#PYTHON(DAY19)class and object,_init_(),_str_() functions

 

#PYTHON(DAY19)

classes and objects

Python Classes/Objects

Python is an object oriented programming language.

Almost everything in Python is an object, with its properties and methods.

A Class is like an object constructor, or a “blueprint” for creating objects.

syntax

class classname():
   pass

creating object of a class

Now, we can use class name to create a object

x = classname()
print(type(x))

Example

class sample:
  x=5

print(sample)

And the output is:

<class '__main__.sample'>

y = sample()
print(y.x)

And the output is:

5

The __init__() Function

• init: is a special method, with a clear and definite functionality to assign values to our object properties and methods that might require these values, and in whole are require to create an object
• note class functions that start with’__’ are called as special methods. They executes a pre-defined functionality.

class Person:
  def __init__(self, name, age):
    self.name = name
    self.age = age

p1 = Person("John", 36)

print(p1.name)
print(p1.age)

And the output is:

John
36

The __str__() Function

The __str__() function controls what should be returned when the class object is represented as a string.

If the __str__() function is not set, the string representation of the object is returned:

class Person:
  def __init__(self, name, age):
    self.name = name
    self.age = age

  def __str__(self):
    return f"{self.name}({self.age})"    

p1 = Person("John", 36)

print(p1)

And the output is:

John(36)