About Geir Arne Hjelle

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After years pondering the question Where are we? I now work with data science and machine learning in Oslo, Norway.

Earlier, I’ve played with everything from Basic, Awk, Java and C to Assembly. Now, I’m lucky enough to do most of my coding in Python. Other favorites include board games, hammocks, square roots and skiing (preferably up-hill). In my spare time I also have the pleasure of teaching kids to code.

Tutorials by Geir Arne:

Python News Roundup: February 2025
Build a Quiz Application With Python
Python and TOML: New Best Friends
Python's pathlib Module: Taming the File System
The Walrus Operator: Python's Assignment Expressions
Primer on Python Decorators
Python Timer Functions: Three Ways to Monitor Your Code
Python range(): Represent Numerical Ranges
Python News Roundup: October 2024
Python 3.13: Cool New Features for You to Try
Python 3.13 Preview: A Modern REPL
Python News Roundup: July 2024
Python News: What's New From March 2024
Python News: What's New From October 2023
Python 3.12: Cool New Features for You to Try
Python 3.12 Preview: Static Typing Improvements
Why Are Membership Tests So Fast for range() in Python?
Python News: What's New From May 2023
How to Get Normally Distributed Random Numbers With NumPy
Build a Wordle Clone With Python and Rich
Learn From 2022's Most Popular Python Tutorials and Courses
Advent of Code: Solving Your Puzzles With Python
Should You Update to the Latest Python Bugfix Version?
Python 3.11: Cool New Features for You to Try
Minimax in Python: Learn How to Lose the Game of Nim
How Can You Install a Pre-Release Version of Python?
Python 3.11 Preview: TOML and tomllib
How to Publish an Open-Source Python Package to PyPI
Python News: What's New From April 2022
Python 3.11 Preview: Task and Exception Groups
Python 3.11 Preview: Even Better Error Messages
Python News: What's New From December 2021
Python News: What's New From October 2021
Python 3.10: Cool New Features for You to Try
Python 3.9: Cool New Features for You to Try
Python import: Advanced Techniques and Tips
Run Python Versions in Docker: How to Try the Latest Python Release
Python 3.8: Cool New Features for You to Try
Python Type Checking (Guide)
Python 3.7: Cool New Features for You to Try
Data Classes in Python 3.7+ (Guide)

Tutorials Contributed to by Geir Arne:

Python Scope and the LEGB Rule: Resolving Names in Your Code
How to Debug Common Python Errors
What Is Python's __init__.py For?
Use TorchAudio to Prepare Audio Data for Deep Learning
Python enumerate(): Simplify Loops That Need Counters
How to Find an Absolute Value in Python
How Can You Structure Your Python Script?
Control Flow Structures in Python
marimo: A Reactive, Reproducible Notebook
How to Group Data Using Polars .group_by()
How to Get the Most Out of PyCon US
How to Use Loguru for Simpler Python Logging
Modern Web Automation With Python and Selenium
How to Copy Objects in Python: Shallow vs Deep Copy Explained
How to Exit Loops Early With the Python Break Keyword
Using Python's .__dict__ to Work With Attributes
Python News Roundup: April 2025
How to Strip Characters From a Python String
Python's Bytearray: A Mutable Sequence of Bytes
Introducing DuckDB
Python Code Quality: Best Practices and Tools
LangGraph: Build Stateful AI Agents in Python
Python's Instance, Class, and Static Methods Demystified
Python Textual: Build Beautiful UIs in the Terminal
Python News Roundup: March 2025
Bytes Objects: Handling Binary Data in Python
Python while Loops: Repeating Tasks Conditionally
How to Work With Polars LazyFrames
How to Use sorted() and .sort() in Python
How to Manage Python Projects With pyproject.toml
Python Keywords: An Introduction
How to Join Strings in Python
How to Split a String in Python
Python for Loops: The Pythonic Way
Build a Dice-Rolling Application With Python
Top Python Game Engines
Develop Data Visualization Interfaces in Python With Dash
Providing Multiple Constructors in Your Python Classes
Build a Tic-Tac-Toe Game With Python and Tkinter
Natural Language Processing With spaCy in Python
Python & APIs: A Winning Combo for Reading Public Data
A Guide to Modern Python String Formatting Tools
Split Your Dataset With scikit-learn's train_test_split()
How to Split a Python List or Iterable Into Chunks
Python's Mutable vs Immutable Types: What's the Difference?
Python's "in" and "not in" Operators: Check for Membership
Python Folium: Create Web Maps From Your Data
Python's zipfile: Manipulate Your ZIP Files Efficiently
Lists vs Tuples in Python
How to Download Files From URLs With Python
Python's raise: Effectively Raising Exceptions in Your Code
Executing Python Scripts With a Shebang
How to Flush the Output of the Python Print Function
How to Deal With Missing Data in Polars
Getters and Setters: Manage Attributes in Python
Python Class Constructors: Control Your Object Instantiation
Create and Modify PDF Files in Python
pandas GroupBy: Your Guide to Grouping Data in Python
Python Constants: Improve Your Code's Maintainability
Python's min() and max(): Find Smallest and Largest Values
The subprocess Module: Wrapping Programs With Python
Understanding the Python Mock Object Library
Get Started With Django: Build a Portfolio App
NumPy's max() and maximum(): Find Extreme Values in Arrays
How to Replace a String in Python
Primer on Jinja Templating
Variables in Python: Usage and Best Practices
How to Get a List of All Files in a Directory With Python
Python's assert: Debug and Test Your Code Like a Pro
How to Write Beautiful Python Code With PEP 8
Inheritance and Composition: A Python OOP Guide
Python's urllib.request for HTTP Requests
Operators and Expressions in Python
HTML and CSS for Python Developers
Image Processing With the Python Pillow Library
Iterators and Iterables in Python: Run Efficient Iterations
Learn From 2024's Most Popular Python Tutorials and Courses
How to Remove Items From Lists in Python
How to Flatten a List of Lists in Python
Working With JSON Data in Python
Using Python's pip to Manage Your Projects' Dependencies
Strings and Character Data in Python
A Practical Introduction to Web Scraping in Python
Basic Data Types in Python: A Quick Exploration
Get Started With Django User Management
Dictionaries in Python
Object-Oriented Programming (OOP) in Python
Build Enumerations of Constants With Python's Enum
Dependency Management With Python Poetry
Python Classes: The Power of Object-Oriented Programming
Python's property(): Add Managed Attributes to Your Classes
Sorting a Python Dictionary: Values, Keys, and More
Build Command-Line Interfaces With Python's argparse
YAML: The Missing Battery in Python
Python Set Comprehensions: How and When to Use Them
Python News Roundup: December 2024
How to Run Your Python Scripts and Code
Effective Python Testing With pytest
Asynchronous Tasks With Django and Celery
Using and Creating Global Variables in Your Python Functions
Python GUI Programming: Your Tkinter Tutorial
Socket Programming in Python (Guide)
How to Round Numbers in Python
When to Use a List Comprehension in Python
Linear Regression in Python
Expression vs Statement in Python: What's the Difference?
Basic Input and Output in Python
How to Check if a Python String Contains a Substring
Python String Formatting: Available Tools and Their Features
Python Exceptions: An Introduction
Beautiful Soup: Build a Web Scraper With Python
Python Virtual Environments: A Primer
Logging in Python
What Does if __name__ == "__main__" Do in Python?
Python's F-String for String Interpolation and Formatting
Continuous Integration and Deployment for Python With GitHub Actions
Speed Up Your Python Program With Concurrency
Efficient String Concatenation in Python
How to Iterate Through a Dictionary in Python
NumPy Practical Examples: Useful Techniques
Interacting With Python
Using the Python zip() Function for Parallel Iteration
Using the len() Function in Python
Python Dictionary Comprehensions: How and When to Use Them
Python News Roundup: November 2024
How to Reset a pandas DataFrame Index
The Python Square Root Function
Python Closures: Common Use Cases and Examples
Python Thread Safety: Using a Lock and Other Techniques
Structural Pattern Matching in Python
Syntactic Sugar: Why Python Is Sweet and Pythonic
Build a Contact Book App With Python, Textual, and SQLite
Python 3.13 Preview: Free Threading and a JIT Compiler
How to Use Conditional Expressions With NumPy where()
Python News Roundup: September 2024
Generate Images With DALL·E and the OpenAI API
Web Scraping With Scrapy and MongoDB
Python News Roundup: August 2024
Asynchronous Iterators and Iterables in Python
Functional Programming in Python: When and How to Use It
How to Write an Installable Django App
Hugging Face Transformers: Leverage Open-Source AI in Python
Python Protocols: Leveraging Structural Subtyping
How Do You Choose Python Function Names?
Python's Built-in Functions: A Complete Exploration
Creating Great README Files for Your Python Projects
Build a Guitar Synthesizer: Play Musical Tablature in Python
Ruff: A Modern Python Linter for Error-Free and Maintainable Code
Python Mappings: A Comprehensive Guide
Python News: What's New From May 2024
String Interpolation in Python: Exploring Available Tools
What Are CRUD Operations?
How to Create Pivot Tables With pandas
The Python calendar Module: Create Calendars With Python
Python's Built-in Exceptions: A Walkthrough With Examples
What Is the __pycache__ Folder in Python?
PyTorch vs TensorFlow for Your Python Deep Learning Project
Python News: What's New From April 2024
Python Sequences: A Comprehensive Guide
Python's unittest: Writing Unit Tests for Your Code
What's Lazy Evaluation in Python?
Write Unit Tests for Your Python Code With ChatGPT
How to Format Floats Within F-Strings in Python
Build a Blog Using Django, GraphQL, and Vue
Pydantic: Simplifying Data Validation in Python
Install and Execute Python Applications Using pipx
Reading and Writing WAV Files in Python
Prompt Engineering: A Practical Example
Build a Python Turtle Game: Space Invaders Clone
Model-View-Controller (MVC) in Python Web Apps: Explained With Lego
Visualizing Data in Python With Seaborn
Python News: What's New From February 2024
Build an LLM RAG Chatbot With LangChain
Python's __all__: Packages, Modules, and Wildcard Imports
Python's Requests Library (Guide)
Duck Typing in Python: Writing Flexible and Decoupled Code
How to Read User Input From the Keyboard in Python
BNF Notation: Dive Deeper Into Python's Grammar
Python News: What's New From January 2024
Python's Format Mini-Language for Tidy Strings
What Are Python Raw Strings?
Using Python for Data Analysis
Learn From 2023's Most Popular Python Tutorials and Courses
Python's Magic Methods: Leverage Their Power in Your Classes
Python's Array: Working With Numeric Data Efficiently
Add Logging and Notification Messages to Flask Web Projects
Enhance Your Flask Web Project With a Database
Build a Scalable Flask Web Project From Scratch
Python News: What's New From November 2023
Build a Hangman Game With Python and PySimpleGUI
Serialize Your Data With Python
Single and Double Underscores in Python Names
The Python Rich Package: Unleash the Power of Console Text
Build Conway's Game of Life With Python
How to Render Markdown in a Django Application
Embeddings and Vector Databases With ChromaDB
JupyterLab for an Enhanced Notebook Experience
Document Your Python Code and Projects With ChatGPT
Build a Hangman Game for the Command Line in Python
How to Use Type Hints for Multiple Return Types in Python
Boost Your Coding Productivity With Ptpython
Build a Blog From Scratch With Django
How to Sort Unicode Strings Alphabetically in Python
Python News: What's New From September 2023
Python's tuple Data Type: A Deep Dive With Examples
Python 3.12 Preview: Subinterpreters
How to Catch Multiple Exceptions in Python
Bypassing the GIL for Parallel Processing in Python
Generate Beautiful QR Codes With Python
Python News: What's New From August 2023
Click and Python: Build Extensible and Composable CLI Apps
Build a Code Image Generator With Python
Python Polars: A Lightning-Fast DataFrame Library
What Are Python Asterisk and Slash Special Parameters For?
Python News: What's New From July 2023
Working With the Python operator Module
Python 3.12 Preview: More Intuitive and Consistent F-Strings
Profiling in Python: How to Find Performance Bottlenecks
Python 3.12 Preview: Support For the Linux perf Profiler
Python's Self Type: How to Annotate Methods That Return self
How to Make Engaging Programming Videos
What Exactly Is the Zen of Python?
Using the NumPy Random Number Generator
Choosing the Best Coding Font for Programming
Python's .__call__() Method: Creating Callable Instances
How to Launch an HTTP Server in One Line of Python Code
Use ChatGPT to Learn Python Programming
Python News: What's New From April 2023
Build Robust Continuous Integration With Docker and Friends
Build Your Own Face Recognition Tool With Python
Python 3.12 Preview: Ever Better Error Messages
Python's del: Remove References From Scopes and Containers
Build a Maze Solver in Python Using Graphs
How to Read Python Input as Integers
When Should You Use .__repr__() vs .__str__() in Python?
How to Evaluate the Quality of Python Packages
Python News: What's New From February 2023
What's a Python Namespace Package, and What's It For?
Using NumPy reshape() to Change the Shape of an Array
The Terminal: First Steps and Useful Commands
Python News: What's New From January 2023
Build a JavaScript Front End for a Flask API
How to Iterate Over Rows in pandas, and Why You Shouldn't
The Python Standard REPL: Try Out Code and Ideas Quickly
Linear Algebra in Python: Matrix Inverses and Least Squares
Working With Linear Systems in Python With scipy.linalg
Python's Assignment Operator: Write Robust Assignments
Discover bpython: A Python REPL With IDE-Like Features
How to Get and Use the Current Time in Python
Python News: What's New From November 2022
Microsoft Power BI and Python: Two Superpowers Combined
Python REST APIs With Flask, Connexion, and SQLAlchemy – Part 3
Python REST APIs With Flask, Connexion, and SQLAlchemy – Part 2
Python REST APIs With Flask, Connexion, and SQLAlchemy – Part 1
Python News: What's New From October 2022
Python's doctest: Document and Test Your Code at Once
How to Get the First Match From a Python List or Iterable
Build a Tic-Tac-Toe Game Engine With an AI Player in Python
ChatterBot: Build a Chatbot With Python
Python News: What's New From September 2022
Custom Python Strings: Inheriting From str vs UserString
How to Add Python to PATH
When Do You Use an Ellipsis in Python?
Custom Python Lists: Inheriting From list vs UserList
Python News: What's New From August 2022
Python and PyQt: Building a GUI Desktop Calculator
Python's exec(): Execute Dynamically Generated Code
GitHub Copilot: Fly With Python at the Speed of Thought
Python News: What's New From July 2022
Your Python Coding Environment on Windows: Setup Guide
Custom Python Dictionaries: Inheriting From dict vs UserDict
Build a Flashcards App With Django
Python News: What's New From June 2022
Python Stacks, Queues, and Priority Queues in Practice
How Can You Emulate Do-While Loops in Python?
Build Your Python Project Documentation With MkDocs
A First Look at PyScript: Python in the Web Browser
LBYL vs EAFP: Preventing or Handling Errors in Python
Python News: What's New From May 2022
Level Up Your Skills With the Real Python Slack Community
Build a URL Shortener With FastAPI and Python
Real Python at PyCon US 2022
Why Is It Important to Close Files in Python?
Combining Data in pandas With merge(), .join(), and concat()
Python News: What's New From March 2022
Build a Site Connectivity Checker in Python
Pagination for a User-Friendly Django App
Build a Hash Table in Python With TDD
Python News: What's New From February 2022
Manage Your To-Do Lists Using Python and Django
Python's all(): Check Your Iterables for Truthiness
Python News: What's New From January 2022
Draw the Mandelbrot Set in Python
Raining Outside? Build a Weather CLI App With Python
Modulo String Formatting in Python
Build and Submit HTML Forms With Django – Part 4
Build and Handle POST Requests in Django – Part 3
Build a Django Front End With Bulma – Part 2
Build a Social Network With Django – Part 1
Python Zip Imports: Distribute Modules and Packages Quickly
Java vs Python: Basic Python for Java Developers
Securely Deploy a Django App With Gunicorn, Nginx, & HTTPS
Advanced Visual Studio Code for Python Developers
Using the "not" Boolean Operator in Python
A Roadmap to XML Parsers in Python
Representing Rational Numbers With Python Fractions
A Python Guide to the Fibonacci Sequence
Python and REST APIs: Interacting With Web Services
Python's collections: A Buffet of Specialized Data Types
Using FastAPI to Build Python Web APIs
What Can I Do With Python?
Simplify Complex Numbers With Python
Python Practice Problems: Parsing CSV Files
Embedded Python: Build a Game on the BBC micro:bit
Natural Language Processing With Python's NLTK Package
Build a Platform Game in Python With Arcade
Deploying a Python Flask Example Application Using Heroku
Build a Python Directory Tree Generator for the Command Line
The k-Nearest Neighbors (kNN) Algorithm in Python
OrderedDict vs dict in Python: The Right Tool for the Job
Build an Asteroids Game With Python and Pygame
Python AI: How to Build a Neural Network & Make Predictions
pandas Sort: Your Guide to Sorting Data in Python
Python Microservices With gRPC
Python Inner Functions: What Are They Good For?
Qt Designer and Python: Build Your GUI Applications Faster
Python Web Applications: Deploy Your Script as a Flask App
Stochastic Gradient Descent Algorithm With Python and NumPy
How to Use Python: Your First Steps
Make Your First Python Game: Rock, Paper, Scissors!
Sentiment Analysis: First Steps With Python's NLTK Library
NumPy Tutorial: Your First Steps Into Data Science in Python
Python's .append(): Add Items to Your Lists in Place
Python and MySQL Database: A Practical Introduction
Use PyQt's QThread to Prevent Freezing GUIs
The pass Statement: How to Do Nothing in Python
What Is Data Engineering and Is It Right for You?
Bitwise Operators in Python
Handling SQL Databases With PyQt: The Basics
np.linspace(): Create Evenly or Non-Evenly Spaced Arrays
PyQt Layouts: Create Professional-Looking GUI Applications
Python and PyQt: Creating Menus, Toolbars, and Status Bars
PyPy: Faster Python With Minimal Effort
Caching in Python Using the LRU Cache Strategy
Fourier Transforms With scipy.fft: Python Signal Processing
Get Started With Django Part 3: Django View Authorization
Python Modulo in Practice: How to Use the % Operator
Python Booleans: Use Truth Values in Your Code
Data Management With Python, SQLite, and SQLAlchemy
Using ggplot in Python: Visualizing Data With plotnine
Python's map(): Processing Iterables Without a Loop
The Python return Statement: Usage and Best Practices
Python Practice Problems: Get Ready for Your Next Interview
Plot With pandas: Python Data Visualization for Beginners
Python mmap: Improved File I/O With Memory Mapping
Data Version Control With Python and DVC
Pass by Reference in Python: Background and Best Practices
Customize the Django Admin With Python
Generative Adversarial Networks: Build Your First Models
Python Packages: Five Real Python Favorites
K-Means Clustering in Python: A Practical Guide
pandas Project: Make a Gradebook With Python & pandas
Learn IP Address Concepts With Python's ipaddress Module
Python's reduce(): From Functional to Pythonic Style
The Python heapq Module: Using Heaps and Priority Queues
Hands-On Linear Programming: Optimization With Python
PySimpleGUI: The Simple Way to Create a GUI With Python
SettingWithCopyWarning in pandas: Views vs Copies
Build Physical Projects With Python on the Raspberry Pi
Python vs JavaScript for Pythonistas
Python eval(): Evaluate Expressions Dynamically
How to Move a Django Model to Another App
Using Python datetime to Work With Dates and Times
The Python pickle Module: How to Persist Objects in Python
The pandas DataFrame: Make Working With Data Delightful
Sorting Algorithms in Python
How to Provide Test Fixtures for Django Models in Pytest
How to Make an Instagram Bot With Python and InstaPy
Linked Lists in Python: An Introduction
How to Use any() in Python
SimPy: Simulating Real-World Processes With Python
The Python math Module: Everything You Need to Know
How to Do a Binary Search in Python
Using the Python defaultdict Type for Handling Missing Keys
Alexa Python Development: Build and Deploy an Alexa Skill
Python Bindings: Calling C or C++ From Python
The Beginner's Guide to Python Turtle
Introduction to Python SQL Libraries
Null in Python: Understanding Python's NoneType Object
Implementing an Interface in Python
Python Command-Line Arguments
Use a Flask Blueprint to Architect Your Applications
Python != Is Not is not: Comparing Objects in Python
Scientific Python: Using SciPy for Optimization
Arcade: A Primer on the Python Game Framework
Logistic Regression in Python
Exploring HTTPS With Python
Using pandas and Python to Explore Your Dataset
NumPy, SciPy, and pandas: Correlation With Python
Python Statistics Fundamentals: How to Describe Your Data
Data Engineer Interview Questions With Python
pandas: How to Read and Write Files
Python Descriptors: An Introduction
Invalid Syntax in Python: Common Reasons for SyntaxError
Build a Mobile Application With the Kivy Python Framework
Arduino With Python: How to Get Started
Python sleep(): How to Add Time Delays to Your Code
Emacs: The Best Python Editor?
Preventing SQL Injection Attacks With Python
How to Use Generators and yield in Python
Getting Started With Async Features in Python
PyGame: A Primer on Game Programming in Python
MATLAB vs Python: Why and How to Make the Switch
Python args and kwargs: Demystified
Real Python at PyCon US 2019
Three Ways of Storing and Accessing Lots of Images in Python
How to Stand Out in a Python Coding Interview
Refactoring Python Applications for Simplicity
Supercharge Your Classes With Python super()
The Factory Method Pattern and Its Implementation in Python
Working With Files in Python
Thonny: The Beginner-Friendly Python Editor
Interactive Data Visualization in Python With Bokeh
Getting Started With Testing in Python
Python Program Lexical Structure
Python pandas: Tricks & Features You May Not Know
Reading and Writing CSV Files in Python
Generating Random Data in Python (Guide)
Operator and Function Overloading in Custom Python Classes
Python IDEs and Code Editors (Guide)

Courses Contributed to by Geir Arne:

Python Project: Build a Word Count Command-Line App
Working With TOML and Python
What's New in Python 3.13
Advanced Python import Techniques
Advent of Code: Solving Puzzles With Python
What's New in Python 3.12
Create a Python Wordle Clone With Rich
Publishing Python Packages to PyPI
Using the Terminal on Linux
Using Python's pathlib Module
Everyday Project Packaging With pyproject.toml
Cool New Features in Python 3.11
Python Assignment Expressions and Using the Walrus Operator
Cool New Features in Python 3.10
Using Data Classes in Python
Cool New Features in Python 3.9
Cool New Features in Python 3.8
Python Type Checking
The Python range() Function
How to Publish Your Own Python Package to PyPI
Python Decorators 101

Podcast Episodes Featuring Geir Arne:

The Real Python Podcast – Episode #223: Exploring the New Features of Python 3.13
The Real Python Podcast – Episode #175: Exploring the New Features of Python 3.12
The Real Python Podcast – Episode #138: 2022 Real Python Tutorial & Video Course Wrap Up
The Real Python Podcast – Episode #131: Exploring the New Features of Python 3.11
The Real Python Podcast – Episode #107: Type-Safe ORM With Prisma Client & Real Python at PyCon US 2022
The Real Python Podcast – Episode #89: Solving Advent of Code Puzzles With Python
The Real Python Podcast – Episode #81: Exploring the New Features of Python 3.10
The Real Python Podcast – Episode #30: Exploring the New Features of Python 3.9
The Real Python Podcast – Episode #1: Python Decorators and Writing for Real Python