FromIterator

FromIterator lets you build a collection from an Iterator.

fn main() {
    let primes = vec![2, 3, 5, 7];
    let prime_squares = primes
        .into_iter()
        .map(|prime| prime * prime)
        .collect::<Vec<_>>();
}

Iterator implements fn collect<B>(self) -> B where B: FromIterator<Self::Item>, Self: Sized collect enables to convert an interator into a collection. Here it enables to reconstruct a vector.

There are also implementations which let you do cool things like convert an Iterator<Item = Result<V, E>> into a Result<Vec<V>, E>.

Add this line to print the computed squares: println!("{:?}", prime_squares)