(i) Destructor is a special method gets execution automatically when an object exits from the scope.

(ii) In Python,__ __ _del ( ) method is used as destructor.

(i) "init" is a special function begin an end with double underscore in Python act as a Constructor.

(ii) Constructor function will automatically executed when an object is created

General format of init method (Constructor function)

def init_(self, [args .......]):

<statements>

Once a class is created, next to create an object or instance of that class. The process of creating

object is called as "Class Instantiation":

Syntax :

Object_name = class_name( )

The class instantiation uses function notation

ie. class_name with ().

(i) Class is the main building block in Python.

(ii) Class is a template for the object.

(i) In Python, a set is another type of collection data type. A Set is a mutable and an unordered collection of elements without duplicates.

(ii) That means the elements within a set cannot be repeated. This feature used to include membership testing and eliminating duplicate elements.

Syntax:

Tuple_ Name= ( ) #Empty tuple

Tuple_ Name = (E1, E2,E2........En) #Tuple with n number elements

Tuple_ Name = E1, E2, E3.........En # Elements of a tuple without parenthesis

A list in Python is known as a "sequence data type like strings. It is an ordered collection of values enclosed within square brackets [ ]. Each value of a list is called as element.

Constructor:

(i) Constructor is the special function that is automatically executed when an object of a class is created. In Python, there is a special function called init" which act as a Constructor

(ii) It must begin and end with double underscore.

General format of constructor :

General format of__init__method

(Constructor function)

def_init__(self, [args......]):

<statements>

Destructor :

(i) Destructor is also a special method to destroy the objects.

(ii) In Python, __del_) method is used as destructor. It is just opposite to constructor

Code :

class Sample:

def init(self, n1, n2):

self._n1=n1

self._n2=n2

def sum(self):

print ("Class Variable 1:",self._nl)

print ("Class Variable 2:", self. n2)

print ("Sum:", self._nl + self. _n2)

S=Sample (5,10)

S.sum ()

Output :

Class Variable 1: 5

Class Variable 2: 10

Sum: 15

Variables defined inside a class are called as"Class Variable" and functions are called as "Methods. Class variable and methods are together known as members of the class. The class members should be accessed through objects or instance of class. A class can be defined anywhere in a Python program

Defining classes : In Python, a class is defined by using the keyword class. Every class has a unique name followed by a colon (: ).

Syntax for Defining a Class :

class class_name:

statement_1

statement_2

........................

........................

statement_n

(i) List is an ordered set of elements. But, a dictionary is a data structure that is used for matching one element (Key) with another (Value).

(ii) The index values can be used to access a particular element. But, in dictionary key represents index and key may be a number of a string.

(iii) Lists are used to look up a value whereas a dictionary is used to take one value and look up another value.

Set Operations :

(i) Union : It includes all elements from two or more sets.

(ii) Intersection : It includes the common elements in two sets.

(iii) Difference: It includes all elements that are in first set (say set A) but not in the second set (say set B).

(iv) Symmetric difference : It includes all the elements that are in two sets (say sets A and B)but not the one that are common to two sets.

Sort ():

It sorts the element in list.

Syntax :

List.sort(reverse=True|False, key=myFunc)

Sorts the element in list :

Both arguments are optional

i. If reverse is set as True, list sorting is in descending order.

ii. Ascending is default.

iii. Key=myFunc; "myFunc" - the name of the user defined function that specifies the
sorting criteria.

Example :

My List=[Thilothamma', "Tharani, 'Anitha', SaiSree', 'Lavanya]

My List.sort( )

print(My List)

My List. sort(reverse=True)

print(My List)

Output:

['Anitha', Lavanya, 'SaiSree', Tharani', "Thilothamma']

(Thilothamma', "Tharani, "SaiSree', Lavanya', Anitha']

i. The elements of a list are changeable (mutable) whereas the elements ofa tuple are unchangeable (immutable), this is the key difference between tuples and list.

ii. The elements of a list are enclosed within square brackets. But, the elements of a tuple are enclosed by parenthesis.

iii Iterating tuples is faster than list.

Constructor:

(i) Constructor is the special function that is automatically executed when an object of a class is created. In Python, there is a special function called init which act as a Constructor.

(ii) It must begin and end with double underscore. This function will act as an ordinary function; but only difference is, it is executed automatically when the object is created.

(iii) This constructor function can be defined with or without arguments. This method is used to initialize the class variables

General format of init method

(Constructor function)

def_init_(self, [args .....):

<statements>

In the class "Sample", there is a constructor that takes one parameter called num.

When the constructor runs:

(i) first prints "Constructor of class Sample..."

(ii) Then it assigns the value passed (for

example, 10) to the variable self.num.

(iii) Finally, it prints "The value is: 10"

The constructor runs automatically when you

create an object

Output :

Constructor of class Sample...

The value is : 10

Class variable defined within constructor keep count of number of objects created with the class

Destructor :

(i) Destructor is also a special method to destroy the objects.

(ii) In Python, _del( ) method is used as destructor. It is just opposite to constructor

Example :

class Sample :

num =0

def init_(self, var):

Sample.num + = 1

self.var =var

print("The object valueis =", self.var)

print("The value of classvariable is=",

Sample.num)

def del_(self):

Sample.num-=1

print("Object with value %d is exit

from the scope"%self.var)

SI = Sample(15)

S2 = Sample(35)

S3 = Sample(45)

del S1, S2, S3

Set operations: The. set operation in Python are Union, Intersection, difference and symmetric difference.

Union: It includes all elements from two or more sets

(i) In python, the operator | is used to union of two sets. The function union( )is also used to join two sets in python.

(ii) Example : Program to Join (Union) two sets using union operator

set_ A={2,4,6,8}

set_ B={'A', 'B', 'C', 'D'}

U_ set=set_ A set_ B

print(U_ set)

Output :

{2, 4,6, 8, 'A','D','C', 'B'}

Intersection :

(i) It includes the common elements in two sets

(ii) The operator & is used to intersect two sets in python. The function intersection() is also used to intersect two sets in python.

(iii) Example : Program to insect two sets using intersection operator

set_ A={'A', 2, 4, 'D'}

set_ B={'A', 'B, 'C','D'}

print(set_ A & set_ B)

Output :

{'A', 'D'}

Difference :

(i) It includes all elements that are in first set (say set A)but not in the second set (say set B)

(ii) The minus ( operator is used to difference set operation in python. The function difference( ) is also used to difference operation.

(iii) Example : Program to difference of two sets using minus operator

set_ A={'A', 2, 4, 'D'}

set_ B={'A', 'B', 'C','D'}

print(set_ A - set_ B)

Output : {2, 4}

Symmetric difference :

i. It includes all the elements that are in two sets (say sets A and B)but not the one that are common to to sets.

(i) The caret (^) operator is used to symmetric difference set operation in python. The function symmetric difference( ) is also used to do the same operation.

(ii) Example :Program to symmetric difference of two sets using caret operator

set_ A={'A', 2,4, 'D'}

set_ B={'A', 'B,'C', 'D'}

print(set_ A ^ set_ B)

Output :

{2, 4, 'B', 'C'}

The range( ) is a function used to generate a series of values in Python. Using range( ) function, you can create list with series of values. The range( ) function has three arguments.

Syntax of range ( ) function:

range (start value, end value, step value)

where,

I. start value - beginning value (default = 0).

II. end value - upper limit.

III. step value interval between values. Example: Generating whole numbers upto 5 for x in range (1, 6):

print(x)

Output :

1

2

3

4

5

i. List ( ) is used to convert a range into a list.

ii. Syntax: List_ Variable= list (range ( ) )

iii. Example :

>>>Even_ List = list(range(2,1 1,2))

>>> print(Even_ List)

Output : (2, 4, 6, 8, 10)

(iv) In the above code, list() function takes the result of range( ) as Even_ List elements. Thus, Even_ List list has the elements of first five even numbers.

Series of values can be created using range ( ) function.

Example : Generating squares of first 10 natural numbers

Squares = [ ]

for x in range(1,1 1):

S=x** 2

squares. append(s)

print (squares)

Output : [1,4, 9, 16, 25, 36, 49, 64, 81, 100]

Inserting elements in a list using insert ( ):

(i) append) function in Python is used to add more elements in a list. But, it includes elements at the end of a list.
(ii) If you want to include an element at your desired position, you can use insert) function. The insert() function is used to insert an element at any position of a list.

Syntax :

List. insert (position index, element)

Example:

>>> My List=(34,98,47, Kannan, 'Gowrisankar', 'Lenin', 'Sreenivasan' ]

>>> print(My List)

[34, 98, 47, 'Kannan', 'Gowrisankar', 'Lenin,' Sreenivasan']

>>>My List. insert(3,'Ramakrishnan')

>>> print(My List)

[34, 98, 47, 'Ramakrishnan', Kannan' 'Gowrisankar', Lenin', 'Sreenivasan']

Output: [34, 98, 47, 'Ramakrishnan', 'Kannan', 'Gowrisankar, Lenin', 'Sreenivasan']

(i) In the above example, insert( ) function inserts a new element 'Ramakrishnan' at the index value 3, ie. at the 4th position.

(ii) While inserting a new element in between the existing elements, at a particular location, the existing elements shifts one position to the right.