1. What is Python?

Python is a high-level, general-purpose programming language created by Guido van Rossum and first released in 1991. Python is designed with a strong focus on readability and simplicity.

Python is widely used in web development, data science, artificial intelligence, machine learning, automation, scripting, scientific computing and software development.

Why Learn Python?

• Easy and readable syntax.
• Large collection of libraries and frameworks.
• Suitable for beginners and professionals.
• Used in Artificial Intelligence and Machine Learning.
• Supports object-oriented programming.
• Works on Windows, Linux and macOS.

2. Features of Python

Python provides several features that make it one of the most commonly used programming languages.

1. Simple Syntax

Python syntax is relatively simple and close to natural language.

2. Interpreted Language

Python programs are executed by the Python interpreter. Developers can run Python programs without explicitly compiling them into machine code first.

3. Dynamically Typed

The type of a variable is determined at runtime.

name = "John"
age = 25
salary = 45000.50

4. Object-Oriented

Python supports classes, objects, inheritance, encapsulation and polymorphism.

5. Large Standard Library

Python provides modules for file handling, mathematics, dates, operating system interaction, networking and many other tasks.

3. Installing Python

To start programming in Python, Python must first be installed on your computer.

Step 1: Install Python

Download and install Python using the official Python distribution for your operating system.

Step 2: Verify Installation

Open Command Prompt or Terminal and execute:

python --version

You may also use:

python3 --version

4. First Python Program

The simplest Python program prints a message to the screen using the print() function.

print("Hello, World!")

Understanding the Program

print() is a built-in Python function used to display information on the screen.

print("Welcome to ELearnHub")
print("Learn Python Programming")

5. Python Variables

A variable is a name used to store a value in memory. Python does not require explicit variable declarations.

name = "Rahul"
age = 22
marks = 85.5
is_passed = True

Python automatically determines the type of each value.

Variable Naming Rules

• A variable name can contain letters, numbers and underscore.
• A variable cannot start with a number.
• Variable names are case-sensitive.
• Python keywords cannot be used as variable names.

student_name = "Rahul"
studentAge = 21
marks1 = 90
_total = 100

1student = "Rahul"
student-name = "Rahul"

6. Python Data Types

A data type defines the kind of value stored in a variable.

Checking Data Type

age = 25

print(type(age))

7. Input and Output

Python provides the input() function for accepting data from the user.

name = input("Enter your name: ")

print("Hello", name)

By default, input() returns the entered value as a string.

Taking Numeric Input

age = int(input("Enter your age: "))

print("Your age is:", age)

8. Python Operators

Operators are symbols used to perform operations on values and variables.

Arithmetic Operators

a = 10
b = 3

print(a + b)
print(a - b)
print(a * b)
print(a / b)
print(a // b)
print(a % b)
print(a ** b)

Comparison Operators

a = 10
b = 20

print(a == b)
print(a != b)
print(a > b)
print(a < b)

Logical Operators

age = 25

print(age > 18 and age < 60)
print(age < 18 or age > 60)
print(not(age > 18))

9. Conditional Statements

Conditional statements allow a program to make decisions based on conditions.

if Statement

age = 20

if age >= 18:
    print("Eligible")

if-else Statement

age = 16

if age >= 18:
    print("Adult")
else:
    print("Minor")

if-elif-else

marks = 75

if marks >= 90:
    print("Grade A+")
elif marks >= 75:
    print("Grade A")
elif marks >= 60:
    print("Grade B")
else:
    print("Grade C")

10. for Loop

A for loop is used to iterate over a sequence or collection.

for number in range(1, 6):
    print(number)

Loop Through a List

names = ["Amit", "Rahul", "Priya"]

for name in names:
    print(name)

11. while Loop

A while loop repeatedly executes a block of code while a condition remains true.

count = 1

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

12. break and continue

break

The break statement immediately terminates a loop.

for number in range(1, 10):

    if number == 5:
        break

    print(number)

continue

The continue statement skips the current iteration and continues with the next iteration.

for number in range(1, 6):

    if number == 3:
        continue

    print(number)

13. Python Functions

A function is a reusable block of code designed to perform a specific task.

Creating a Function

def greet():
    print("Welcome to Python")

greet()

Function with Parameters

def greet(name):
    print("Hello", name)

greet("Rahul")

14. Function Parameters

Parameters allow a function to receive data from the calling code.

def add(a, b):

    result = a + b

    print("Sum =", result)


add(10, 20)

Default Parameter

def greet(name="Student"):
    print("Hello", name)

greet()
greet("Amit")

15. Return Values

A function can return a value using the return statement.

def add(a, b):

    return a + b


result = add(10, 20)

print(result)

16. Lambda Functions

A lambda function is a small anonymous function. It is useful when a simple function is required for a short operation.

square = lambda x: x * x

print(square(5))

The expression above creates a function that receives one value and returns its square.

17. Python Lists

A list is an ordered and mutable collection. Lists can contain multiple values.

students = ["Amit", "Rahul", "Priya"]

print(students)
print(students[0])

Adding an Item

students.append("Neha")

print(students)

Removing an Item

students.remove("Rahul")

print(students)

18. Python Tuples

A tuple is an ordered collection that cannot normally be modified after it is created.

coordinates = (10, 20)

print(coordinates)
print(coordinates[0])

19. Python Sets

A set is an unordered collection of unique values.

numbers = {10, 20, 30, 20, 10}

print(numbers)

Duplicate values are automatically removed.

20. Python Dictionaries

A dictionary stores data in key-value pairs.

student = {
    "name": "Rahul",
    "age": 21,
    "course": "MCA"
}

print(student["name"])
print(student["course"])

Adding a New Value

student["marks"] = 85

print(student)

21. Classes and Objects

Python supports object-oriented programming. A class defines the structure and behaviour of objects.

class Student:

    def display(self):
        print("This is a student")


student1 = Student()

student1.display()

Here, Student is the class and student1 is an object created from that class.

22. Constructor

The __init__() method is commonly used to initialize an object's data when the object is created.

class Student:

    def __init__(self, name, age):

        self.name = name
        self.age = age


student1 = Student("Rahul", 21)

print(student1.name)
print(student1.age)

23. Inheritance

Inheritance allows one class to acquire properties and methods from another class.

class Animal:

    def sound(self):
        print("Animal makes a sound")


class Dog(Animal):

    def bark(self):
        print("Dog barks")


dog = Dog()

dog.sound()
dog.bark()

24. Polymorphism

Polymorphism means that the same interface or method name can be used with different types of objects.

class Dog:

    def sound(self):
        print("Dog barks")


class Cat:

    def sound(self):
        print("Cat meows")


animals = [Dog(), Cat()]

for animal in animals:

    animal.sound()

25. Exception Handling

Exceptions are runtime errors that can interrupt program execution. Python provides try and except for handling exceptions.

try:

    number = int(input("Enter a number: "))

    result = 100 / number

    print(result)

except ValueError:

    print("Please enter a valid number.")

except ZeroDivisionError:

    print("Number cannot be zero.")

26. File Handling

Python provides built-in functions for creating, reading and modifying files.

Writing to a File

file = open("student.txt", "w")

file.write("Welcome to Python")

file.close()

Reading a File

file = open("student.txt", "r")

content = file.read()

print(content)

file.close()

Using with

The with statement is generally preferred because it handles closing the file automatically.

with open("student.txt", "r") as file:

    content = file.read()

    print(content)

27. Python Modules

A module is a Python file containing reusable functions, classes or variables.

Using a Built-in Module

import math

result = math.sqrt(25)

print(result)

Import Specific Function

from math import sqrt

print(sqrt(100))

28. Python Mini Project

Student Marks Calculator

Let's combine variables, input, arithmetic operators, conditions and functions to create a small student marks calculator.

def calculate_result(marks):

    total = sum(marks)

    percentage = total / len(marks)

    print("Total Marks:", total)

    print("Percentage:", percentage)


    if percentage >= 75:

        print("Grade: A")


    elif percentage >= 60:

        print("Grade: B")


    elif percentage >= 50:

        print("Grade: C")


    else:

        print("Grade: D")


marks = []

for i in range(3):

    mark = float(input("Enter marks: "))

    marks.append(mark)


calculate_result(marks)

Concepts Used

• Functions
• Lists
• Variables
• Input
• for loop
• Conditional statements
• Arithmetic operations

Python Course Summary

In this tutorial, you learned the fundamentals of Python programming and gradually moved toward object-oriented programming and practical development.

Topics Covered

• Introduction to Python
• Python Installation
• Variables and Data Types
• Input and Output
• Operators
• Conditional Statements
• Loops
• Functions
• Lists, Tuples, Sets and Dictionaries
• Classes and Objects
• Constructors
• Inheritance
• Polymorphism
• Exception Handling
• File Handling
• Modules
• Mini Project