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Show HN: Got sick of ads, so I made my own logic puzzle site

https://puzzlelair.com/
29•HaxleRose•2h ago•23 comments

Show HN: Revenant – automatic LLM powered reverse engineering and reimplement

3•sylwester•43m ago•0 comments

Show HN: Teach your kids perfect pitch

https://github.com/paytonjjones/bsharp
182•paytonjjones•1d ago•126 comments

Show HN: Criterion Closet as a website – pull any of 1,247 films off the shelf

https://the-criterion-closet.vercel.app
156•olievans•2d ago•49 comments

Show HN: Recall – Local project memory for Claude Code

https://github.com/raiyanyahya/recall
123•mateenah•17h ago•74 comments

Show HN: I rebuilt the only parts of my IDE I use, in Rust, over a weekend

https://github.com/kyle-ssg/kyde
6•kyle-ssg•2h ago•2 comments

Show HN: I rebuilt Jobs To Be Done on scientific foundations and open-sourced it

https://github.com/zamesin/Next-Move-Theory-Canon-and-Skills
12•zamesin•2h ago•0 comments

Show HN: SindriKit – A C framework applying dependency injection to exploit dev

https://sibouzitoun.tech/articles/sindrkit
3•sibouzitoun•2h ago•0 comments

Show HN: KeyGhost – Keyboard app launcher for macOS

https://keyghost.dev/
5•3stacks•4h ago•1 comments

Show HN: PauseRead – hosted read-later with Pocket HTML import

https://pauseread.com/pocket-alternative
3•YuriiKholodkov•2h ago•0 comments

Show HN: Bowora – A launchpad for build-in-public founders

https://bowora.com
4•Nimaaksoy•3h ago•0 comments

Show HN: MiniPCs.zip – Charting the Pareto frontier of Mini PCs

https://minipcs.zip
40•yathern•1d ago•21 comments

Show HN: Ze.sh – a z.sh-derived directory jumper that uses an event clock

https://github.com/jghub/ze
4•jghub•3h ago•0 comments

Show HN: Duckle a drag-and-drop visual pipeline designer

https://github.com/slothflowlabs/duckle
3•souravroy78•3h ago•4 comments

Show HN: Prismag – Per-block model routing for the terminal and any IDE

https://github.com/rufus-SD/prismag
3•arthur-G•5h ago•0 comments

Show HN: A site where people pay me money for no reason

https://payfornoreason.com
8•qane•3h ago•18 comments

Show HN: CleverCrow: give tokens to your favorite projects

https://clevercrow.io
40•zhubert•19h ago•57 comments

Show HN: Crespo – Tree-sitter AST blueprints instead of raw code for LLMs

https://github.com/hrudulmmn/crespo
9•ByteJoseph•11h ago•1 comments

Show HN: Pulse – Dashboard for Claude Code, approve tool calls from your phone

https://github.com/nikitadoudikov/claude-pulse
38•nikitadvd•1d ago•14 comments

Show HN: TownSquare, a tiny presence layer for websites

https://townsquare.cauenapier.com/
260•cauenapier•2d ago•148 comments

Show HN: StartupsBR – A map of Brazilian startups

https://www.startupsbr.com/sao-paulo
16•leonagano•2d ago•7 comments

Show HN: StartupWiki – A Free Alternative to Crunchbase

https://startupwiki.tech/
227•shpran•1d ago•69 comments

Show HN: Make PDFs look scanned (CLI or in the browser via WASM)

https://github.com/overflowy/make-look-scanned
150•overflowy•1d ago•63 comments

Show HN: Brain Frog – Can you be random enough for 11 lines of JavaScript?

https://brainfrog.lol
15•AlexanderZ•3d ago•10 comments

Show HN: Microcrad – Micrograd Reimplemented in C

https://github.com/oraziorillo/microcrad
78•oraziorillo•5d ago•28 comments

Show HN: NagMeLater – Reminders and to-do list, inside your WhatsApp

https://nagmelater.com
2•mehulfanawala•9h ago•0 comments

Show HN: Talos – Open-source WASM interpreter for Lean

https://github.com/cajal-technologies/talos
105•mfornet•4d ago•28 comments

Show HN: MemoryOps – governed memory infrastructure for AI assistants

https://github.com/patibandlavenkatamanideep/memoryops-ai
5•pvmanideep20•9h ago•0 comments

Show HN: We post-trained a model that pen tests instead of refusing

https://www.argusred.com/cli
91•dk189•2d ago•40 comments

Show HN: My Windows XP portfolio with working Game Boy and iPod

https://mitchivin.com/
70•mitchivin•1d ago•34 comments
Open in hackernews

Show HN: Fahmatrix – A Lightweight, Pandas-Like DataFrame Library for Java

https://github.com/moustafa-nasr/fahmatrix
46•mousomashakel•1y ago
Hey HN, I’ve built Fahmatrix, a minimal, fast Java library for working with tabular data — inspired by Python’s pandas, but designed for performance and simplicity on the JVM.

After working extensively with Python’s data stack, I often ran into limitations related to speed, especially in larger or long-running data workflows. So I built Fahmatrix from scratch to offer similar APIs for manipulating CSVs, performing summary statistics, slicing rows/columns, and more — but all in Java.

Features:

Lightweight and dependency-free

CSV/TSV import with auto-headers

Series/DataFrame structures (like pandas)

describe(), mean(), stdDev(), percentile() and more

Fast parallel operations on numeric columns

Java 17+ support

Docs: https://moustafa-nasr.github.io/Fahmatrix/ GitHub: https://github.com/moustafa-nasr/fahmatrix

I’d love feedback from the Java and data communities — especially if you’ve ever wanted a simple dataframe utility in Java without needing full-scale ML libraries.

Happy to answer any questions!

Comments

rickette•1y ago
Congrats on putting this out there. There isn't a de facto pandas-like library in Java like you said. But for Kotlin there is: https://github.com/Kotlin/dataframe
mousomashakel•1y ago
Thanks so much! Yep, I’ve seen the Kotlin DataFrame lib — very elegant. Fahmatrix is meant for plain Java users who want similar capabilities without switching ecosystems. Appreciate the support!
uwemaurer•1y ago
Always great to see efforts to make working with data frames easier. Here are some similar data frame libraries for Java:

https://github.com/jtablesaw/tablesaw

https://github.com/dflib/dflib

My preferred way is just use duckdb java API. I didn't see anything better in performance/efficiency. Also a SQL query is often easier to write

theanonymousone•1y ago
Yes. It has bothered me for a long time too. Maybe the best mix is a dataframe library with basic operations (column select, non-null etc), which also allows SQL for more complex stuff?
radus•1y ago
Polars and duckdb interoperate nicely and can enable this flexibility
theanonymousone•1y ago
Does Polars have a Java library?
mousomashakel•1y ago
Totally agree that SQL can be the best tool for many jobs. My goal with Fahmatrix is to serve the opposite niche: where devs want something that's Java-native, procedural, and simple without reaching for an external engine. SQL support or DSL might come later though — I see the appeal.
skanga•1y ago
What about Tablesaw, Apache Arrow? How does this compare ...
mousomashakel•1y ago
Good question. I’ll publish benchmarks soon, but the core difference is that Fahmatrix is fully Java, no JNI, and minimalistic — ideal for small projects or environments like Android. Tablesaw and Arrow are more powerful, but heavier. Fahmatrix aims to be the “just enough” middle ground.
owlstuffing•1y ago
Nice!

I’m currently using manifold-sql with duckdb for this.

mousomashakel•1y ago
Thanks! That’s a great combo — manifold-sql + duckdb gives you strong typing with powerful SQL under the hood. Fahmatrix is aiming to complement that approach for cases where you want quick, native Java code without SQL — e.g., when building data flows or custom logic inline. Would love to hear if you’ve hit any pain points that a Java-native approach could help with.
theanonymousone
•
1y ago
Sure. So maybe notehr comment would be to make it (particularly the Series class), as compatible with Java Streams as possible.

Next step would likely be compatibility with popular libraries such as Apache Commons Math: https://commons.apache.org/proper/commons-math/userguide/sta...

mousomashakel•1y ago
Thanks! I'm aware of those great projects. Fahmatrix aims to offer a lightweight, dependency-free alternative that’s easy to embed in any Java app. DuckDB is super impressive, especially for SQL-heavy tasks — but my goal is more about a native, fluent API for those who prefer direct Java code over SQL.