[Python implements decorator mode]

"Python decorator" refers to a programming technique commonly used in the Python language that allows programmers to add additional functionality to a function without modifying its source code. It is essentially a function that returns a function, and is often used to modify or wrap the original function to enhance function functions and reuse code.

Decorator execution process

1. A decorator function takes a function as an argument and internally defines another function.
2. Call the original function in the inner function.
3. Where it is necessary to add functions to the original functions, write corresponding codes to achieve functional enhancements.
4. Returns the inner function.

Encoding implementation

def my_decorator(func):
    def wrapper():
        print("调用函数之前")
        func()
        print("调用函数之后")
    return wrapper

@my_decorator
def say_hello():
    print("Hello!")
    
# 调用被装饰后的函数
if __name__ == "__main__":
	say_hello()

output result

调用函数之前
Hello!
调用函数之后

Application Scenario

Python decorators can be used in many scenarios, such as:

• Timer: record function execution time;
• Cache: Cache the calculation results of functions to avoid repeated calculations;
• Permission verification: authenticate some functions that require permission;
• Logging: record the running log information of the function;
• Error handling: catch and handle exceptions when an error occurs in the function, etc.;

Using decorators can enhance code maintainability and scalability, and improve code reusability and flexibility.

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