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
Self是对对象本身的引用，因此，它们是相同的。 Python方法不是在对象本身的上下文中调用的。 self在Python中可以用来处理自定义对象模型或其他东西。
其他回答
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..
我的小钱
在Person类中，我们用self定义了init方法，这里需要注意的有趣的事情是self和实例变量p的内存位置是相同的<__main__。位于0x106a78fd0>的Person对象
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def say_hi(self):
print("the self is at:", self)
print((f"hey there, my name is {self.name} and I am {self.age} years old"))
def say_bye(self):
print("the self is at:", self)
print(f"good to see you {self.name}")
p = Person("john", 78)
print("the p is at",p)
p.say_hi()
p.say_bye()
如上所述，self和实例变量都是同一个对象。
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。
自我，作为一个名字，只是一个惯例，你想怎么叫就怎么叫!但是当使用它时，例如删除对象，你必须使用相同的名称:__del__(var)，其中var在__init__(var，[…])中使用。
你也应该看一看cls，以获得更大的图景。这篇文章可能会有帮助。
首先，self是一个传统的名字，你可以用其他任何东西(连贯)来代替它。
它引用对象本身，因此当您使用它时，您声明.name和.age是您将要创建的Student对象(注意，不是Student类)的属性。
class Student:
#called each time you create a new Student instance
def __init__(self,name,age): #special method to initialize
self.name=name
self.age=age
def __str__(self): #special method called for example when you use print
return "Student %s is %s years old" %(self.name,self.age)
def call(self, msg): #silly example for custom method
return ("Hey, %s! "+msg) %self.name
#initializing two instances of the student class
bob=Student("Bob",20)
alice=Student("Alice",19)
#using them
print bob.name
print bob.age
print alice #this one only works if you define the __str__ method
print alice.call("Come here!") #notice you don't put a value for self
#you can modify attributes, like when alice ages
alice.age=20
print alice
代码在这里
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。
