Rust

5.6    HashSets

In addition to HashMaps, Rust also has HashSets. The key difference between a HashSet and a HashMap is that a HashSet stores only unique keys without any associated values, while a HashMap stores key-value pairs, allowing each key to have an associated value. Consider the example HashSet shown in Listing 5.33.

let mut words: HashSet<&str> = HashSet::new();words.insert("Hello");words.insert("world");words.insert("Rust");words.insert("Programming");  

Listing 5.33     Storing Unique Words Using a HashSet

Note

Like HashMap, HashSet is also not included by default, and you must include it manually using the use statement, as in use std::collections::HashSet;.

Using a HashSet offers an organized and efficient for managing collections ...