01 What is Python?
Python is a high-level, interpreted programming language known for its simplicity and readability. Used in web development, data science, AI, and automation.
# My first Python program print("Hello, World!") # Variables name = "CodeVerse" age = 25 print(name, age)
02 Data Types
Python has several built-in data types: strings, integers, floats, booleans, and None.
text = "Hello" # str number = 42 # int decimal = 3.14 # float is_true = True # bool nothing = None # NoneType print(type(text)) # <class 'str'>
03 Strings & f-Strings
Work with text using string methods, slicing, and formatted strings (f-strings).
name = "CodeVerse" # String methods print(name.upper()) # CODEVERSE print(len(name)) # 9 # f-Strings print(f"{name} is awesome!") # Slicing print(name[0:4]) # Code
04 Lists & Tuples
Lists are mutable sequences. Tuples are immutable. Both can store multiple items.
# List (mutable) fruits = ["apple", "banana", "cherry"] fruits.append("orange") fruits.remove("banana") print(fruits[0]) # apple # Tuple (immutable) colors = ("red", "green", "blue") print(colors[1]) # green
05 Dictionaries
Key-value pairs for structured data — fast lookups and flexible storage.
# Dictionary user = { "name": "Alex", "age": 25, "skills": ["Python", "HTML"] } print(user["name"]) # Alex user["email"] = "a@test.com"
06 Conditionals (if/elif/else)
Control program flow with conditional statements and comparison operators.
score = 85 if score >= 90: print("Excellent") elif score >= 70: print("Good") else: print("Fail") # Ternary result = "Pass" if score >= 50 else "Fail"
07 Loops (for & while)
Iterate over sequences with for loops and repeat actions with while loops.
# For loop fruits = ["apple", "banana", "cherry"] for fruit in fruits: print(fruit) # Range for i in range(5): print(i) # 0 1 2 3 4 # While loop count = 0 while count < 3: print(count) count += 1
08 Functions
Define reusable blocks of code with functions, parameters, and return values.
# Define function def greet(name, greeting="Hello"): return f"{greeting}, {name}!" # Call function print(greet("Alex")) # Hello, Alex! # Lambda function square = lambda x: x ** 2 print(square(5)) # 25
09 Object-Oriented Programming
Create classes and objects with attributes and methods. Learn inheritance and encapsulation.
# Class definition class Person: def __init__(self, name, age): self.name = name self.age = age def introduce(self): return f"I am {self.name}" # Create object p1 = Person("Alex", 25) print(p1.introduce())
10 File Handling
Read from and write to files using Python's built-in file operations.
# Write to file with open("file.txt", "w") as f: f.write("Hello, World!") # Read from file with open("file.txt", "r") as f: content = f.read() print(content)
11 Error Handling
Handle exceptions gracefully with try/except blocks to prevent crashes.
try: num = int(input("Enter a number: ")) result = 100 / num except ValueError: print("Please enter a valid number") except ZeroDivisionError: print("Cannot divide by zero") finally: print("Execution complete")
12 List Comprehension
Create new lists in a single line with Python's elegant comprehension syntax.
# List comprehension squares = [x**2 for x in range(10)] print(squares) # [0,1,4,9,16,25,36,49,64,81] # With condition evens = [x for x in range(20) if x % 2 == 0]
13 Modules & Imports
Organize code with modules and leverage Python's vast standard library.
# Import entire module import math print(math.sqrt(16)) # 4.0 # Import specific from datetime import datetime print(datetime.now()) # Import with alias import random as rnd print(rnd.randint(1, 10))
14 Best Practices
Write clean, Pythonic code following PEP 8 guidelines and industry standards.
✅ Snake Case
Use my_variable naming
✅ Docstrings
Document functions with """..."""
✅ Type Hints
def func(x: int) -> str:
✅ Virtual Env
Use venv for isolation
✅ PEP 8
Follow style guide
✅ List Comprehensions
Prefer over loops
✅ f-Strings
Use for formatting
✅ Context Managers
Use 'with' statements