mojones.net

Preface

This rather long post is my attempt to explain to novice programmers how hash tables work. A hash table is a data structure for storing key-value pairs and is part of the standard library of many languages. Depending on your language of choice, you might know hash tables as hashes, HashMaps, dictionaries, dicts, associative arrays, or symbol tables. 

If you're already familiar with hash tables, you'll probably spot many points in this post where I have either simplified things, or avoided talking about them entirely. If you think that any of these simplifications hinder rather than help ...

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I teach a lot of beginner-targeted programming courses, and something that I've experimented with recently is trying to introduce the idea of self-documenting code early on in the learning process. I usually start off by talking about the difference between good and bad names for things (mostly functions and variables, though many of the same arguments apply to class names) , and I've noticed a few common patterns that tend to crop up in beginners code. I thought it might be useful to lay out these common errors in one place.

Single-letter names

OK, we're writing a program ...

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