to which the method belongs be passed automatically, but not received automatically: the first parameter of methods is the instance the method is called on. That makes methods entirely the same as functions, and leaves the actual name to use up to you (although self is the convention, and people will generally frown at you when you use something else.) self is not special to the code, it's just another object.
Python could have done something else to distinguish normal names from attributes -- special syntax like Ruby has, or requiring declarations like C++ and Java do, or perhaps something yet more different -- but it didn't. Python's all for making things explicit, making it obvious what's what, and although it doesn't do it entirely everywhere, it does do it for instance attributes. That's why assigning to an instance attribute needs to know what instance to assign to, and that's why it needs self..
Self的作用类似于当前对象名或类的实例。
# Self explanation.
class classname(object):
def __init__(self,name):
self.name=name
# Self is acting as a replacement of object name.
#self.name=object1.name
def display(self):
print("Name of the person is :",self.name)
print("object name:",object1.name)
object1=classname("Bucky")
object2=classname("ford")
object1.display()
object2.display()
###### Output
Name of the person is : Bucky
object name: Bucky
Name of the person is : ford
object name: Bucky
这是为了遵循Python的禅宗“显式优于隐式”。它实际上是对类对象的引用。例如，在Java和PHP中，它被称为this。
如果user_type_name是你的模型中的一个字段，你可以通过self.user_type_name访问它。
我很惊讶居然没人提起Lua。Lua也使用“self”变量，但是可以省略，但仍然使用。c++对'this'做了同样的处理。我不认为有任何理由必须在每个函数中声明“self”，但你仍然可以像使用lua和c++一样使用它。对于一门以简洁为傲的语言来说，它要求你声明self变量是很奇怪的。
