Scoring full marks in Python is easier than you think — here’s how!
These Introduction to Python Notes are specially designed for Class 9 AI students, presenting every concept in a simple and easy-to-understand manner. The notes help students grasp Python fundamentals quickly, build strong programming concepts, and gain the confidence needed to excel in exams.

These Python Class 9 Notes are not limited to theory alone. They include practical examples, solved programs, and multiple practice exercises for every topic, enabling students to develop their coding skills through hands-on learning. Whether you are preparing for examinations or learning Python for real-world applications, these notes provide the perfect balance of conceptual understanding and practical experience.

Start your Python journey today and make programming one of your strongest skills! 😊

Algorithm and Flowchart

How machine works?

Every machine, whether AI-enabled or not, performs tasks by following a set of instructions known as a program. These instructions guide the machine step by step to complete the task.
For example, a washing machine is designed to wash clothes and cannot perform unrelated tasks because it follows a predefined sequence of actions.

Write possible steps to wash cloths in a washing machine:

1. Put the dirty clothes into the washing machine.
2. Add detergent or washing powder.
3. Close the machine door properly.
4. Select the required washing mode.
5. Fill the machine with water.
6. Start the washing cycle.
7. The machine agitates and cleans the clothes.
8. Drain the dirty water.
9. Rinse the clothes with clean water.
10. Spin the clothes to remove excess water.
11. Stop the machine after the cycle is complete.
12. Remove the clean clothes from the machine.

Activity (Do It Yourself)

Write the possible steps to make Mango Juice.

How Are Programs Created for Machines?

1. Identify the Task – Determine what the machine needs to do.
2. Define the Goal – Clearly specify the main objective of the program.
3. Break the Task into Smaller Steps – Divide the main task into manageable sub-tasks.
4. Arrange the Steps Logically – Organize the steps in the correct sequence.
5. Create an Algorithm – Write a step-by-step solution to achieve the goal.
6. Draw a Flowchart – Represent the process visually to check the workflow.
7. Write the Program – Convert the algorithm into instructions that the machine can understand and execute.
8. Test and Improve – Check whether the program works correctly and make necessary improvements.

What is an Algorithm?

• An algorithm is a step-by-step set of instructions used to solve a problem or complete a task.
• It helps us perform tasks in the correct order to achieve the desired result.
• Before creating a computer program, we first write an algorithm to plan the solution.

An algorithm is a plan that tells us what to do, step by step.

1. Wash the mangoes properly.
2. Peel and cut the mangoes into pieces.
3. Put the mango pieces into a mixer/blender.
4. Add water and sugar as needed.
5. Switch on the mixer and blend the ingredients until smooth.
6. Pour the mango juice into a glass.
7. Mango juice is ready.

Activity (Do It Yourself)

Write Algorithm for making instant noodles.
Write Algorithm for turning on a computer

Important Note

• Different people may write algorithms in different ways.
• The steps can vary, but the final goal remains the same.
• An algorithm should be clear, logical, and easy to follow.

What is a Flowchart?

• A flowchart is a graphical or pictorial representation of an algorithm.
• It uses different symbols, shapes, and arrows to represent the steps of a process.
• Flowcharts help us understand, analyze, and communicate a process more easily.
• They show the sequence of steps in a clear and visual manner, making complex tasks easier to understand.

Common Flowchart Symbols

Symbol	Purpose
Terminal (Start/End)	Indicates the beginning or end of a flowchart.
Input/Output	Represents input given to or output received from a process.
Process	Represents an action, instruction, or operation.
Decision	Represents a condition that requires a Yes/No or True/False decision.
Arrow (Connector)	Shows the direction and flow of the process.

How to make Flowchart to represent Algorithm

Example: Find the Area of a Rectangle

Activity (Do It Yourself)

Write Algorithm and Flow Chart to:

1. Add two numbers
2. Check a number is even or odd
3. Display largest among three numbers
4. Check a number is prime or not
5. How traffic signal works

Introduction to Python

What is Program?

A computer program is a set of instructions that tells a computer how to perform a specific task. These instructions are written by a programmer using a programming language.

What is Python?

• Python is a programming language created by Guido Van Rossum in 1991.
• It is widely used for developing software and websites, analyzing data, performing scientific calculations, and building Artificial Intelligence (AI) applications.

Why Python for AI ? Characteristics of Python

• Easy to Learn and Use
  Python has a simple and easy-to-read syntax, making it beginner-friendly and easy to maintain.
• Large Standard Library
  Python provides many built-in libraries and functions that help solve a wide variety of problems quickly.
• Interactive Mode
  Python allows users to run and test code line by line, making learning, testing, and debugging easier.
• Portable and Compatible
  Python programs can run on different operating systems, such as Windows, Linux, and macOS, with little or no modification.
• Extensible
  Python can be combined with code written in other languages, allowing developers to add extra features and improve performance.
• Database Support and Scalability
  Python works with many databases and can be used to develop both small applications and large-scale projects.

Application of Python

• Web Development: Instagram, Spotify, Netflix
• Business Applications: Odoo, Triton, accounting software
• Games and 3D Graphics: Battlefield 2, The Sims 4, Blender
• Database Access: MySQL, PostgreSQL, Oracle databases
• Software Development: Buildbot, SCons, automated test scripts
• Desktop GUI Applications: Deluge, BitTorrent, desktop calculators

Download and Installing Python for use

How to Install Python?

Python IDE (IDLE)

Note: When we open IDLE, it starts in Interactive Mode by default, and the window that opens is called the Python Shell. It allows us to enter Python commands and see the results immediately.

Working Modes of Python

Python can be used in two modes:

1. Interactive Mode
2. Script Mode

Python Script/Program: Python statements written in a particular sequence to solve a problem is known as Python Script/Program.

Understanding First Python Program

Components of Python Program

Python Statements

A statement is an instruction written in a Python program that tells the computer to perform a specific task. Python executes statements one by one to produce the desired output.

Examples:

name = “Sanjay”
print(name)
X = 23

Multi-line Statements

Sometimes, long statements can be written across two or more lines. Such statements are called multi-line statements. Python allows multi-line statements using:

• Continuation character (\)
• Parentheses (())
• Square brackets ([])
• Braces ({})
• Semicolon (;)

Example:
total = 10 + 20 + 30 + \
        40 + 50

Output:
150

In the above example, the statement is written on two lines using the continuation character (\).

Example:

message = (“Artificial Intelligence ” \
           “is an exciting field.”)
print(message)

Output:
Artificial Intelligence is an exciting field.

Types of Multiline Statements

Type of Multi-line Statement	Usage	Example
Using Continuation Character (\)	Used to continue a statement on the next line.	result = 10 + 20 + 30 + \ 40 + 50 print(result) Output: 150
Using Parentheses ()	Statements inside parentheses can span multiple lines without using \.	total_marks = ( 85 + 90 + 88 + 92 + 95 ) print(total_marks) Output:450
Using Square Brackets []	Lists can be written across multiple lines for better readability.	subjects = [ “English”, “Maths”, “Science”, “Computer” ] print(subjects) Output: [‘English’, ‘Maths’, ‘Science’, ‘Computer’]
Using Braces {}	Sets or dictionaries can be spread across multiple lines.	colors = { “Red”, “Green”, “Blue”, “Yellow” } print(colors) Output: {‘Red’, ‘Green’, ‘Blue’, ‘Yellow’}
Using Semicolons (;)	Multiple statements can be written on a single line.	name = “Aman”; age = 15; grade = “10th” print(name, age, grade) Output: Aman 15 10th

Comments in Python

• Comments are pieces of text written inside a program.
• They are used to explain what a program or a block of code does.
• Comments do not affect the execution or output of the program.
• In Python, comments start with the # (hash) symbol.

Single-line Comment

A single-line comment is used to write a short note or explanation on a single line. It begins with the # symbol.

Example:

# Displaying a welcome message
print(“Welcome to Python”)

Output:

Welcome to Python

Multi-line Comment

A multi-line comment is used when the explanation is too long to fit on a single line. In Python, multi-line comments can be written using triple quotes (”’ ”’ or “”” “””).

Example:

“””
This program displays
a welcome message
on the screen.
“””
print(“Welcome to Python”)

Output:

Welcome to Python

Python Keywords

• Keywords are reserved words that have special meanings and predefined purposes in Python.
• Keywords cannot be used as variable names or identifiers.
• Python is case-sensitive, so keywords must be written exactly as defined.

Common Python Keywords

Identifiers

An identifier is a name given to entities like class, functions, variables, etc. It helps to differentiate one entity from another.

Rules for Identifiers:

• Composition: Identifiers can be a combination of letters in lowercase (a to z) or uppercase (A to Z) or digits (0 to 9) or an underscore _.
• Starting Character: An identifier cannot start with a digit. 1variable is invalid, but variable1 is perfectly fine.
• Keywords: Keywords cannot be used as identifiers.
• Special Symbols: We cannot use special symbols like !, @, #, $, % etc. in our identifier.
• Length: Identifier can be of any length.
• Case Sensitivity: Python is a case-sensitive language. This means Variable and variable are not treated the same.
• Meaningful Naming: Always name identifiers so that they make sense. While a statement like c = 10 is valid, writing count = 10 makes much more sense and makes it easier to figure out what the code does, even when you look back at it after a long gap.
• Multi-word Separation: Multiple words within a name can be separated using an underscore—for example, this_is_a_long_variable.

Variables

A variable is a named memory location used to store data in a program. It acts like a container that holds a value, which can be changed later if needed.

Example:

x = 42
y = 35

In the above example:

• x and y are variable names.
• 42 and 35 are the values stored in the variables.
• Python reserves memory to store these values.
• The values can be used or changed later in the program.

Note: The assignment operator (=) is used to assign a value to a variable.

Example:

x = 42

Here, the value 42 is assigned to the variable x.

How to change value of a variable?

name = “cbsesolutions.in”
print(name)
name = “best for cbse skill education”
print(name)

Output:
cbsesolutions.in
best for cbse skill education

How to Assign Same value to Different variables

x = y = z = 10
print(x,y,z)

Output:
10 10 10

In the above example:

The statement x = y = z = 10 assigns the value 10 to all three variables: a, b, and c.
All variables refer to the same value (10) in memory.

How to Assigning Different Values to Different Variables

x, y, z = 10, 20, 30
print(x,y,z)

Output:
10 20 30

In the above example:

The statement x,y,z = 10,20,30 assigns x = 10, y = 20, z = 30 (values are assigned in order)

Input and Output in Python

How to Input a value in a variable in Python

• In Python, the input() function is used to take input from the user through devices like a keyboard.
• By default, all input values are treated as strings (text).
• If required, we can convert the input into other data types like int, float, etc., using type conversion functions.

Examples

name = input(“Enter your full name: “) # stored as string
marks = input(“Enter your marks: “)   # stored as string
marks = int(input(“Enter your marks: “))  # converted to int

Output in Python

• Python uses the print() function to display output on the screen.
• It can display text, variables, or the result of expressions.
• The expression is evaluated first, and then the result is shown as output.

Examples of Input and Output in python

Write a program to accept Principal, Rate, and Time. Calculate and display Simple Interest.

Write a program to find addition of two numbers

Data Types in Python

• Every value in Python has a specific data type.
• Data type defines what kind of data a variable can store and what operations can be performed on it.

Type	Data Type	Use / Description	Example
Number	Integer (int)	Stores whole numbers without a decimal point.	age = 15
	Float (float)	Stores numbers with a decimal point.	marks = 89.5
Missing value	None	Represents the absence of a value.	result = None
Sequence	String (str)	Stores text or a sequence of characters enclosed in quotes.	name = “Sanjay”
	List (list)	Stores an ordered collection of multiple values. Lists are mutable (can be changed).	subjects = [“Python”, “AI”, “Math”]
	Tuple (tuple)	Stores an ordered collection of values that cannot be changed.	student = (101, “Sanjay”, 15)
Mapping	Set (set)	Stores an unordered collection of unique values. Duplicate values are automatically removed.	numbers = {1, 2, 2, 3, 3}
	Dictionary (dict)	Stores data as key-value pairs for quick retrieval.	student = {“name”:”Sanjay”, “age”:15}

Type Conversion in Python

• Type conversion refers to converting one type of data to another type.
• Type conversion can happen in two ways:
  • Explicit conversion
  • Implicit conversion

Explicit Conversion

• Explicit conversion also refers to type casting.
• In explicit conversion, programmer convert the data type of data to required data type.
• We use the predefined functions like int(), float(), str(), chr() etc to perform explicit type conversion.

Syntax

required_datatype(expression)

Example: Combining Roll Number and Student Name

roll_no = 25
student_name = “Riya”

print(“roll_no:”, type(roll_no))
print(“student_name:”, type(student_name))

# Converting integer to string
roll_no = str(roll_no)
print(“roll_no after conversion:”, type(roll_no))
student_info = roll_no + ” – ” + student_name
print(“Student Info:”, student_info)
print(“student_info:”, type(student_info))

Output

roll_no: <class ‘int’>
student_name: <class ‘str’>
roll_no after conversion: <class ‘str’>
Student Info: 25 – Riya
student_info: <class ‘str’>

Example Code	Sample Output	Explanation
python<br>price = 50<br>item = ” Pens”<br>print(str(price) + item)	50 Pens	str(price) converts the integer value into a string. It can then be combined with another string using the + operator.
python<br>marks = 89.7<br>bonus = 5<br>print(int(marks) + bonus)	94	int(marks) converts the float value into an integer by removing the decimal part. The addition is then performed.
python<br>count = 3<br>status = False<br>print(bool(count) + status)	1	bool(count) converts the integer into a Boolean value. Since count is non-zero, it becomes True (1). True + False gives 1.

Implicit conversion

• Implicit type conversion means Python automatically converts one data type into another without using any special function

Example:

# Code to calculate Simple Interest

principal = 3500
rate_of_interest = 6.2
time_period = 5

simple_interest = (principal * rate_of_interest * time_period) / 100

print(“datatype of principal amount : “, type(principal))
print(“datatype of rate of interest : “, type(rate_of_interest))
print(“value of simple interest : “, simple_interest)
print(“datatype of simple interest : “, type(simple_interest))

When we run the above program, the output will be:

datatype of principal amount : <class ‘int’>
datatype of rate of interest : <class ‘float’>
value of simple interest : 1085.0
datatype of simple interest : <class ‘float’>

Example Code	Sample Output	Explanation
a = 15 b = “World” print(a + b)	TypeError: unsupported operand type(s) for +: ‘int’ and ‘str’	The output shows an error because Python does not allow addition of integer and string directly without type conversion.
c = “Hi” n = 4 print(c * n)	HiHiHiHi	The string is repeated 4 times because the * operator repeats strings when used with an integer.
x = False y = 8 print(x + 10)	10	The boolean value False is treated as 0, so 0 + 10 = 10.
m = True n = 12 print(n – m)	11	The boolean value True is treated as 1, so 12 – 1 = 11.

Operators in Python

• An operator is a symbol used to perform mathematical or logical operations on values.
• The values on which an operator works are called operands.

Types of Operators

• Arithmetic operator
• Comprision (Relational) operator
• Assignment operator
• Logical operator
• Identity operator
• Membership operator
• operator

Note: As per your syllabus of class 9 AI you have to learn only four operators as give below:

Arithmetic Operators

Comparision (Relational) Operators

Logical Operator

Assignment Operator

Do it by yourself

1. Write a program to find average of five numbers
2. Write a program to find cube of a given number.
3. Write a program to convert ^oC to ^oF
4. Write a program to swap values of two variables

Flow of Control and Condition

Flow of Control

• The sequence in which program statements are executed is called the flow of control.
• sometimes we need the program to make decisions or repeat certain tasks. To do this, we use flow control statements.
• There are three main flow control statements in Python.
  • if statement
  • for statement
  • while statement

If Statement (Decision Making Statement)

In programming, a computer often needs to make decisions. Based on certain conditions, it decides which instructions should be executed next.
Decision-making statements help a program choose different actions according to different situations. Python provides the following decision-making statements:

• if statement
• if…else statement
• if…elif…else statement
• Nested if statement

if Statement

The if statement checks a condition. If the condition is True, the statements inside the if block are executed. If the condition is False, the statements are skipped.

Syntax

if condition:
    statement(s)

Example

num = int(input(“Enter a number”))
if num > 0:
    print(“Positive Number”)
print(“Program Ended”)

Output

Positive Number
Program Ended

Remember: The statements inside an if block must be indented.

if…else Statement

Sometimes we want one action to happen when a condition is True and another action when it is False. In such cases, we use the if…else statement.

Syntax

if condition:
    statement(s)
else:
    statement(s)

Example

age = int(input(“Enter your age”))
if age >= 18:
    print(“You can vote”)
else:
    print(“You cannot vote”)

Output

You cannot vote

if…elif…else Statement

When there are multiple conditions to check, we use if…elif…else. The word elif means else if.

Syntax

if condition1:
    statement(s)
elif condition2:
    statement(s)
else:
    statement(s)

Example

marks = int(input(“Enter your marks”))
if marks >= 90:
    print(“Grade A+”)
elif marks >= 75:
    print(“Grade A”)
else:
    print(“Grade B”)

Output

Grade A

Explanation

The first condition is False, but the second condition is True, so the elif block is executed.

 Nested if Statement

When an if statement is placed inside another if statement, it is called a Nested if Statement.

Example

num = float(input(“Enter a number”))
if num >= 0:
    if num == 0:
        print(“Zero”)
    else:
        print(“Positive Number”)
else:
    print(“Negative Number”)

Output

Positive Number

Do it yourself

1. Write a program to check a number is even or odd
2. Write a program to display largest among three numbers

The for Loop

A for loop is used when we want to repeat a block of code multiple times.

A for loop is mainly used to iterate over a sequence, such as a list or tuple. It takes each item from the sequence one by one and executes the associated block of code for each item until the sequence ends.

A sequence is an ordered collection of items, such as a list, string, or range of numbers.

Syntax

for variable in sequence:
    statement(s)

Example 1: Printing Numbers

for num in [1, 2, 3, 4, 5]:
    print(num)

Output

1
2
3
4
5

Example 2: Finding the Sum of Numbers

numbers = [6, 5, 3, 8, 4, 2, 5, 4, 11]
total = 0
for num in numbers:
    total = total + num
print(“The sum is”, total)

Output

The sum is 48

The range() Function

• The range() function is a built-in function in Python used to generate a sequence of integers within a specified range.
• It is commonly used with for loop to control how many times the loop should execute.

Syntax

range(start, stop, step)

Parameters of range()

• start → Specifies the starting value of the sequence. By default, it is 0.
• stop → Specifies the ending value of the sequence (not included in the output).
• step → Specifies the difference between consecutive values. By default, it is 1.

Examples

Example 1: Using only stop

for i in range(5):
    print(i)

Output

0
1
2
3
4

Example 2: Using start and stop

for i in range(2, 6):
    print(i)

Output

2
3
4
5

Example 3: Using start, stop, and step

for i in range(2, 11, 2):
    print(i)

Output

2
4
6
8
10

The while Loop

A while loop is used to repeatedly execute a block of code as long as a given condition remains True.

A while loop is useful when we do not know in advance how many times the loop needs to run.

Syntax

while condition:
    statement(s)

How a while Loop Works

In a while loop, the condition (test expression) is checked first.

• If the condition is True, the statements inside the loop are executed.
• After executing the loop body once, the condition is checked again.
• The loop continues to execute as long as the condition remains True.
• When the condition becomes False, the loop stops.

Example

i = 1
while i <= 5:
    print(i)
    i = i + 1

Output

1
2
3
4
5

Example: Sum of Natural Numbers

n = 10
total = 0
i = 1
while i <= n:
    total = total + i
    i = i + 1
print(“The sum is”, total)

Output

The sum is 55

Do it yourself

1. Write a program to find numbers which are divisible by 7 and multiple of 5 between 1200 and 2200.
2. Write a program to find the whether a number is prime or not using ‘while’ loop.

break statement in Python

The break statement is used to exit a loop immediately, even if the loop condition is still True. When a break statement is encountered, the loop stops and control moves to the first statement after the loop.

Example

for i in range(1, 10):
    if i == 4:
        break
    print(i)

Output

1
2
3

The continue Statement

The continue statement is used to skip the remaining statements of the current iteration and move directly to the next iteration of the loop.

Example

for i in range(1, 6):
    if i == 3:
        continue
    print(i)

Output

1
2
4
5

Introduction to List

• A List is collection of multiple values stored in one place under a single name.
• The values stored in a list are called elements or items.
• All elements of list are separated by commas.
• A list is enclosed within square brackets [ ].
• A list can have any number of items and may of different types (integer, float, string etc.)
• List is ordered, which means items are stored in a specific sequence.
• List is mutable, which means their contents can be changed after creation.

Creating List

Creating Empty List

# Empty list
empty_list = []
print(empty_list)

Output
[]

Creating List of Integers

# list1 stores prime numbers
list1 = [2, 3, 5, 7, 11, 13]
print(list1)

Output
[2, 3, 5, 7, 11, 13]

Creating List of Strings

# list2 stores fruit names
list2 = [‘Apple’, ‘Mango’, ‘Banana’, ‘Orange’]
print(list2)

Output
[‘Apple’, ‘Mango’, ‘Banana’, ‘Orange’]

List with Mixed Data Types

# list3 stores different data types
list3 = [101, 85.6, “Python”]
print(list3)

Output
[101, 85.6, ‘Python’]

Accessing Elements of a List

Python provides two ways to access individual elements of a list:

1. Positive Indexing (List Index)
2. Negative Indexing

Positive Indexing (List Index)

• Each item in a list has a position called an index.
• Indexing starts from 0.
• The first item has index 0, the second item has index 1, and so on.
• To access an item, we use the index operator [ ].

Negative Indexing

Python also allows negative indexing to access elements from the end of the list.

• -1 refers to the last item.
• -2 refers to the second last item and so on.

Item	Apple	Mango	Orange	Banana
Index	0	1	2	3
Negative Index	-4	-3	-2	-1

Example: Accessing Elements

fruits = [“Apple”, “Mango”, “Orange”, “Banana”]
print(fruits[0])
print(fruits[2])

print(fruits[-1])
print(fruits[-2])

Output

Apple
Orange

Banana
Orange

Task	Sample Code and Output
Accessing Elements Using List Index	fruits = [“Apple”, “Mango”, “Orange”, “Banana”] print(fruits[0]) print(fruits[2])  Output: Apple Orange
Using a Non-Integer Index	fruits = [“Apple”, “Mango”, “Orange”, “Banana”] print(fruits[2.0])  Output: TypeError: list indices must be integers or slices, not float
Accessing Elements in a Nested List	student = [“Rahul”, [85, 90, 88]] print(student[0][2]) print(student[1][1])  Output: h 90
Accessing Elements Using Negative Indexing	colors = [“Red”, “Blue”, “Green”, “Yellow”] print(colors[-1]) print(colors[-4])  Output: Yellow Red

Adding Elements to a List

Elements can be added to a list using the following methods:

1. append()
2. insert()
3. extend()

append() Method

• The append() method adds a single element to the end of the list.
• append() adds only one element at a time

Example

numbers = [10, 20, 30]
print(“Original List:”, numbers)
numbers.append(40)
print(“Updated List:”, numbers)

Output

Original List: [10, 20, 30]
Updated List: [10, 20, 30, 40]

insert() Method

• The insert() method adds an element at a specified position in the list.
• insert() requires two arguments:
  • Position (index)
  • Value to be inserted

Syntax

list_name.insert(index, value)

Example

numbers = [10, 20, 30]
print(“Original List:”, numbers)
numbers.insert(1, 15)
print(“Updated List:”, numbers)

Output

Original List: [10, 20, 30]
Updated List: [10, 15, 20, 30]

extend() Method

• The extend() method is used to add multiple elements at the end of a list.
• The new elements are added at the end of the list.

Example

numbers = [10, 20, 30]
print(“Original List:”, numbers)
numbers.extend([40, 50, 60])
print(“Updated List:”, numbers)

Output

Original List: [10, 20, 30]
Updated List: [10, 20, 30, 40, 50, 60]

Removing Elements from a List

Elements can be removed from a list using the following methods:

1. remove()
2. pop()

remove() Method

• The remove() method removes the specified element from the list.
• If the element appears multiple times, only the first occurrence is removed.
• An error occurs if the specified element is not present in the list.

Syntax

list_name.remove(value)

Example

fruits = [“Apple”, “Mango”, “Orange”, “Banana”]
print(“Original List:”, fruits)
fruits.remove(“Orange”)
print(“Updated List:”, fruits)

Output

Original List: [‘Apple’, ‘Mango’, ‘Orange’, ‘Banana’]
Updated List: [‘Apple’, ‘Mango’, ‘Banana’]

Using pop() Method

• The pop() method removes and returns an element from the list.
• If no index is specified, pop() removes the last element of the list.

Syntax

list_name.pop(index)

Example 1: Removing an Element at a Specific Position

fruits = [“Apple”, “Mango”, “Orange”, “Banana”]
print(“Original List:”, fruits)
fruits.pop(1)
print(“Updated List:”, fruits)

Output

Original List: [‘Apple’, ‘Mango’, ‘Orange’, ‘Banana’]
Updated List: [‘Apple’, ‘Orange’, ‘Banana’]

Example 2: Removing the Last Element

fruits = [“Apple”, “Mango”, “Orange”, “Banana”]
fruits.pop()
print(fruis)

Output

[‘Apple’, ‘Mango’, ‘Orange’]

Slicing of a List

• Slicing is used to access a specific element from a list by specifying a range of indexes.
• In Python, slicing is performed using the colon (:) operator.

Syntax

list_name[start : end]

• start → Starting index (included)
• end → Ending index (not included)

Common Forms of Slicing

Expression	Description
list[:end]	Elements from the beginning up to end-1
list[start:]	Elements from start to the end
list[start:end]	Elements from start to end-1
list[:]	Creates a copy of the entire list
list[::-1]	Returns the list in reverse order

Examples of List Slicing

Consider the following list:

colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”]

Task	Sample Code and Output
Slicing a Range of Elements	colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”] print(colors[1:4])  Output:   [‘Blue’, ‘Green’, ‘Yellow’]
Accessing Elements from a Specific Index to the End	colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”] print(colors[3:])  Output:   [‘Yellow’, ‘Black’, ‘White’]
Printing the Entire List	colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”] print(colors[:])  Output:   [‘Red’, ‘Blue’, ‘Green’, ‘Yellow’, ‘Black’, ‘White’]
Slicing Using Negative Indexes	colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”] print(colors[-4:-1])  Output:   [‘Green’, ‘Yellow’, ‘Black’]
Accessing Elements from the Beginning Using Negative Index	colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”] print(colors[:-2]) Output:   [‘Red’, ‘Blue’, ‘Green’, ‘Yellow’]
Printing the List in Reverse Order	colors = [“Red”, “Blue”, “Green”, “Yellow”, “Black”, “White”] print(colors[::-1])  Output:   [‘White’, ‘Black’, ‘Yellow’, ‘Green’, ‘Blue’, ‘Red’]

List Methods and Built-in Functions

Method / Function	Description	Example
len()	Returns the total number of elements in the list.	list1 = [“CBSE”, “Solutions”, “Python”] print(len(list1)) Output: 3
append()	Adds a single element at the end of the list.	list1 = [“CBSE”, “Solutions”] list1.append(“Notes”) print(list1) Output: [‘CBSE’, ‘Solutions’, ‘Notes’]
extend()	Adds all elements of another list to the end.	list1 = [“CBSE”] list1.extend([“Solutions”, “Python”]) print(list1) Output: [‘CBSE’, ‘Solutions’, ‘Python’]
insert()	Inserts an element at a specific position.	list1 = [“CBSE”, “Python”] list1.insert(1, “Solutions”) print(list1) Output: [‘CBSE’, ‘Solutions’, ‘Python’]
count()	Returns number of occurrences of an element.	list1 = [“CBSE”, “Python”, “CBSE”] print(list1.count(“CBSE”)) Output: 2
index()	Returns index of first occurrence of an element.	list1 = [“CBSE”, “Solutions”, “Python”] print(list1.index(“Python”)) Output: 2
remove()	Removes first occurrence of an element.	list1 = [“CBSE”, “Solutions”, “Python”, “Solutions”] list1.remove(“Solutions”) print(list1) Output: [‘CBSE’, ‘Python’, ‘Solutions’]
pop()	Removes and returns element at given index (last if not specified).	list1 = [“CBSE”, “Solutions”, “Python”] print(list1.pop()) print(list1) Output: Python [‘CBSE’, ‘Solutions’]
reverse()	Reverses the order of elements in the list.	list1 = [“CBSE”, “Solutions”, “Python”] list1.reverse() print(list1) Output: [‘Python’, ‘Solutions’, ‘CBSE’]
sort()	Sorts the list in ascending order (in-place).	list1 = [“Python”, “CBSE”, “AI”] list1.sort() print(list1) Output: [‘AI’, ‘CBSE’, ‘Python’]