30 Days Of Python — User Guide

1. Quick Start

30 Days Of Python is a structured, 30-day programming challenge that teaches Python from absolute beginner to intermediate level through daily lessons with hands-on exercises. Each day introduces a focused topic — from variables and operators through web scraping, APIs, and data analysis — with annotated code examples and practice problems.

Key features:

• 30 progressive daily lessons covering the full Python fundamentals spectrum
• Hands-on .py example files for every topic with inline comments explaining each line
• Practice exercises and challenges at the end of each day
• Sample Flask web application demonstrating Python for web development
• Real-world datasets (CSV, JSON, TXT) for data manipulation exercises
• Available in 7 languages: English, Chinese, Korean, German, Spanish, Persian, Portuguese
• Covers modern Python libraries including NumPy, Pandas, Flask, and MongoDB

Prerequisites: Python 3.6 or higher installed on your system.

Get started in 2 minutes:

git clone https://github.com/Asabeneh/30-Days-Of-Python.git
cd 30-Days-Of-Python
python 01_Day_Introduction/helloworld.py

Hello World!
5
1
6
5
1
6
2.0
3.0
3.5
3
1
3
9
<class 'int'>
<class 'float'>
<class 'complex'>
<class 'str'>
<class 'list'>
<class 'dict'>
<class 'set'>

Tip

Start with Day 1 and progress sequentially. Each day builds on the previous day's concepts — skipping days may leave gaps in your understanding.

What to try next:

• Open the Day 1 markdown lesson (01_Day_Introduction) for the full walkthrough
• Move to Day 2 to learn about variables and built-in functions
• Check the python_for_web/ directory for the Flask web application example

2. Installation

System Requirements

Getting the Repository

HTTPS

git clone https://github.com/Asabeneh/30-Days-Of-Python.git

SSH

git clone git@github.com:Asabeneh/30-Days-Of-Python.git

GitHub CLI

gh repo clone Asabeneh/30-Days-Of-Python

Verifying Python Installation

python --version

Python 3.13.0

Important

On some systems, Python 3 is invoked with python3 instead of python. If python --version shows Python 2.x or is not found, try python3 --version.

Installing Dependencies for the Web Project

The Day 26 Flask web application requires additional packages:

cd python_for_web
pip install -r requirements.txt

Optional Dependencies for Later Days

These packages are covered in the later lessons but are not included in a requirements file. Install them as you reach the relevant day:

Warning

The requirements.txt in python_for_web/ pins older versions of Flask and its dependencies. If you encounter compatibility issues with newer Python versions, consider creating a virtual environment (covered in Day 23) and installing the pinned versions there.

Post-Install Verification

Run the Day 1 example to confirm everything works:

python 01_Day_Introduction/helloworld.py

If you see Hello World! followed by arithmetic results, your setup is complete.

3. Configuration

This project requires no configuration for most lessons. The only configurable setting is in the Flask web application:

To change the port:

export PORT=8080
python python_for_web/app.py

Note

The Flask app runs with debug=True by default. This is appropriate for learning but should never be used in production. See the Admin Guide for deployment considerations.

4. Core Usage

Following the 30-Day Curriculum

The course is organized into 30 daily directories, each containing:

• A markdown lesson (XX_topic.md) with explanations, diagrams, and examples
• A Python script (day_X.py or similar) with executable example code
• Exercises at the end of each lesson to practice

Daily workflow:

1. Read the day's markdown file for concepts and explanations
2. Run the corresponding .py file to see examples in action
3. Complete the exercises at the end of the lesson
4. Move to the next day

Curriculum Overview

Running Code Examples

Each day's Python file can be run directly:

python 03_Day_Operators/day-3.py

Addition:  3
Subtraction:  1
Multiplication:  6
Division:  2.0
Division:  3.0
Division:  3.5
Division without the remainder:  3
Modulus:  1
Division without the remainder:  2
Exponential:  9

Tip

Use the Python interactive shell (python or python3) to experiment with individual code snippets from the lessons. Copy-paste examples and modify them to deepen understanding.

Working with Custom Modules (Day 12)

The repository includes two example modules that demonstrate Python's import system:

mymodule.py (root directory):

from mymodule import generate_full_name, sum_two_nums, person, gravity

12_Day_Modules/main.py demonstrates importing:

cd 12_Day_Modules
python main.py

Asabneh Yetayeh
10
100
981.0
{'firstname': 'Asabeneh', 'age': 250, 'country': 'Finland', 'city': 'Helsinki'}
Asabeneh

Working with the Package Example (Day 20)

The mypackage/ directory demonstrates creating Python packages with __init__.py:

mypackage/
├── __init__.py
├── arithmetics.py    # add_numbers, subtract, multiple, division, remainder, power
└── greet.py          # greet_person

from mypackage.arithmetics import add_numbers, subtract, power
from mypackage.greet import greet_person

print(add_numbers(1, 2, 3))          # 6
print(subtract(10, 3))               # 7
print(power(2, 8))                   # 256
print(greet_person('John', 'Doe'))   # John Doe, welcome to 30DaysOfPython Challenge!

Note

The 20_Day_Python_package_manager/ directory contains a similar set of functions (arithmetic.py and greet.py) used for the Day 20 lesson. These mirror the mypackage/ code — both demonstrate the same package creation concepts.

Running the Flask Web Application (Day 26)

cd python_for_web
pip install -r requirements.txt
python app.py

 * Serving Flask app "app" (lazy loading)
 * Environment: production
 * Debug mode: on
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

The application provides these pages:

Open http://localhost:5000 in your browser to explore.

Working with the Sample Data Files

The data/ directory contains datasets used in later lessons:

The files/ directory contains smaller examples:

Using the Course in Other Languages

Translations are available in dedicated directories:

Warning

Translation coverage varies significantly. German, Spanish, and Chinese have the most complete translations. Korean and Portuguese cover only a subset of days.

5. Common Tasks

Setting Up a Virtual Environment for the Course

python -m venv venv

Linux/macOS

source venv/bin/activate

Windows

venv\Scripts\activate

Then install any packages you need:

pip install flask beautifulsoup4 requests numpy pandas pymongo

Creating Your Own Module

Following the Day 12 pattern:

1. Create a file named my_math.py:

   def circle_area(radius):
       import math
       return math.pi * radius ** 2
   

2. Import and use it:

   from my_math import circle_area
   print(circle_area(10))  # 314.159...
   

Creating Your Own Package

Following the Day 20 / mypackage pattern:

1. Create a directory with __init__.py:

   my_utils/
   ├── __init__.py
   └── helpers.py
   

2. Add functions to helpers.py
3. Import: from my_utils.helpers import my_function

Practicing String Methods

The Day 4 example file demonstrates every major string method. Run it and compare output:

python 04_Day_Strings/day_4.py

Key methods covered: capitalize(), count(), endswith(), find(), format(), isalnum(), isalpha(), isdecimal(), isdigit(), isidentifier(), islower(), isupper(), isnumeric(), join(), strip(), replace(), split(), title(), swapcase(), startswith().

Practicing List Operations

Run the Day 5 example file for a comprehensive walkthrough of list operations:

python 05_Day_Lists/day_5.py

Operations demonstrated: creating, indexing, negative indexing, slicing, modifying, membership testing (in), append(), insert(), remove(), del, clear(), copy(), concatenation (+), extend(), count(), index(), reverse(), sort().

Scraping a Web Page (Day 22)

The repository includes a sample scraped dataset (22_Day_Web_scraping/scrapped_data.json). To practice web scraping yourself:

pip install beautifulsoup4 requests
python -c "
from bs4 import BeautifulSoup
import requests
url = 'https://example.com'
response = requests.get(url)
soup = BeautifulSoup(response.content, 'html.parser')
print(soup.title.string)
"

Caution

Always check a website's robots.txt and terms of service before scraping. The Day 22 lesson teaches techniques — use them responsibly.

Connecting to MongoDB (Day 27)

You need a MongoDB instance (local or Atlas). After installing pymongo:

pip install pymongo

Follow the Day 27 lesson (27_Day_Python_with_mongodb/27_python_with_mongodb.md) for MongoDB Atlas setup instructions including screenshots.

Building a REST API (Day 29)

The Day 29 lesson walks through creating a Flask-based REST API. The concepts build on the Day 26 Flask introduction.

6. Troubleshooting

Error: ModuleNotFoundError: No module named 'mymodule'

Cause: Running 12_Day_Modules/main.py from the wrong directory. The mymodule.py file must be accessible from the current directory.

Solution:

1. Navigate to the 12_Day_Modules/ directory:

   cd 12_Day_Modules
   python main.py
   

2. Or run from the repo root with the module path:

   python -m 12_Day_Modules.main
   

Prevention: Always cd into the directory containing the script before running it, or ensure mymodule.py is in your Python path.

Error: ModuleNotFoundError: No module named 'flask'

Cause: Flask and its dependencies are not installed.

Solution:

cd python_for_web
pip install -r requirements.txt

Prevention: Create a virtual environment and install dependencies before running the Flask application.

Error: SyntaxError: invalid syntax in Day 1

Cause: Running Python 2 instead of Python 3.

Solution:

python3 01_Day_Introduction/helloworld.py

Prevention: Verify your Python version with python --version — it should show 3.6+.

Error: 404 on Day 22 Ukrainian translation

Cause: Known issue — the Ukrainian Day 2 file has a broken link. (See GitHub issue #769.)

Solution: Use the English version or another available translation.

Content Issues in Exercises

Issue: Several community-reported content errors exist:

• Day 7: Uses "list" where it should say "set" (#823)
• Day 4: Duplicated exercises (#565), incorrect boolean comment in line 159 (#797, #796)
• Day 14: Wrong question text (#808)
• Day 1: Minor code mistake (#807)

Note

These are known upstream issues in the repository. They do not affect the core learning material. Check the GitHub issues page for the latest status and corrections.

Solution: When you encounter a discrepancy, check the lesson's markdown file for the corrected explanation, or consult the GitHub issues.

Flask App: Form Submission Does Not Show Results

Cause: The /post route captures form content but redirects to /result without passing the data. The result.html template renders independently.

Solution: This is a teaching example showing the request/redirect pattern. To make it functional, you would need to pass the analyzed data to the result template (an exercise for the learner).

Package Import Errors with mypackage

Cause: Running from a directory where mypackage/ is not visible.

Solution: Run from the repository root:

python -c "from mypackage.arithmetics import add_numbers; print(add_numbers(1,2,3))"

6

Warning

Python module imports are sensitive to the working directory. Always ensure you are in the correct directory or have configured your PYTHONPATH.

7. FAQ

Q: Do I need prior programming experience to start this course?

No. Day 1 starts from absolute zero — installing Python and printing "Hello World." The course is designed for complete beginners.

Q: Can I skip days or do them out of order?

The course is designed to be sequential, with each day building on prior concepts. However, if you already know basic Python (Days 1–10), you could start from Day 11 (Functions) or later. Days 22–29 are relatively independent topic explorations.

Q: Which Python version should I use?

Python 3.6 or higher. The code examples use f-strings (introduced in 3.6) and other modern Python features. Python 2 is not supported.

Q: How long does each day actually take?

Each day's material typically takes 1–3 hours depending on the topic complexity and how many exercises you complete. Days 25–29 (Pandas, Flask, MongoDB, APIs) tend to be longer.

Q: Are the translations maintained as actively as the English version?

The Chinese, German, and Spanish translations are the most complete (covering Days 2–30). Korean and Portuguese have partial coverage. Translation updates may lag behind the English version.

Q: Why does the Flask app use such old package versions?

The requirements.txt pins Flask 1.1.1 and its dependencies, which were current when the project was created. These versions work correctly for learning purposes. For production use, upgrade to the latest Flask release.

Q: Can I use this material for teaching or workshops?

Check the repository's license for terms. The project is designed as a self-paced learning challenge but the structured daily format works well for classroom settings.

Q: Where are the exercises?

Exercises are at the end of each day's markdown file (e.g., 04_Day_Strings/04_strings.md). They are not in the .py files — the .py files contain the lesson examples.

Q: What is the old_files/ directory?

It contains earlier versions of the README that have been superseded by the per-day directory structure. You can safely ignore them.

Q: How do I report errors or contribute corrections?

Open an issue on the GitHub repository at https://github.com/Asabeneh/30-Days-Of-Python/issues. Several community members have reported content corrections (see Troubleshooting section).