python

Decorator

Define the decorator: The decorator function wraps another function (func) with extra behavior before and after calling it.

def my_decorator(func):
    def wrapper():
        print("Before the function runs")
        func()
        print("After the function runs")
    return wrapper

@my_decorator
def say_hello():
    print("Hello!")

say_hello()

Before the function runs
Hello!
After the function runs

json.dumps(): 对象→JSON字符串（内存中）

json.loads(): JSON字符串→对象（内存中）

json.dump(): 对象→JSON文件

json.load(): JSON文件→对象