🌱

Basic

Interpreter · Installation · REPL · Comments

Week 1 — Getting Started with Python

Learn what Python is, install Python 3.10+ and VS Code, run your first print statement, and understand the difference between REPL and script mode.

installationREPLVS CodeHello World

Duration

⏱ 2 hours

Level

📊 Absolute Beginner

Prerequisite

🎯 None

OUTCOME

Run hello.py on your machine and evaluate expressions in REPL

What you'll learn

1Explain the difference between a programming language and an interpreter
2Install Python 3.10+ and VS Code
3Write and run your first Python program
4Understand the difference between REPL and script mode
5Use comments to document your code

1. What is Python?

Python is an interpreted language created by Guido van Rossum in 1991. Its human-readable syntax makes it one of the best first languages to learn.

Use cases

Web development (Django, FastAPI)
Data science & ML (Pandas, PyTorch)
Automation & scripting
Games, embedded systems, education

ℹ️

Interpreted vs compiled: Python runs code line-by-line, which is great for quick experiments but slower than C/Java.

2. Setting Up Your Environment

Install Python

https://www.python.org/downloads/
Version 3.10+ recommended
Windows: check "Add Python to PATH"
macOS: brew install python also works

bash

python --version    # Python 3.x.x
python3 --version   # macOS/Linux usually needs python3

Install VS Code

https://code.visualstudio.com/
Install the "Python" extension by Microsoft

3. Your First Program — Hello, World!

REPL (Interactive Mode)

Type python in the terminal → a >>> prompt appears → enter code and see results immediately.

python

>>> print("Hello, Python!")
Hello, Python!
>>> exit()

Script Mode

Save code to a .py file and run it. This is how real programs are built.

bash

python hello.py

4. Comments

Everything after # on a line is a comment — Python ignores it completely.

python

# Single-line comment
print("Running!")    # end-of-line comment

💡

Triple-quoted strings ("""...""") act as multi-line comments when not assigned to anything.

5. Common Mistakes

python not found on Windows — PATH not registered. Re-run installer and check "Add Python to PATH".
"SyntaxError: Missing parentheses" — you used Python 2 syntax. Python 3 always uses print("hello").
print(Hello) without quotes → NameError. Strings must be in "..." or '...'.

💻 Examples

Run these examples and check the output yourself.

01_hello.py— First output with print()

CODE

print("Hello, Python!")

▶ Output

Hello, Python!

02_multiple_print.py— Multiple lines of output

CODE

print("Name: Alice")
print("Age: 20")
print("Hobby: Coding")

▶ Output

Name: Alice
Age: 20
Hobby: Coding

03_comments.py— Comment styles

CODE

# Single-line comment
print("Hello!")    # inline comment

"""
This triple-quoted string
acts as a multi-line comment.
"""
print("Done.")

▶ Output

Hello!
Done.

📝 Exercises

Try them yourself first, then open the solution to compare.

Exercise 1

Environment Check

Goal: Verify Python and VS Code are installed correctly.

Requirements

Run python --version (must show 3.10+)
Install VS Code + Python extension
Submit screenshot of running print("Hello")

Grading

· Python 3.10+ installed — 50%
· VS Code runs code — 50%

Exercise 2

intro.py — Self-introduction

Goal: Print personal information using only print().

Requirements

File name: intro.py
Print: name / age / city / favorite language

Sample I/O

$ python intro.py
Name: Alice
Age: 20
City: Seoul
Language: Python

Grading

· All 4 items — 70%
· Correct format — 20%
· Correct filename — 10%

▶Toggle solution

SOLUTION

print("Name: Alice")
print("Age: 20")
print("City: Seoul")
print("Language: Python")

▶ Output

Name: Alice
Age: 20
City: Seoul
Language: Python

Example code / lecture materials

All lecture materials and example code are openly available on GitHub.

View on GitHub ↗