Attributes Annotations
Using annotations starting with @
symbol is a special way to define properties.
- Write
@property
to defineget()
method; - Write
@attribute.setter
to define theset()
method for the attribute.
We need to do that to explain to Python what these methods are going to be used for.
1234567891011121314151617181920212223class Cat: def __init__(self, name = 'Kitty', age = 1): self.name = name self.__age = age self.__number_of_legs = 4 @property def age(self): return self.__age @age.setter def age(self, age): if isinstance(age, int) and 0<=age<=30: self.__age = age else: print('Invalid value of attribute age') cat = Cat('Maggie', 3) # Adding the wrong value cat.age = -100 cat.age = 5 print(cat.age)
Note
- First, define getter
@property
and after that – setter@attribute.setter
; - Both methods have the same name, that is equal to the attribute name;
- Now, to access the private attribute
__age
outside the class, you can use thecat.age
expression;
Var allt tydligt?
Tack för dina kommentarer!
Avsnitt 2. Kapitel 3
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Attributes Annotations
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Using annotations starting with @
symbol is a special way to define properties.
- Write
@property
to defineget()
method; - Write
@attribute.setter
to define theset()
method for the attribute.
We need to do that to explain to Python what these methods are going to be used for.
1234567891011121314151617181920212223class Cat: def __init__(self, name = 'Kitty', age = 1): self.name = name self.__age = age self.__number_of_legs = 4 @property def age(self): return self.__age @age.setter def age(self, age): if isinstance(age, int) and 0<=age<=30: self.__age = age else: print('Invalid value of attribute age') cat = Cat('Maggie', 3) # Adding the wrong value cat.age = -100 cat.age = 5 print(cat.age)
Note
- First, define getter
@property
and after that – setter@attribute.setter
; - Both methods have the same name, that is equal to the attribute name;
- Now, to access the private attribute
__age
outside the class, you can use thecat.age
expression;
Var allt tydligt?
Tack för dina kommentarer!
Avsnitt 2. Kapitel 3