How to write a Rust function that takes an iterator?

Question

I\'d like to write a function that accepts an iterator and returns the results of some operations on it. Specifically, I\'m trying to iterate over the values of a Has

Answer 1

You want to use generics here:

fn find_min<'a, I>(vals: I) -> Option<&'a u32>
where
    I: Iterator,
{
    vals.min()
}

Traits can be used in two ways: as bounds on type parameters and as trait objects. The book The Rust Programming Language has a chapter on traits and a chapter on trait objects that explain these two use cases.

Additionally, you often want to take something that implements IntoIterator as this can make the code calling your function nicer:

fn find_min<'a, I>(vals: I) -> Option<&'a u32>
where
    I: IntoIterator,
{
    vals.into_iter().min()
}