How to Convert Between Collection Types in Rust

Use the into_iter() method combined with the collect() method to convert between collection types like Vec, HashMap, and String.

let vec = vec![1, 2, 3];
let hash_map: std::collections::HashMap<i32, i32> = vec.into_iter().map(|x| (x, x * 2)).collect();

The into_iter() consumes the original collection and yields its elements, while collect() gathers those elements into the target type specified by the variable annotation.

Converting collections in Rust is like repacking items from one box into another. You take the items out of the first box one by one and place them into the new box, which might be a different shape or size. This process ensures you have the data in the format you need for the next step of your program.