python functools

# 做用：消除裝飾器反作用

# functools模塊
# update_wrapper(wapper, wrapped, assigned=WRAPPER_ASSIGNMENTS, updated=WRAPPER_UPDATES)
# 相似copy_properties功能
# wrapper包裝函數，wrapped被包裝函數
# 元組WRAPPER_ASSIGNMENTS中是要被覆蓋的屬性
# __model__(模塊名),__name__(名字),__qualname__(限定名),__doc__(文檔),__annotations(參數註解)__
# 元組WRAPPER_UPDATES中是要被更新的屬性，__dict__屬性字典
# 增長一個__wrapped__屬性，保存wrapped函數

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__))  # 被包裝函數的內存地址

# functools模塊
# wraps(wrapped, assigned = WRAPPER_ASSIGNMENTS, updated = WRAPPER_UPDATES) **消除裝飾器反作用
# 相似copy_properties功能
# wrapped被包裝函數
# 元組WRAPPER_ASSIGNMENTS中是要被覆蓋的屬性
# __model__(模塊名),__name__(名字),__qualname__(限定名),__doc__(文檔),__annotations(參數註解)__
# 元組WRAPPER_UPDATES中是要被更新的屬性，__dict__屬性字典
# 增長一個__wrapped__屬性，保存wrapped函數

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@loggerdef add(x, y):    '''    This is a fun    :param x: int    :param y: int    :return: int    '''    ret = x + y    return retprint('2 -----------------------------------------')print(add.__name__, add.__doc__, add.__qualname__, sep='\n')print(id(add.__wrapped__))  # 被包裝函數的內存地址print(add(4, 40))