Learn Python Programming
Start with getting started, installation, and core basics. Clear explanations and practical examples to help you learn faster.
Python Variables and Literals
Variables store values in named containers. Python is dynamically typed — you don't declare types explicitly. The type is inferred from the assigned value and can change at any time.
Creating Variables
# Variables are created on first assignment (no declaration needed)
name = "Alice" # str
age = 25 # int
height = 5.7 # float
is_student = True # bool
grades = [90, 85, 92] # list
# Print values and their types
print(name, type(name)) # Alice <class 'str'>
print(age, type(age)) # 25 <class 'int'>
print(height, type(height)) # 5.7 <class 'float'>
print(is_student, type(is_student)) # True <class 'bool'>
# Multiple assignment
x, y, z = 1, 2, 3
a = b = c = 0 # all point to 0
# Swap values (no temp variable needed!)
x, y = y, x
print(x, y) # 2 1Naming Rules and Conventions
| Rule | Valid | Invalid |
|---|---|---|
| Must start with letter or underscore | name, _private | 1name, @var |
| Can contain letters, digits, underscores | user_name, item2 | user-name, my var |
| Case-sensitive | Name ≠ name | — |
| Cannot be a keyword | my_class | class, for, if |
Convention: Use snake_case for variables/functions, PascalCase for classes, UPPER_CASE for constants.
Numeric Literals
# Integers (no size limit in Python!)
decimal = 42
negative = -100
big = 1_000_000 # underscores for readability
binary = 0b1010 # 10
octal = 0o17 # 15
hexadecimal = 0xFF # 255
# Floats
pi = 3.14159
scientific = 2.5e3 # 2500.0
tiny = 1.2e-4 # 0.00012
# Complex numbers
z = 3 + 4j
print(z.real, z.imag) # 3.0 4.0
# Boolean (subclass of int)
print(True + True) # 2
print(False * 10) # 0String Literals
# Single and double quotes are identical
s1 = 'Hello'
s2 = "Hello"
# Triple quotes for multi-line strings
message = """This is a
multi-line string
that preserves newlines."""
# Raw strings (no escape processing)
path = r"C:\Users\name\folder" # backslashes are literal
# f-strings for formatting
name = "World"
greeting = f"Hello, {name}!"
# String operations
print(len(greeting)) # 13
print(greeting.upper()) # HELLO, WORLD!
print(greeting[0:5]) # HelloConstants (Convention Only)
# Python has no true constants — it is a CONVENTION to use UPPER_CASE
MAX_SIZE = 100
PI = 3.14159
DATABASE_URL = "postgresql://localhost/mydb"
# Nothing stops reassignment (but tools like mypy can warn)
# MAX_SIZE = 200 # works but violates conventionKey Takeaways
- Variables are created on assignment — no type declaration needed.
- Python is dynamically typed: a variable can hold any type and change type.
- Use
snake_casefor variables,UPPER_CASEfor constants. - Python integers have no size limit — they grow as large as memory allows.
- Use
type(x)to check a variable's type at runtime.
Frequently Asked Questions
Answers to common Python getting-started questions
Python Programming Tutorial — Learn Python from Scratch
Python is the world's most popular programming language for beginners, data science, AI/ML, web development, and automation. This tutorial teaches Python step-by-step with clear explanations and runnable code examples. You can try every example in our free Python Compiler without installing anything.
Each topic builds on the previous one, starting from installation and Hello World through advanced concepts like decorators, generators, and file I/O. Whether you are a complete beginner or refreshing specific skills, every page gives you immediately usable code.
What This Tutorial Covers
- Getting Started: Install Python, run online, Hello World
- Basics: Variables, data types, type conversion, input/output
- Operators: Arithmetic, comparison, logical, assignment
- Control Flow: if/elif/else, for loops, while, break/continue
- Data Structures: Lists, tuples, sets, dictionaries
- Strings: Methods, slicing, formatting, f-strings
- Functions: Parameters, return values, *args, **kwargs, scope
- OOP: Classes, objects, inheritance, polymorphism
- File I/O: Reading, writing, CSV, JSON handling
- Exceptions: try/except, custom exceptions, raise
- Advanced: List comprehensions, lambda, generators, decorators
- Modules: import, pip, packages, __name__ == "__main__"
Why Learn Python in 2026?
- #1 most popular language: Ranked first on TIOBE, Stack Overflow, and GitHub for multiple years running.
- AI and Data Science: The primary language for machine learning (TensorFlow, PyTorch, scikit-learn), data analysis (Pandas, NumPy), and AI development.
- Web development: Django and Flask power backends at companies like Instagram, Spotify, and Pinterest.
- Automation: Automate files, emails, web scraping, reports, and system administration tasks in minutes.
- Beginner-friendly: Clean syntax with enforced indentation makes code readable from day one — no curly braces or semicolons.
- Massive job market: Python developers are in high demand across tech, finance, healthcare, and research.
Python vs Other Languages
| Feature | Python | Java | JavaScript | C++ |
|---|---|---|---|---|
| Syntax | Very clean, readable | Verbose | Moderate | Complex |
| Typing | Dynamic, strong | Static, strong | Dynamic, weak | Static, strong |
| Speed | Slower (interpreted) | Fast (JIT) | Fast (V8 JIT) | Fastest (native) |
| Best For | AI/ML, data, automation | Enterprise, Android | Web frontend/backend | Systems, games |
| Learning Time | 2–4 weeks basics | 4–6 weeks basics | 3–4 weeks basics | 8–12 weeks basics |
How to Get Started
- Run Python online: Use our free Python Compiler — no installation needed.
- Install locally: Download Python 3 from
python.org(Windows/Mac) or useapt install python3(Linux). - Verify: Run
python3 --versionin your terminal to confirm installation. - Choose an editor: VS Code with Python extension (free), PyCharm Community (free), or Jupyter Notebook for data science.
- Follow this tutorial in order: Start from Introduction and work through each topic sequentially.
Frequently Asked Questions
No. Python is designed to be beginner-friendly. This tutorial starts from absolute zero and builds up gradually.
Python 3.10+ is recommended. Python 2 reached end-of-life in 2020. All examples in this tutorial use Python 3 syntax.
Basics (syntax, loops, functions) take 2–4 weeks. Intermediate (OOP, file I/O, modules) adds 3–4 weeks. Specialisation (Django, data science, ML) takes another 2–3 months.
Yes, completely free. No account, no sign-up. All topics and examples available without restriction.
Who Is This For?
Complete beginners choosing their first programming language. Students in CS courses needing a Python reference. Data analysts transitioning from Excel to Python (Pandas). Self-taught developers adding Python to their skill set. Professionals automating repetitive tasks. Anyone preparing for Python coding interviews.