Programming Python - 1. Preview -1.3 Stepping up to OOP

OOP: Structure, Encapsulation, Customization

1. Using Classes

class Person:
    def __init__(self, name, age, pay=0, job=None):
        self.name=name
        self.age=age
        self.pay=pay
        self.job=job

if __name__=='__main__':
    bob=Person('bob smith', 42, 30000, 'software')
    sue=Person('sue jones',45, 45000,'hareware')
    print(bob.name, sue.pay)

    print(bob.name.split()[-1])
    sue.pay *= 1.1
    print(sue.pay)

2. Adding Behavior

 

#class Person
class Person:
    def __init__(self, name, age, pay=0, job=None):
        self.name=name
        self.age=age
        self.pay=pay
        self.job=job
    def lastname(self):
        return self.name.split()[-1]
    
    def giveRaise(self, percent):
        self.pay *= (1+percent)

if __name__=="__main__":
    bob=Person('bob smith', 42, 30000, 'software')
    sue=Person('sue jones', 45, 50000, 'hardware')

    print(bob.name, sue.pay)
    print(bob.lastname())
    sue.giveRaise(0.1)
    print(sue.pay)

 

 

 Adding Inheritance

from person import Person

class Manager(Person):
    def giveRaise(self, percent, bonus=0.1):
        self.pay*=(1+percent+bonus)

if __name__=='__main__':
    tom=Manager(name='tom doe', age=50, pay=50000)
    print(tom.lastname())
    tom.giveRaise(0.2)
    print( tom.pay)

 

 

Alternative implementation

class Person:
    def __init__(self, name, age, pay=0, job=None):
        self.name=name
        self.age=age
        self.pay=pay
        self.job=job
    
    def lastName(self):
        return self.name.split()[-1]
    
    def giveRaise(self, percent):
        self.pay *= (1+percent)
    def __str__(self):
        return ('%s => %s: %s, %s' % (self.__class__.__name__, self.name, self.job, self.pay))

class Manager(Person):
    def __init__(self, name, age, pay):
        Person.__init__(self, name,age, pay, 'Manager')
    def giveRaise(self, percent, bonus=0.1):
        Person.giveRaise(self, percent+bonus)

if __name__=='__main__':
    bob=Person('bob smith', 44)
    sue=Person('sue jones', 47, 40000, 'manager')
    tom=Manager(name='tom doe', age=50, pay=50000)
    print(sue, sue.pay, sue.lastName)

    for obj in (bob, sue, tom):
        obj.giveRaise(0.1)
        print(obj)

 

 

Adding Persistence

#make_db_classes
import shelve
from person import Person
from manager import Manager

bob=Person('bob smith', 42, 3000, 'software')
sue=Person('sue jones', 45, 4000, 'hardware')
tom=Manager('tom doe', 50, 5000)

db=shelve.open('class-shelve')
db['bob']=bob
db['sue']=sue
db['tom']=tom

db.close()

 

 

#dump_db_classes
import shelve
db=shelve.open('class-shelve')

for key in db:
    print(key, '=>\n', db[key].name, db[key].pay)

bob=db['bob']
print(bob.lastname())
print(db['tom'].lastname)

 

 

 

#update_db_classes
import shelve
db=shelve.open('class-shelve')

sue=db['sue']
sue.giveRaise(.25)
db['sue']=sue


tom=db['tom']
tom.giveRaise(.20)
db['tom']=tom
db.close()