Get and Set

Getter and setter are methods for non-direct access to the attributes:

get() (getter) returns the value of the private attribute;
set() (setter) sets the value.

These methods are called properties.

You can implement them by defining two additional methods:


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class Cat:
  def __init__(self, name = 'Kitty', age = 1):
    self.name = name
    self.__age = age
    self.__children = 0 

  # Getter
  def get_age(self):
    return self.__age

  # Setter
  def set_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)
# Wrong value
cat.set_age(-23) 
cat.set_age(8)
print(cat.get_age())

Note

We added data validation inside the set_age() method. Only the correct integer value can be assigned to the attribute.

Everything was clear?

Section 2. Chapter 2