https://mdneuzerling.com Personal blog of David Neuzerling. Data scientist, R engineer, also Python and Julia. Former mathematician, now accidental econometrician. en-us https://mdneuzerling.com/post/painting-skaven-with-oils/ https://mdneuzerling.com/post/painting-skaven-with-oils/ Sun, 18 Jan 2026 00:00:00 GMT My local wargaming club was hosting a _Warhammer: Age of Sigmar_ Spearhead tournament with a twist: if you could paint your entire army between the time the tournament was announced and when the tournament took place (about 2 months), your entry fee was waived. My local wargaming club was hosting...... https://mdneuzerling.com/post/death-taxes-and-tech-workers-hounding-you-to-raise-a-ticket/ https://mdneuzerling.com/post/death-taxes-and-tech-workers-hounding-you-to-raise-a-ticket/ Sun, 04 Jan 2026 00:00:00 GMT Everyone hates ticketing systems. Everyone needs ticketing systems. Ticketing systems are often misused. Everyone hates ticketing systems. Everyone needs ticketing systems. Ticketing systems are often misused. https://mdneuzerling.com/post/wrangling-llm-output-with-langchain/ https://mdneuzerling.com/post/wrangling-llm-output-with-langchain/ Mon, 02 Jun 2025 00:00:00 GMT The toughest prediction any data scientist makes is deciding which tools are worth learning. The explosion of generative AI only makes this harder. My prediction: LangChain is here to stay or, at least, the patterns behind it are. The toughest prediction any data scientist makes is deciding which...... https://mdneuzerling.com/post/why-i-no-longer-code-in-my-free-time/ https://mdneuzerling.com/post/why-i-no-longer-code-in-my-free-time/ Wed, 05 Jun 2024 00:00:00 GMT Those of us who write code are an insecure bunch. Technology moves faster than any one human being can keep up. The threat of falling behind is real and can impact careers and earnings, and that's a terrifying thing. I studied a lot of tech concepts in my free time to try to stay relevant. Those ...... https://mdneuzerling.com/post/plotting-commute-times-with-r-and-google-maps/ https://mdneuzerling.com/post/plotting-commute-times-with-r-and-google-maps/ Fri, 27 Jan 2023 00:00:00 GMT I'm house-hunting, and while I'd love to buy a 5-bedroom house with a pool 10 minutes walk from Flinders Street Station I probably can't afford that. So I need to take a broader look at Melbourne. I'm house-hunting, and while I'd love to buy a 5-bedroom house with a pool 10 minutes walk from Flin...... https://mdneuzerling.com/post/exemplar-a-prototype-r-package-for-data-validation/ https://mdneuzerling.com/post/exemplar-a-prototype-r-package-for-data-validation/ Sun, 20 Mar 2022 00:00:00 GMT I've been playing around with an idea for a new R package. I call it exemplar and here's how it works: I provide an example of what data should look like --- an exemplar. The package gives a function that checks to make sure that any new data looks the same. The generated function checks --- ...... https://mdneuzerling.com/post/my-machine-learning-process-mistakes-included/ https://mdneuzerling.com/post/my-machine-learning-process-mistakes-included/ Mon, 24 Jan 2022 00:00:00 GMT When I train a machine learning model in a blog post, I edit out all the mistakes. I make it seem like I had the perfect data I needed from the very start, and I never add a useless feature. This time, I want to train a model with all the mistakes and fruitless efforts included. When I train a ma...... https://mdneuzerling.com/post/advent-of-code-2021-a-julia-journal-part-2/ https://mdneuzerling.com/post/advent-of-code-2021-a-julia-journal-part-2/ Sun, 19 Dec 2021 00:00:00 GMT Advent of Code is an advent calendar for programming puzzles. I decided to tackle this year's set of 50 puzzles in Julia and journal my experiences along the way. I'm a beginner in Julia so I thought this would help me improve my skills. Advent of Code https://mdneuzerling.com/post/advent-of-code-2021-a-julia-journal-part-1/ https://mdneuzerling.com/post/advent-of-code-2021-a-julia-journal-part-1/ Wed, 15 Dec 2021 00:00:00 GMT Advent of Code is an advent calendar for programming puzzles. I decided to tackle this year's set of 50 puzzles in Julia and journal my experiences along the way. I'm a beginner in Julia so I thought this would help me improve my skills. Advent of Code https://mdneuzerling.com/post/animated-unicode-plots-with-julia/ https://mdneuzerling.com/post/animated-unicode-plots-with-julia/ Thu, 09 Dec 2021 00:00:00 GMT I love Julia's UnicodePlots.jl, a package for making pretty, colourful plots directly in the terminal. While playing around for Advent of Code I wrote a function to animate a sequence of Unicode plots. It's not much, but I couldn't find anything ... https://mdneuzerling.com/post/serverless-on-demand-parametrised-r-markdown-reports-with-aws-lambda/ https://mdneuzerling.com/post/serverless-on-demand-parametrised-r-markdown-reports-with-aws-lambda/ Sun, 21 Nov 2021 00:00:00 GMT I have a URL with a colour parameter, like "<https://example.com/diamonds?colour=H>". When I go to this URL in my browser, an AWS Lambda instance takes that parameter and passes it to rmarkdown::render https://mdneuzerling.com/post/i-tried-to-improve-how-metaflow-converts-r-to-python-and-i-failed/ https://mdneuzerling.com/post/i-tried-to-improve-how-metaflow-converts-r-to-python-and-i-failed/ Sun, 19 Sep 2021 00:00:00 GMT Metaflow is one of my favourite R packages. Actually, it's a Python module, but the R package provides a set of bindings for running R code through Metaflow. Recently I've spent a good amount of effort trying to improve the way that R dat... https://mdneuzerling.com/post/overengineering-an-environment-sensor-with-kubernetes-and-prometheus/ https://mdneuzerling.com/post/overengineering-an-environment-sensor-with-kubernetes-and-prometheus/ Wed, 04 Aug 2021 00:00:00 GMT One of the joys of keeping a personal blog is that I don't have to justify a post. If I want to hook up 4 Raspberry Pis into a Kubernetes cluster just to monitor the humidity of my living room, then I can. One of the joys of keeping a personal blog is that I don't have to justify a post. If I wan...... https://mdneuzerling.com/post/identifying-custom-australian-licence-plates/ https://mdneuzerling.com/post/identifying-custom-australian-licence-plates/ Sun, 18 Jul 2021 00:00:00 GMT In case this saves anyone some time, here's a quick bit of regex and Python code for identifying if a given licence plate is standard or custom (personalised) in a given state. In case this saves anyone some time, here's a quick bit of regex and Python code for identifying if a given licence plat...... https://mdneuzerling.com/post/everybody-loves-raymond-running-animal-crossing-villagers-through-the-google-vision-api/ https://mdneuzerling.com/post/everybody-loves-raymond-running-animal-crossing-villagers-through-the-google-vision-api/ Sun, 06 Jun 2021 00:00:00 GMT The Animal Crossing Portal is a fan site that runs a monthly poll on favourite villagers. They keep historical data in publicly available Google Sheets, which makes a data scientist like me very happy. The Animal Crossing Portal https://mdneuzerling.com/post/some-dockerfiles-for-building-r-package-binaries/ https://mdneuzerling.com/post/some-dockerfiles-for-building-r-package-binaries/ Mon, 19 Apr 2021 00:00:00 GMT I went down a strange path recently, trying to compile binaries of R packages for Linux. I'm not sure why --- this area is pretty much covered by the RStudio Package Manager. I'll leave my Dockerfiles here in case they're of any use to a future wayw... https://mdneuzerling.com/post/machine-learning-workflows-with-julia/ https://mdneuzerling.com/post/machine-learning-workflows-with-julia/ Mon, 01 Mar 2021 00:00:00 GMT I have a simple machine learning workflow that I recreate whenever I'm testing something new. I take some interesting data and a target, throw in some pre-processing, tune hyperparameters with cross-validation, and train a random forest. It's all the basic ingredients for a machine learning model...... https://mdneuzerling.com/post/using-metaflow-to-make-model-tuning-less-painful/ https://mdneuzerling.com/post/using-metaflow-to-make-model-tuning-less-painful/ Wed, 27 Jan 2021 00:00:00 GMT I have a machine learning model that takes some time to train. Data pre-processing and model fitting can take 15--20 minutes. That's not so bad, but I also want to tune my model to make sure I'm using the best hyper-parameters. With 16 different combinations of hyperparameters and 5-fold cross-va...... https://mdneuzerling.com/post/r-on-aws-lambda-with-containers/ https://mdneuzerling.com/post/r-on-aws-lambda-with-containers/ Sun, 06 Dec 2020 00:00:00 GMT AWS has announced support for container images for their serverless computing platform Lambda. AWS doesn't provide an R runtime for Lambda, and this was the excuse I needed to finally try to make one. [AWS has annou... https://mdneuzerling.com/post/determining-system-dependencies-for-r-projects/ https://mdneuzerling.com/post/determining-system-dependencies-for-r-projects/ Sun, 25 Oct 2020 00:00:00 GMT Locking down R package dependencies and versions is a solved problem, thanks to the easy-to-use renv package. System dependencies --- those Linux packages that need to be installed to make certain R packages work --- are a bit harder to manage. Locking down R package dependencies and versions i......