@classmethod装饰器 (The @classmethod Decorator)

The @classmethod decorator is an inbuilt function decorator that gets evaluated after the function is defined. The result of the evaluation shadows the function definition. The @classmethod's first argument is always a class cls, similar to an instance method receiving self as its first argument.

@classmethod装饰器是一个内置的函数装饰器，在定义函数后会对其进行评估。 评估结果遮盖了功能定义。 @classmethod的第一个参数始终是cls类，类似于将self作为其第一个参数的实例方法。

Syntax:

句法：

    Class ABC(object):
@classmethod
def function(cls, arg1, ...):
...

• Exists to create class methods that are passed with the actual class object within the function call.

  存在以创建在函数调用中与实际类对象一起传递的类方法。

• Bound to the class and not to an instance.

  绑定到类而不是实例。

• Can modify the class state and that would be applied across all the instances.

  可以修改类状态，并将其应用于所有实例。

@staticmethod装饰器 (The @staticmethod Decorator)

@staticmethods, similar to class methods, are methods that are bound to class rather than its object. However, they do not require a class instance creation. So, are not dependent on the state of the object.

与类方法类似， @staticmethods是绑定到类而不是对象的方法。 但是，它们不需要创建类实例。 因此，不依赖于对象的状态。

Syntax:

句法：

    Class ABC(object):
@staticmethod
def function(arg1, arg2, ...):
...

• Bound to the class and not to an instance

  绑定到类而不是实例

• Cannot modify the class state

  无法修改类状态

@classmethod和@staticmethod之间的比较 (Comparison between @classmethod and @staticmethod)

Class method	Static method
Takes cls as first parameter	Needs no specific parameters
Can access or modify the class state	Cannot access the class state
They must have parameters	Knows nothing about the class state. Are similar to utility methods.

类方法	静态方法
以cls作为第一个参数	不需要特定参数
可以访问或修改类状态	无法访问类状态
他们必须有参数	对类状态一无所知。 与实用程序方法相似。

@classmethod和@staticmethod的示例实现 (Example implementation of @classmethod and @staticmethod)

class City: 
def __init__(self, zip_code, name): 
self.zip_code = name 
self.name = name 
# a class method to create a city object. 
@classmethod
def city_name(cls, zip_code, name): 
return cls(zip_code, name) 
# a static method to check if a city is capital or not
@staticmethod
def isCapital(city_name): 
if city_name == 'bengaluru':
return True
if __name__ == '__main__':
bengaluru = City(560086, 'bengaluru')
mysuru = City.city_name(560111, 'mysuru')
print("city is {}".format(bengaluru.name))
print("city is {}".format(mysuru.name))
print("Bengaluru is capital :{}".format(City.isCapital('bengaluru')))

Output

输出量

city is bengaluru
city is mysuru
Bengaluru is capital : True

翻译自: https://www.includehelp.com/python/staticmethod-vs-classmethod.aspx