rustHow to use a generator map in Rust?

Using a generator map in Rust is a great way to create a map of values from an iterator. It is similar to the map method, but instead of returning a new iterator, it returns a HashMap.

Example code

let v = vec![1, 2, 3];
let m: HashMap<_, _> = v.into_iter().map(|x| (x, x * x)).collect();

Output example

{1: 1, 2: 4, 3: 9}

Code explanation

• let v = vec![1, 2, 3];: This creates a vector with the values 1, 2, and 3.

• let m: HashMap<_, _> =: This creates a HashMap with the type of the keys and values left unspecified.

• v.into_iter().map(|x| (x, x * x)): This creates an iterator from the vector v and maps each value to a tuple of the value and its square.

• collect(): This collects the iterator into a HashMap.

Helpful links

• Rust Documentation - HashMap
• Rust Documentation - Iterator

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