Rust❤️ 벡터 안에 짝수 인 값의 인덱스 값을 결과값으로 받고 싶을 때 iter().position(|&x| x % 2 == 0)closure

fn main() {
    let vec = vec![1, 9, 3, 3, 13, 2];

    // `iter()` for vecs yields `&i32` and `position()` does not take a reference, so
    // we have to destructure `&i32` to `i32`
    let index_of_first_even_number = vec.iter().position(|&x| x % 2 == 0);
    assert_eq!(index_of_first_even_number, Some(5));
    
    // `into_iter()` for vecs yields `i32` and `position()` does not take a reference, so
    // we do not have to destructure    
    let index_of_first_negative_number = vec.into_iter().position(|x| x < 0);
    assert_eq!(index_of_first_negative_number, None);
}

출처
https://doc.rust-lang.org/rust-by-example/fn/closures/closure_examples/iter_find.html

Searching through iterators - Rust By Example

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