Decorator Pattern 1



In [1]:

    
def mean(first, second, *rest):
    """평균값 반환 함수"""
    numbers = (first, second) + rest
    return sum(numbers) / len(numbers)

Tip. 튜플 결합



In [2]:

    
(1, 2) + (3,)









    Out[2]:





(1, 2, 3)

Decorator: 특정함수, 클래스, 메서드를 유일한 인자로 받음.



In [3]:

    
def float_args_and_return(function):
    def wrapper(*args, **kwargs):
        args = [float(arg) for arg in args]
        return float(function(*args, **kwargs))
    return wrapper



In [4]:

    
wrap_mean = float_args_and_return(mean)

중첩된 decorator
```
@decorator3
@decorator2
@decorator1
[function, method, class]
```
적용순서: [[[[function, method, class] -> @decorator1] -> @decorator2] -> @decorator3]

원본 함수의 속성값 소실문제



In [5]:

    
print(mean.__name__)
print(mean.__doc__)









    



mean
평균값 반환 함수



In [9]:

    
print(wrap_mean.__name__)
print(wrap_mean.__doc__)









    



wrapper
None



In [6]:

    
import functools



In [7]:

    
def float_args_and_return(function):
    @functools.wraps(function)  # __name__, __doc__ 승계, 디버깅에 유리
    def wrapper(*args, **kwargs):
        args = [float(arg) for arg in args]
        return float(function(*args, **kwargs))
    return wrapper



In [8]:

    
wrap_mean = float_args_and_return(mean)
print(wrap_mean.__name__)
print(wrap_mean.__doc__)









    



mean
평균값 반환 함수