Programming Rust, 3rd Edition

Chapter 15. Collections

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We all behave like Maxwell’s demon. Organisms organize. In everyday experience lies the reason sober physicists across two centuries kept this cartoon fantasy alive. We sort the mail, build sand castles, solve jigsaw puzzles, separate wheat from chaff, rearrange chess pieces, collect stamps, alphabetize books, create symmetry, compose sonnets and sonatas, and put our rooms in order, and all this we do requires no great energy, as long as we can apply intelligence.

James Gleick, The Information: A History, a Theory, a Flood

The Rust standard library contains several collections, generic types for storing data in memory. We’ve already been using collections, such as Vec and HashMap, throughout this book. In this chapter, we’ll cover the methods of these two types in detail, along with the other half-dozen standard collections. Before we begin, let’s address a few systematic differences between Rust’s collections and those in other languages.

First, moves and borrowing ...