Session Overview

Introduction

Python is a high-level, interpreted, and easy-to-learn programming language. It is widely used for web development, automation, data science, artificial intelligence, desktop applications, and scripting.

Installation

Download Python from the official website:

Download Python

Variables

A variable is a named memory location used to store data. Variables help us store and reuse values in a program.

variable_name = value

Example 1 : Store Text

name = "Shree"
print(name)

Shree

Example 2 : Store Number

age = 35
print(age)

35

Example 3 : Multiple Variables

name = "Shree"
city = "Mumbai"
age = 35
            
print(name)
print(city)
print(age)

Shree
Mumbai
35

Variable Naming Rules

• Can contain letters, numbers and underscore (_).
• Cannot start with a number.
• Variable names are case sensitive.
• Avoid Python keywords as variable names.

Valid Variable Names

name = "Shree"
student_name = "Vinayak"
age1 = 25

Invalid Variable Names

1name = "Shree"
student-name = "Vinayak"
class = "Python"

Data Types

Data Types define the type of value stored in a variable. Python automatically detects the data type based on the assigned value.

Common Data Types in Python

Data Type	Description	Example
int	Whole Numbers	10
float	Decimal Numbers	10.5
str	Text/String Values	"Python"
bool	True or False	True

Integer (int)

age = 25
print(age)

25

Float (float)

salary = 25000.50
print(salary)

25000.5

String (str)

course = "Python Django"
print(course)

Python Django

Boolean (bool)

is_active = True
print(is_active)

True

Finding Data Type using type()

name = "Shree"
age = 25
salary = 25000.50

print(type(name))
print(type(age))
print(type(salary))

<class 'str'>
<class 'int'>
<class 'float'>

Input / Output

Displaying Output using print()

print("Welcome to Python")

Welcome to Python

Accepting Input using input()

name = input("Enter Your Name : ")
print(name)

Enter Your Name : Shree
Shree

Input and Output Together

city = input("Enter City : ")
print("City :", city)

Enter City : Mumbai
City : Mumbai

Operators

Operators are special symbols used to perform operations on variables and values. Most operators in Python are similar to those used in C, C++, Java, C# and JavaScript.

Arithmetic Operators

Operator	Description	Example
+	Addition	10 + 5
-	Subtraction	10 - 5
*	Multiplication	10 * 5
/	Division	10 / 5
%	Modulus	10 % 3

num1 = 10
num2 = 5

print(num1 + num2)
print(num1 - num2)
print(num1 * num2)
print(num1 / num2)

15
5
50
2.0

Comparison Operators

Comparison operators are used to compare two values and return either True or False.

age = 18

print(age >= 18)
print(age < 18)

True
False

Logical Operators

Logical operators are used to combine multiple conditions.

age = 25
citizen = True

print(age >= 18 and citizen)

True

Conditional Statements

Conditional statements are used to execute different blocks of code based on a condition. They help programs make decisions.

if Statement

The if statement executes a block of code only when the condition is True.

age = 20
            
            if age >= 18:
                print("Eligible for Voting")

Eligible for Voting

if else Statement

The else block executes when the condition is False.

age = 15
            
            if age >= 18:
                print("Eligible for Voting")
            else:
                print("Not Eligible for Voting")

Not Eligible for Voting

if elif else Statement

The elif statement allows us to check multiple conditions.

marks = 75
            
            if marks >= 80:
                print("Grade A")
            elif marks >= 60:
                print("Grade B")
            elif marks >= 35:
                print("Grade C")
            else:
                print("Fail")

Grade B

Nested if Statement

An if statement can be placed inside another if statement.

age = 25
            citizen = True
            
            if age >= 18:
                if citizen:
                    print("Eligible to Vote")

Eligible to Vote

Quick Revision