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Today, I would like to share with you the python design pattern decorator pattern how to achieve the relevant knowledge, detailed content, clear logic, I believe that most people still know too much about this knowledge, so share this article for your reference, I hope you have something to gain after reading this article, let's take a look at it.

Decorator mode

What problem does the decorator mode solve?

Add new features without changing the original features and code

Optional and dynamically adjust the function according to different conditions

The decorator, as the name implies, is used to decorate other objects and to increase the function of the decorated object without changing the decorative object. This is like we buy a car, the same model, there are many functions are optional, but the core function of the car remains the same. When we buy, we can choose different configurations according to our needs.

How to achieve it?

Imagine that you are a decorator, if you want to decorate a car, then you first need to have a car, and in the decoration process, you can not change the original function (interface) of the car.

As shown in the class diagram:

The core function Core and all decorators must implement the Interface interface

All decorators save interface instances in a combined way

Class Core: def some_action (): passclass Decorator: def _ init__ (self,core): self.core = core def some_action ():.... Self.core.some_action () .python decorator syntax sugar

Decorators are too common, and python's special syntax candy simplifies the use of decorators. The outermost function receives a function object and returns the inner function, which is the true execution function.

# decorator definition def decorator (func): def wrapper (* args,**kwargs):. Result = func (* args,**kwargs).... The return result return wrapper # decorator uses @ decorator def func (): pass

Although the form has changed, the essence has not changed: save the interface instance and implement the same interface.

Saving the interface instance is easy to understand because the function func object is passed in.

How do you understand implementing the same interface? The operation of grammatical sugar @ xxxx is equivalent to func = decorator (func), which renames the inner function name.

These are all the contents of the article "how to implement the decorator pattern of the python design pattern". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.

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