Exercises in Programming Style–Code Golf

NOTE : read the rest of the series, or check out the source code.

If you enjoy read­ing these exer­cises then please buy Crista’s book to sup­port her work.


Fol­low­ing on from the last post, we will look at the Code Golf style today.


Style 6 – Code Golf

This style came from Code Golf, which is also often associated APL, another language that I’ve had a lot of fun with in recent months!



  • As few lines of code as possible


Well, cover your eyes folks, this one ain’t pretty…

The lines are so long that you have to click on the image to view it in full just to be able to read the original source code properly…


But, but, but, it does solve the term frequency problem in only 3 lines of code! 3 lines!

3 unbelievably hard to read lines of code 

And that’s where this style falls down, the pursuit for brevity often comes at the expense of readability.

It can also be argued that what we have done here is rearranging the steps in fewer lines without necessarily reducing the number of steps. That is, we haven’t reduced the number of things that needs to be kept in our head in order to understand what this piece of code is doing to solve the problem.

On this note, APL’s syntax is often described as unreadable, but I think the problem is not readability but rather familiarity. Its syntax and built-in abstractions are both alien to most developers, and very different to what they’re used to.

When I was learning API, there were a few mental hurdles that I needed to jump through:

  • glyph-based function names
  • functions have monadic (i.e. prefix) and dyadic (i.e. infix) forms
  • everything works on matrices as well as scalars
  • precedence always flow from right-to-left, except when braces are used

once I built up some familiarity with the language I actually found APL pretty easy to read.


You can find all the source code for this exercise here.

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Yan Cui

I’m an AWS Serverless Hero and the author of Production-Ready Serverless. I have run production workload at scale in AWS for nearly 10 years and I have been an architect or principal engineer with a variety of industries ranging from banking, e-commerce, sports streaming to mobile gaming. I currently work as an independent consultant focused on AWS and serverless.

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