python functools

# functools模块
# update_wrapper(wapper, wrapped, assigned=WRAPPER_ASSIGNMENTS, updated=WRAPPER_UPDATES)
# 类似copy_properties功能
# wrapper包装函数，wrapped被包装函数
# 元组WRAPPER_ASSIGNMENTS中是要被覆盖的属性
# __model__(模块名),__name__(名字),__qualname__(限定名),__doc__(文档),__annotations(参数注解)__
# 元组WRAPPER_UPDATES中是要被更新的属性，__dict__属性字典
# 增加一个__wrapped__属性，保存wrapped函数
import functools
def logger(fn):
    def wrapper(*args, **kwargs):
        print(‘before‘)
        ret = fn(*args, **kwargs)
        print(‘after‘)
        return ret
    print(‘{} {}‘.format(id(wrapper), id(fn)))
    return functools.update_wrapper(wrapper, fn)    # update_wrapper返回值就是wrapper
@logger
def add(x, y):
    ‘‘‘
    This is a fun
    :param x: int
    :param y: int
    :return: int
    ‘‘‘
    ret = x + y
    return ret
print(‘1 -----------------------------------------‘)
print(add.__name__, add.__doc__, add.__qualname__, sep=‘\n‘)
print(id(add.__wrapped__))  # 被包装函数的内存地址
# functools模块
# wraps(wrapped, assigned = WRAPPER_ASSIGNMENTS, updated = WRAPPER_UPDATES) **消除装饰器副作用
# 类似copy_properties功能
# wrapped被包装函数
# 元组WRAPPER_ASSIGNMENTS中是要被覆盖的属性
# __model__(模块名),__name__(名字),__qualname__(限定名),__doc__(文档),__annotations(参数注解)__
# 元组WRAPPER_UPDATES中是要被更新的属性，__dict__属性字典
# 增加一个__wrapped__属性，保存wrapped函数
import functools
def logger(fn):
    @functools.wraps(fn)
    def wrapper(*args, **kwargs):
        print(‘before‘)
        ret = fn(*args, **kwargs)
        print(‘after‘)
        return ret
    print(‘{} {}‘.format(id(wrapper), id(fn)))
    return wrapper
@logger
def add(x, y):
    ‘‘‘
    This is a fun
    :param x: int
    :param y: int
    :return: int
    ‘‘‘
    ret = x + y
    return ret
print(‘2 -----------------------------------------‘)
print(add.__name__, add.__doc__, add.__qualname__, sep=‘\n‘)
print(id(add.__wrapped__))  # 被包装函数的内存地址
print(add(4, 40))