class MyClass:
x = 5
p1 = MyClass()
# 5
print(p1.x)
print("---")
# built-in __init__() function is called on object instatiation
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
p1 = Person("John", 36)
# John, 36
print(p1.name)
print(p1.age)
print("===")
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def myfunc(self):
print("Hello my name is " + self.name)
p1 = Person("John", 36)
# Hello my name is John
p1.myfunc()
#36
print(p1.age)
# Set property
p1.age = 40
# 40
print(p1.age)
# <class '__main__.Person'>
# So this tells us it is an object of type Person
print (type(p1))
# Delete an object
del p1
# A class with no definition
class Person:
pass
print("******")
# Inheritance, Parents, Children
# First define a class
class Person:
def __init__(self, fname, lname):
self.firstname = fname
self.lastname = lname
def printname(self):
print(self.firstname, self.lastname)
x = Person("John", "Doe")
# John Doe
x.printname()
# Now create a child of the parent
class Student(Person):
pass
y = Student("Sarah", "Smith")
# Sarah Smith
y.printname()
print("------------")
# Notice that we never defined a method called printname() in the child class
# But the Student inherited the methods of the parent class (Person)
class Student(Person):
def __init__(self, fname, lname):
#add properties here
pass
y = Student("Sarah", "Smith")
# This next line breaks because we over-rode the inheritance of the parent
# by defining our own __init__() function in the chil
# In other words, the child's __init__() function overrides the inheritance
# of the parent's __init()__ function
#y.printname()
# We fix it by adding a call to the parent's __init__() function
class Student(Person):
def __init__(self, fname, lname):
Person.__init__(self, fname, lname)
y = Student("Sarah", "Smith")
# Now this works
# Sarah Smith
y.printname()
print("------------")
# By using super() we automatically inherit the methods and properties from parent
class Student(Person):
def __init__(self, fname, lname):
super().__init__(fname, lname)
self.graduationyear = 2019
y = Student("Sarah", "Smith")
# Sarah Smith
y.printname()
# 2019
print (y.graduationyear)
print("============")
# Make graduationyear a variable
class Student(Person):
def __init__(self, fname, lname, year):
super().__init__(fname, lname)
self.graduationyear = year
y = Student("Sarah", "Smith", 2022)
# Sarah Smith
y.printname()
# 2022
print (y.graduationyear)
print("<><><><><><>")
# Add a method
class Student(Person):
def __init__(self, fname, lname, year):
super().__init__(fname, lname)
self.graduationyear = year
def welcome(self):
print("Welcome", self.firstname, self.lastname, "to the class of", self.graduationyear)
