python►b-OOP

Python-b01-Classes and Instances

This article shows the examples of Classes and Instances in python

OOP: Object-Oriented Programming

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# basic
class Employee:
    def __init__(self, first, last, pay):
        self.first = first
        self.last = last
        self.pay = pay
        self.email = first + '.' + last + '@company.com'

    def fullname(self):
        return '{} {}'.format(self.first, self.last)


emp_1 = Employee('Bob', 'Gobdo', 20)
print(emp_1.email)
print(emp_1.fullname())

# the same thing of fullname()
print(Employee.fullname(emp_1))

# class variables
class Employee:
    raise_amount = 2.04

    def __init__(self, first, last, pay):
        self.first = first
        self.last = last
        self.pay = pay
        self.email = first + '.' + last + '@company.com'

    def fullname(self):
        return '{} {}'.format(self.first, self.last)

    def apply_raise(self):
        self.pay = int(self.pay * self.raise_amount) # raise_amount is class vriable, we can remplace by Employee.raise_amount


emp_1 = Employee('Bob', 'Gobdo', 20)
print(emp_1.pay)        # 20
emp_1.apply_raise()
print(emp_1.pay)        # 40

print(Employee.__dict__)    # there is raise_amount inside
print(emp_1.__dict__)       # there is no raise_amount inside


# change raise_amount by instance
emp_1 = Employee('Bob', 'Gobdo', 20)
emp_2 = Employee('John', 'Youhs', 30)

emp_1.raise_amount = 3
print(Employee.raise_amount)    # 2.04
print(emp_1.raise_amount)       # 3
print(emp_2.raise_amount)       # 2.04

# change raise_amount by class
emp_1 = Employee('Bob', 'Gobdo', 20)
emp_2 = Employee('John', 'Youhs', 30)

Employee.raise_amount = 3
print(Employee.raise_amount)    # 3
print(emp_1.raise_amount)       # 3
print(emp_2.raise_amount)       # 3