[Python] Implement public properties of Python classes

Background

Today I saw someone asking whether Python classes have characteristics similar to public attributes. That is, if the corresponding attributes of a certain instance are modified, the corresponding attributes of all instances of the class will be modified accordingly. I thought I thought about using an auxiliary singleton mode class to solve the problem.

Idea

Modify one instance and the other instance will also be modified accordingly. It sounds like the characteristics of the singleton mode, but it only targets one attribute, so you can borrow an auxiliary class.

Code

class Attr():
    attr = {}
    def __init__(self):
        self.__dict__ = self.attr
class Myclass():
    def __init__(self):
        self.attr = Attr()
    @property
    def value(self):
        return self.attr.value
    @value.setter
    def value(self, value):
        self.attr.value = value

Demo

In [47]: a = Myclass()

In [48]: b = Myclass()

In [49]: a.value = 1

In [50]: b.value
Out[50]: 1

In [51]: b.value = 2

In [52]: a.value, b.value
Out[52]: (2, 2)

Impression

Make use of design patterns and their combinations.

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