Python中的静态类变量 [英] Static class variables in Python

问题描述

有可能在python中有静态类变量或方法吗？

Is it possible to have static class variables or methods in python? What syntax is required to do this?

推荐答案

在类定义中声明的变量，而不是方法中的变量是类或静态变量：

Variables declared inside the class definition, but not inside a method are class or static variables:

>>> class MyClass:
...     i = 3
...
>>> MyClass.i
3 

As @ millerdev 指出，这创建了一个类级别的i变量，但这与任何实例级别的 i变量，因此您可以有

As @millerdev points out, this creates a class-level "i" variable, but this is distinct from any instance-level "i" variable, so you could have

>>> m = MyClass()
>>> m.i = 4
>>> MyClass.i, m.i
>>> (3, 4)

这与C ++和Java不同，但与C＃无法使用对实例的引用访问静态成员。

This is different from C++ and Java, but not so different from C#, where a static member can't be accessed using a reference to an instance.

请参阅什么是Python教程对类和类对象的主题。

@Steve Johnson已经回答了有关静态方法，还记录在Python库参考中的内置函数 a>。

@Steve Johnson has already answered regarding static methods, also documented under "Built-in Functions" in the Python Library Reference.

class C:
    @staticmethod
    def f(arg1, arg2, ...): ...

@beidy建议 classmethod s over staticmethod，因为该方法接收类类型作为第一个参数，但我仍然有点模糊这种方法的优点超过静态方法。如果你也是，那么它可能没关系。

@beidy recommends classmethods over staticmethod, as the method then receives the class type as the first argument, but I'm still a little fuzzy on the advantages of this approach over staticmethod. If you are too, then it probably doesn't matter.

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