静态方法如何访问 Python 中的类变量？
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How can static method access class variable in Python?
提问by daydreamer
This is what my code looks like
这就是我的代码的样子
class InviteManager():
ALREADY_INVITED_MESSAGE = "You are already on our invite list"
INVITE_MESSAGE = "Thank you! we will be in touch soon"
@staticmethod
@missing_input_not_allowed
def invite(email):
try:
db.session.add(Invite(email))
db.session.commit()
except IntegrityError:
return ALREADY_INVITED_MESSAGE
return INVITE_MESSAGE
When I run my tests, I see
当我运行测试时，我看到
NameError: global name 'INVITE_MESSAGE' is not defined
How can I access INVITE_MESSAGEinside @staticmethod?
如何进入INVITE_MESSAGE内部@staticmethod？
采纳答案by Fred Foo
You can access it as InviteManager.INVITE_MESSAGE, but a cleaner solution is to change the static method to a class method:
您可以作为 访问它InviteManager.INVITE_MESSAGE，但更简洁的解决方案是将静态方法更改为类方法：
@classmethod
@missing_input_not_allowed
def invite(cls, email):
return cls.INVITE_MESSAGE
(Or, if your code is really as simple as it looks, you can replace the whole class with a bunch of functions and constants in a module. Modules are namespaces.)
（或者，如果你的代码真的像看起来那么简单，你可以用一个模块中的一堆函数和常量替换整个类。模块是命名空间。）
回答by Maciej Gol
Try:
尝试：
class InviteManager():
ALREADY_INVITED_MESSAGE = "You are already on our invite list"
INVITE_MESSAGE = "Thank you! we will be in touch soon"
@staticmethod
@missing_input_not_allowed
def invite(email):
try:
db.session.add(Invite(email))
db.session.commit()
except IntegrityError:
return InviteManager.ALREADY_INVITED_MESSAGE
return InviteManager.INVITE_MESSAGE
The InviteManageris in the scope of it's staticmethods.
这InviteManager是在它的静态方法的范围内。
回答by daydreamer
Just realized, I needed @classmethod
刚刚意识到，我需要 @classmethod
class InviteManager():
ALREADY_INVITED_MESSAGE = "You are already on our invite list"
INVITE_MESSAGE = "Thank you! we will be in touch soon"
@classmethod
@missing_input_not_allowed
def invite(cls, email):
try:
db.session.add(Invite(email))
db.session.commit()
except IntegrityError:
return cls.ALREADY_INVITED_MESSAGE
return cls.INVITE_MESSAGE
You can read about it here
你可以在这里阅读
回答by Maxime Lorant
You can access to yours attributes with InviteManager.INVITE_MESSAGEand InviteManager.ALREADY_INVITED_MESSAGEwithout changing anything in their declaration.
您可以在更改InviteManager.INVITE_MESSAGE或InviteManager.ALREADY_INVITED_MESSAGE不更改声明中的任何内容的情况下访问您的属性。
回答by Neeraj Bansal
Simply, understand the concept of class level variables/methods and instance level variables/methods.
简单来说，理解类级变量/方法和实例级变量/方法的概念。
While working with static methods, you won't use selfkeyword as selfkeyword is used to represent instance of the class or to use instance variables of the class. In fact one use class_name, see below example:
在使用静态方法时，您不会使用self关键字，因为self关键字用于表示类的实例或使用类的实例变量。实际上一个使用class_name，见下面的例子：
class myclass():
msg = "Hello World!"
@staticmethod
def printMsg():
print(myclass.msg)
myclass.printMsg() #Hello World!
print(myclass.msg) #Hello World!
myclass.msg = "Hello Neeraj!"
myclass.printMsg() #Hello Neeraj!
print(myclass.msg) #Hello Neeraj!
