Paddy Mullen
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Paddy Mullen
@paddymullen.bsky.social
89 followers 550 following 120 posts
Boston/Newport. Python/PyData/Jupyter dev. Building the Buckaroo widgetto enhance the DataFrame viewing experience in Jupyter https://github.com/paddymul/buckaroo
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Next fun polars extension I’m going to write - Crash_on_demand. It will crash whenever called or at specified conditions. Why? Well polars and analytical workflows fail occasionally, I’m writing a resilient workflow engine, and I want deterministic crashes for testing.
October 15, 2025 at 4:24 PM
I wrote my first rust code and polars extension - pl_series_hash. It runs xx_hash over an entire series to get a single hash u64. Works on most all Polars data types including nested structs, it's fast. WIll be very useful for caching summary stats. github.com/paddymul/pl_...
GitHub - paddymul/pl_series_hash: a polars plugin to performantly cache series
a polars plugin to performantly cache series. Contribute to paddymul/pl_series_hash development by creating an account on GitHub.
github.com
October 5, 2025 at 4:26 PM
Looking at the data with Buckaroo
- My talk from PyData Boston is now up on youtube.
www.youtube.com/watch?v=Htah...
Paddy Mullen - Looking at the Data with Buckaroo (PyData Boston 2025)
YouTube video by PyData
www.youtube.com
August 21, 2025 at 2:18 PM
After a bunch of work with prot, I got my custom find-grep script plumbed into emacs.

It searches a python project for matches in preferred files first (not site-packages, node_modules, py, js, tx extensions preferred). Then it runs a much more comprehensive search of those excluded directories
August 11, 2025 at 9:09 PM
Life pro tip. Next time you have to assemble IKEA furniture, buy yourself a 4mm hex t-handle. and a 4mm wera (or wiha) allen key. So much easier. www.kleintools.com/catalog/t-ha...
4 mm Hex Key, Journeyman™ T-Handle, 6-Inch - JTH6M4 | Klein Tools
Klein hex-keys are the tools professionals cannot afford to be without. Heat-treated and tempered for superior strength and durability. Klein hex-keys are designed for a precise fit in sockets, preven...
www.kleintools.com
August 11, 2025 at 12:58 PM
UGH, I thought I was so slick. I had a nice function that used polars to convert a csv to parquet with enum columns for sparsely populated columns. I thought it saved about 30% on a 700 meg parquet file (10G csv). Then I dug some more and found out that I was encoding all possible sparse value
August 9, 2025 at 10:02 PM
Some content is on Youtube and few other places (heavy equipment, dirt bikes...). But I realized generally I have been searching youtube for more topics because I trust the results more than SEO spam... And this is after I switched to ddg. Obviously there are shills on yt, but beats listicles.
August 1, 2025 at 10:17 PM
There is some good stuff on facebook. Fun post from the mainframers group about an IBM Sytem 370 card for the IBM PS/2. www.facebook.com/share/p/17tx...
Some people may ask, "What is a mainframe?". Well, the answer varies, everything from the multi-ton beasts, to the smaller versions. How small? May I present one of the mainframes I used to operate/administer, an IBM P/370. That's a complete IBM S/370 processor, including a full 16M of memory, on a single MCA card, which fit into a PS/2 model 95 system, and which ran VM/SP 5. Once, just for grins and giggles, I IPLed a second level VM system. Then, for more grins and giggles, I IPLed a third level VM system. But, it drove me crazy trying to remember which prompt to use for which system. Still, it demonstrated how thorough of an architecture implementation the card was. https://en.wikipedia.org/.../PC-based_IBM_mainframe... It was great having my own personal mainframe, which I used for product development and testing. It allowed me to do test installs of software on a real mainframe. Anyway, since some of y'all are posting really great pictures of machine rooms and big mainframes, I thought I'd offer a glimpse of what may be one of the smallest mainframes. 🙂 Oh, yeah, there was a follow-on product, the P/390, which was a S/390 system on a card. I lusted after one for many years, but was never able to justify it. And, there were a couple of proceeding products, the 7437, which was a full S/370 in a box about the size of a PS/2 model 95. There was also the XT/370, which was a PC/XT, with a card-set in it which was a partial implementation of the S/370 instruction set (one of which I happen to personally own). I was the team leader for the 7437 project and designed most of the CPU. It used an IBM bit slice (similar to the AMD 2900), and an IBM chip called FLAINE which implemented the floating point instructions. The rest of the CPU was built using mostly 7400F and 7400LS chips. The CPU had a writeable control store of 8K words of 96 bits each. Initially, we implemented dynamic address translation in 7400 logic, but then one of our engineers, Tak Ng, designed a CMOS chip to do the translation, and that went into the product-level release. The chip replaced a whole card worth of 7400 logic. The 7437 consisted of 6 cards, each approximately 9x12". The cards were the Instruction Unit, Execution Unit, Control Store, PS2 Interface and two 8 MB memory cards. Below is a photo of the writeable control store card. It's the only piece of hardware I still have. The XT/370 was based on a Motorola 68000 that IBM paid Motorola to modify to execute 370 instructions. The chip only could run CMS and not CP as it did not support supervisor state. Instead CP functions were provided by X86 code running on the PC. The P/370 and the P/390 chips were also designed by Tak Ng. The 7437, P/370 and P/390 were all done in Bill Beausoleil's IBM Fellow department by a team of 6 to 10 engineers and programmers. Bill wanted IBM to sell the 7437 for about $5,000. But that would have seriously broken IBM's pricing model vs the cost/performance of traditional mainframes like the 4341 which sold for something like $100,000. VM wanted to charge something like $100K for a 7437 license, Upper level executives were frightened that customers would buy a slew of 7437s instead of a 3090, costing IBM millions in profit. They swore that they would never let the 7437 go out the door if it meant losing the sale of even one 3090. In the end, they severely restricted who could buy a 7437 by bundling it with a 5080 graphics workstation and pricing it at $50,000.
June 17, 2025 at 12:59 PM
On the toughest most annoying problems I need to try to put in a half hour to an hour a day, and let ideas percolate. But actually do that work, it's much more effective than hours of grinding. I'm thinking about devops stuff especially
June 13, 2025 at 5:40 PM
You hear those stories about how garbage collection on lisp machines in the 80s didn't really work and engineers just restarted the machine once a day. Then I realized I do the same thing with firefox/chrome. Need to upgrade to a 32+GB laptop
June 13, 2025 at 4:28 PM
I have started heavily typing my python code. I’m late to the party on this one, I know, but here are some thoughts.

I was prompted by finally getting eglot mode working with basedpyright in eMacs.
June 11, 2025 at 2:53 PM
Hit a snag with the multi-index refactoring. The short of it is that dataframe serialization is really tricky and relying on assumption and default behavors will bite you, always
June 9, 2025 at 2:20 PM
And I now have pandas MultiIndex columns rendering nested locally.
Image showing buckaroo in marimo rendering a dataframe with multi index columns. the headers are nested
June 8, 2025 at 4:04 PM
Bahhhh. Traitlets doesn't like typing. I'm trying to add types to my project, and I have written most of them, but my project heavily uses traits, and they don't get along with python typing
June 8, 2025 at 1:14 PM
I'm kneedeep in adding proper multi index-column support to Buckaroo. MultiIndexes are kind of a corner case of pandas, super powerful but often forgotten. Many tables don't display them properly because they are tricky. They don't serialize to JSON natively. #python #pandas #datascience #pydata
Mockup of multi indexes in storybook for buckaroo. This shows the nested column headers
June 7, 2025 at 4:27 PM
So, apparently SRAM NX 1x12 isn't a good fit on a 20 inch wheel. The RD hits the tire in the 3rd largest gear. #cargobike #bike
Image showing limited clearance between the derailleur and tire. Here the derailleur is in the 3rd or 4th largest gear Clearance between the derailleur and the ground when the derailleur is at it's most downward extended position. Riding the cargo bike on grass. Note the 20 inch rear wheel and 26 inch front wheel. A coastal scene is in the background.
June 5, 2025 at 5:09 PM
I have been playing with beartype. It's a library for fast runtime type verification in python. The maintainer is one of the most entertaining writers I have seen. Period. His response to my feature request/(trying to understand his library) has brought so much joy. github.com/beartype/bea...
[Feature Request] New `BeartypeInferHintConf(infer_hint_dict_kind)` configuration option for fine-grained dictionary type hint inference 🧘 · Issue #529 · beartype/beartype
Is it within the scope of beartype to do the following: def takes_a_dict(foo): temp = foo['a'] + len(foo['some_str']) b = "asdf" return dict(temp=temp, b=b) infer_hint(takes_a_dict) --- collections...
github.com
June 1, 2025 at 7:38 PM
#Cargobike wheel build complete. Excited to try this tomorrow
May 17, 2025 at 12:54 AM
I made a new Buckaroo general overview video. youtu.be/t-wk24F1G3s (6m50s). It demonstrates the main features of the Buckaroo table UI. #python #jupyter
Buckaroo full tour
YouTube video by Paddy Mullen
youtu.be
May 12, 2025 at 8:43 PM
Buckaroo Autocleaning released. Dataframe columns are inspected and cleaning operations are suggested. Different strategies can be interactively cycled through. All of this is extensible. Because it uses heuristics and not LLMs, everything is local and fast. www.youtube.com/watch?v=A-GK...
Buckaroo Autocleaning in depth
YouTube video by Paddy Mullen
www.youtube.com
May 11, 2025 at 12:35 PM
Just had my first emacs coaching session with prot. I have used emacs for years and I'm at a local optimum. So excited to have someone to work through and intentionally get better at the program I live in. protesilaos.com Do any other programmers have coaches?
Contact me
Information for contacting Protesilaos Stavrou.
protesilaos.com
May 5, 2025 at 4:32 PM
There is cad vs cad esports. If you are a UI/UX designer, pay attention to how efficient experienced cad users are. Even better,

This videos shows a competition measuring the mass of a complex design. Open to any program (Solidworks, NX, Catia)
www.youtube.com/live/C1CqIcf...
CAD vs CAD esports Tournament - 2025 SPRING OPEN - 1 PM East Coast, USA
YouTube video by Too Tall Toby
www.youtube.com
May 4, 2025 at 12:25 PM
Reposted by Paddy Mullen
bobbicodes.bsky.social
I've been writing a #Clojure compiler in JavaScript, and I just benchmarked it with my NES audio emulator and it clocked at over 60fps which means it's fast enough to run in real time.

Compiler source: codeberg.org/bobbicodes/n...
Emulator: codeberg.org/bobbicodes/n...
nomad-vite
ES6 Lisp interpreter
codeberg.org
April 30, 2025 at 4:52 PM
Autocleaning for buckaroo is really shaping up. This is the JLisp code editor showing operations that were added by an auto-cleaning strategy in purple. Multiple strategies are available and they can be cycled through quickly to try different approaches. #buildinpublic
May 1, 2025 at 3:59 PM
There is a whole genre of youtube videos explaining how the @mcmastercarr.bsky.social website is so fast. Love the company, love the attention to non react framework of the day JS stuff. www.youtube.com/watch?v=-Ln-...
How is this Website so fast!?
YouTube video by Wes Bos
www.youtube.com
April 26, 2025 at 12:43 PM