Python 装饰器

修饰器定义了新的本地函数，该函数将调用原始函数
一、函数修饰器

1、原始版

def positive_result(function):
    def wrapper(*args, **kwargs):      
         result = function(*args, **kwargs)
         assert result >=0 , function.__name__+ "() result isn't >=0 "
         return result
    wrapper.__name__ == function.__name__
    wrapper.__doc__ == function.__doc__
    return wrapper

2、优化v1, 使用functools简化，只是简单装饰器，装饰器本身无法传入参数

import functools
def positive_result(function):
     @functools.wraps(function)
     def wrapper(*args, **kwargs):
             print(args)
         result = function(*args, **kwargs)
         assert result >=0 , function.__name__+ "() result isn't >=0 "
         return result
     return wrapper

3、修饰器参数化，类似于@bounded(0, 5)

def bounded(minimum, maximum):
    def decorator(function):
        @functools.wraps(function)
        def wrapper(*args, **kwargs):
            result = function(*args, **kwargs)
            if result < minimum:
                return minimum
            elif result > maximum:
                return maximum
            return result
        return wrapper
    return decorator