rust 中哪一个更惯用？

Question

Which is more idiomatic rust in this case,

//This is a C like a syntax where you can get the value at a location through *.
fn largest_i32(list: &[i32])-> i32{
    let mut largest = list[0];

    for item in list.iter(){
        if *item > largest{
            largest = *item;
        }

    };
    largest
}

or

//This syntax seems confusing to me, Is rust doing derefrecing iteself.
fn largest_i32(list: &[i32]) -> i32 {
    let mut largest = list[0];

    for &item in list.iter() {
        if item > largest {
            largest = item;
        }
    }

    largest
}

Answer 1

In this particular case, the most idiomatic solution would be

fn largest_i32(list: &[i32]) -> i32 {
    *list.iter().max().unwrap()
}

But if I had to choose between the two functions you wrote, I'd pick the second one.

 //This syntax seems confusing to me, Is rust doing derefrecing iteself.

for loops accept a pattern . list.iter() is an iterator over items with the type &i32 , which is pattern-matched against &item , so item is destructured into a i32 . This has the same effect as dereferencing it.

Pattern matching is pervasive in Rust. You can read about all the places where patterns are allowed here .