[hasenj]

It was slow because at first I put the import inside the function. Moving it out improved the python performance to 20ms (as I mentioned in another comment).

The javascript version runs in 15ms.

> In the real world, things like haversine are implemented as C extensions

Having to write C-extensions is, well a point of friction, and adds complexity.

If you just used a native language to begin with, the simple straight forward code would work just fine.

Btw the source is here, and it also includes the csv file. https://bitbucket.org/hasenj/geodb/src

[tychver]

Yeah, that'll do it!

C extensions are a core part of Ruby. A big chunk of the std lib is implemented in C. You shouldn't be afraid of writing a tiny bit of C. Ruby and Python are scripting languages. They're literally designed for scripting another language.

The JIT for Ruby 3 is well underway, so in a bit it'll be a complete non-issue anyway.