인프런 파이썬 중급 - 클래스&메소드 심화

 

 

In [1]:

# 클래스 구조

class Car():
    """
    Car class
    Author : Kim
    Date : 2021.04.25
    """
    
    # 클래스 변수(모든 인스턴스가 공유)
    car_count = 0
    
    def __init__(self, company, details):
        self._company = company
        self._details = details
        Car.car_count += 1
    
    def __str__(self):
        return 'str : {} - {}'.format(self._company, self._details)
    
    def __repr__(self):
        return 'repr : {} - {}'.format(self._company, self._details)
    
    def __del__(self):
        Car.car_count -= 1
    
    
    def detail_info(self):
        print('Current ID : {}'.format(id(self)))
        print('Car Detail Info : {} {}'.format(self._company, self._details.get('price')))
        
        

car1 = Car('Ferrari',{'color':'White','horsepower':400,'price':8000})
car2 = Car('BMW',{'color':'Black','horsepower':270,'price':5000})
car3 = Car('AUDI',{'color':'Silver','horsepower':300,'price':6000})
    

In [2]:

print(id(car1))
print(id(car2))
print(id(car3))

 

1861401257440
1861401257536
1861401257488

In [3]:

print(car1._company == car2._company)
print(car1 is car2)

 

False
False

In [4]:

# dir & __dict__
# __dict__는 

In [5]:

print(dir(car1))

 

['__class__', '__del__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_company', '_details', 'car_count', 'detail_info']

In [6]:

print(car1.__dict__)

 

{'_company': 'Ferrari', '_details': {'color': 'White', 'horsepower': 400, 'price': 8000}}

In [7]:

print(Car.__doc__)

 

    Car class
    Author : Kim
    Date : 2021.04.25
    

In [8]:

car1.detail_info()
car2.detail_info()

 

Current ID : 1861401257440
Car Detail Info : Ferrari 8000
Current ID : 1861401257536
Car Detail Info : BMW 5000

In [9]:

print(car1.__class__, car2.__class__)
print(id(car1.__class__), id(car2.__class__))

 

<class '__main__.Car'> <class '__main__.Car'>
1861390010688 1861390010688

In [10]:

Car.detail_info()

 

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-10-05da48ebdf49> in <module>
----> 1 Car.detail_info()

TypeError: detail_info() missing 1 required positional argument: 'self'

In [11]:

Car.detail_info(car1)

 

Current ID : 1861401257440
Car Detail Info : Ferrari 8000

In [12]:

car1.car_count

Out[12]:

3

In [13]:

Car.car_count

Out[13]:

3

In [14]:

del car2
print(Car.car_count)

 

2

In [15]:

# 인스턴스 네임스페이스에 없으면 상위에서 검색
# 즉, 동일한 이름으로 변수 생성 가능 -> 인스턴스 검색 후 상위 클래스 변수, 부모클래스 변수

In [26]:

# 기본 인스턴스 메소드

# 클래스 선언
class Car(object):
    '''
    Car Class
    Author : Me
    Date : 2021.04.26
    Description : Class, Static, Instance Method
    '''
    
    # Class Variable (모든 인스턴스가 공유)
    car_count = 0
    price_per_raise = 1.0

    def __init__(self, company, details):
        self._company = company
        self._details = details
        
        
    def __str__(self):
        return 'str : {} - {}'.format(self._company, self._details)

    def __repr__(self):
        return 'repr : {} - {}'.format(self._company, self._details)

    # Instance Method
    # self : 객체의 고유한 속성 값 사용
    def detail_info(self):
        print('Current Id : {}'.format(id(self)))
        print('Car Detail Info : {} {}'.format(self._company, self._details.get('price')))
                
    
    def get_price(self):
        return 'Before Car Price -> company : {}, price : {}'.format(self._company, self._details.get('price'))
    
    def get_price_culc(self):
        return 'After Car Price -> company : {}, price : {}'.format(self._company, self._details.get('price')*Car.price_per_raise)
    
    @classmethod
    def raise_price(cls, per):
        if per<= 1:
            print("please enter 1 or more")
            return
        cls.price_per_raise = per
        print('Succeed! price increased')

    @staticmethod
    def is_bmw(inst):
        if inst._company == "Bmw":
            return 'OK! This car is {}'.format(inst._company)
        return 'Sorry. This car is not Bmw'
    
    
# 자동차 인스턴스    
car1 = Car('Bmw', {'color' : 'Black', 'horsepower': 270, 'price': 5000})
car2 = Car('Audi', {'color' : 'Silver', 'horsepower': 300, 'price': 6000})

In [27]:

car1.detail_info()

 

Current Id : 1861402149360
Car Detail Info : Bmw 5000

In [28]:

print(car1._details.get('price'))

 

5000

In [29]:

# 가격정보(인상 전)
print(car1.get_price())

 

Before Car Price -> company : Bmw, price : 5000

In [30]:

Car.price_per_raise = 1.4

In [31]:

print(car1.get_price_culc())

 

After Car Price -> company : Bmw, price : 7000.0

In [32]:

Car.raise_price(1.6)

 

Succeed! price increased

In [33]:

print(car1.get_price_culc())

 

After Car Price -> company : Bmw, price : 8000.0

In [34]:

print(car1.is_bmw(car1))

 

OK! This car is Bmw

In [35]:

print(Car.is_bmw(car1))
print(Car.is_bmw(car2))

 

OK! This car is Bmw
Sorry. This car is not Bmw