1. Variables and Data Types

Variables are used to store information in Python.

name = "Daniel"
age = 25
height = 1.75
is_student = True

Common Python data types:

• int → Integer numbers
• float → Decimal numbers
• str → Text
• bool → True or False
• list → Ordered collection
• dict → Key-value collection

2. Input and Output

Programs become interactive when users can provide input.

name = input("Enter your name: ")
print("Hello", name)

input() receives user data. print() displays output.

3. Conditional Statements

Conditional statements allow programs to make decisions.

age = 18

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

Important keywords:

• if
• elif
• else

4. Loops

Loops repeat actions automatically.

For Loop

for i in range(5):
    print(i)

While Loop

count = 0

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

5. Functions

Functions help organize reusable code.

def greet(name):
    return f"Hello {name}"

print(greet("Daniel"))

Benefits of functions:

• Cleaner code
• Reusability
• Easier debugging
• Better scalability

6. Lists and Dictionaries

Python collections help store multiple values.

List Example

fruits = ["apple", "banana", "orange"]
print(fruits[0])

Dictionary Example

user = {
    "name": "Daniel",
    "age": 25
}

print(user["name"])

7. Object-Oriented Programming (OOP)

OOP organizes code using classes and objects.

class Dog:
    def __init__(self, name):
        self.name = name

    def bark(self):
        print("Woof!")

dog = Dog("Buddy")
dog.bark()

Key OOP concepts:

• Class
• Object
• Method
• Constructor
• Inheritance

8. Error Handling

Programs should handle errors gracefully.

try:
    num = int(input("Enter number: "))
    print(num)
except:
    print("Invalid input")

9. Modules and Packages

Python provides many built-in and external libraries.

import math

print(math.sqrt(16))

Install packages using pip:

pip install requests

Popular beginner libraries:

• requests
• pandas
• numpy
• selenium
• gradio

10. File Handling

Python can read and write files.

with open("test.txt", "w") as file:
    file.write("Hello Python")

File handling is useful for:

• Saving logs
• Reading datasets
• Generating reports
• Automation workflows

11. with … as

The with … as statement is used for safe resource management in Python.

It is commonly used with:

• Files
• Database connections
• Network connections
• Thread locks

File Example

with open("test.txt", "r") as file:
    content = file.read()
    print(content)