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。
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..
它是对类实例对象的显式引用。
与Java或c++不同，Python不是为面向对象编程而构建的语言。
在Python中调用静态方法时，只需编写一个内部带有常规参数的方法。
class Animal():
def staticMethod():
print "This is a static method"
然而，一个对象方法，它需要你创建一个变量，在这里是Animal，它需要self参数
class Animal():
def objectMethod(self):
print "This is an object method which needs an instance of a class"
self方法还用于引用类中的变量字段。
class Animal():
#animalName made in constructor
def Animal(self):
self.animalName = "";
def getAnimalName(self):
return self.animalName
在本例中，self引用了整个类的animalName变量。记住:如果你在一个方法中有一个变量，self将不起作用。该变量仅在该方法运行时存在。为了定义字段(整个类的变量)，您必须在类方法之外定义它们。
如果你一个字都听不懂我在说什么，那么谷歌“面向对象编程”。一旦你明白了这一点，你甚至不需要问那个问题:)。
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。
“self”这个词指的是一个类的实例
class foo:
def __init__(self, num1, num2):
self.n1 = num1 #now in this it will make the perimeter num1 and num2 access across the whole class
self.n2 = num2
def add(self):
return self.n1 + self.n2 # if we had not written self then if would throw an error that n1 and n2 is not defined and we have to include self in the function's perimeter to access it's variables
