python-examples/ObjectOrientedPython/InstanceVariables.py at master · dsabhrawal/python-examples · GitHub

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# Instance variables should be initialized before use

# There are three ways to initialize instance variables

# 1. Using Constructor 2. Using object 3. Using methods

class Student:

#Initializing using constructor

def __init__(self,name):

super().__init__()

self.name = name

#Initializing using methods

def defineAttributes(self,roll_no, age):

self.roll_no = roll_no

self.age = age

def display(self):

print('Name: ',self.name)

print('RollNo: ',self.roll_no)

print('Age: ',self.age)

print('Section: ',self.section)

s = Student('Student_A') #only name is initialized

#s.display() #will result into error

s.section='B' #section is initialized

s.defineAttributes(113,15) #roll no and age is initialized

s.display()

#Symbol table or special attribute __dict__ (holds dictionary of the instance variables)

print(s.__dict__) #Output: {'name': 'Student_A', 'section': 'B', 'roll_no': 113, 'age': 15}

#Deleting instance variables

del s.age

print(s.__dict__) #Output: {'name': 'Student_A', 'section': 'B', 'roll_no': 113}

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