CLASS in pyhton code example

Example 1: declare class python

# To create a simple class:
class Shape:
  	def __init__():
      	print("A new shape has been created!")
      	pass
    
    def get_area(self):
		pass

# To create a class that uses inheritance and polymorphism
# from another class:
class Rectangle(Shape):
  
	def __init__(self, height, width): # The constructor
    	super.__init__()
        self.height = height
    	self.width = width

	def get_area(self):
      	return self.height * self.width

Example 2: class python

class MyClass(object):
  def __init__(self, x):
    self.x = x

Example 3: what is an object in python

#objects are collections of data

Example 4: class in python

class ComplexNumber:
    def __init__(self, r=0, i=0):
        self.real = r
        self.imag = i

    def get_data(self):
        print(f'{self.real}+{self.imag}j')


# Create a new ComplexNumber object
num1 = ComplexNumber(2, 3)

# Call get_data() method
# Output: 2+3j
num1.get_data()

# Create another ComplexNumber object
# and create a new attribute 'attr'
num2 = ComplexNumber(5)
num2.attr = 10

# Output: (5, 0, 10)
print((num2.real, num2.imag, num2.attr))

# but c1 object doesn't have attribute 'attr'
# AttributeError: 'ComplexNumber' object has no attribute 'attr'
print(num1.attr)

Example 5: class in python

2+3j
(5, 0, 10)
Traceback (most recent call last):
  File "<string>", line 27, in <module>
    print(num1.attr)
AttributeError: 'ComplexNumber' object has no attribute 'attr'

Example 6: how to define a class in python

class a_class:
  #This initalizes the object, and is executed when you define
  #a new object in the class
  def __init__(self, input1):
    self.__input1 = input1
    
  #This is a function of the object that can be called
  def return_input(self):
    return self.__input1
  
a_class_object = a_class("input string")
print(a_class_object.return_input())