Mastering Rust - Second Edition

Hashmaps

Rust also provides us with maps, which can be used to store key-value data. They come from the std::collections module and are named HashMap. They are created with the HashMap::new constructor function:

// hashmaps.rsuse std::collections::HashMap; fn main() {     let mut fruits = HashMap::new();     fruits.insert("apple", 3);    fruits.insert("mango", 6);    fruits.insert("orange", 2);    fruits.insert("avocado", 7);    for (k, v) in &fruits {        println!("I got {} {}", v, k);    }    fruits.remove("orange");    let old_avocado = fruits["avocado"];    fruits.insert("avocado", old_avocado + 5);    println!("\nI now have {} avocados", fruits["avocado"]);}

In the preceding code, we created a new HashMap called fruits. We then insert some fruits into our fruits map, along ...