I need to find an index of an element in a vector of strings. This is what I got so far:
fn main() {
let test: Vec<String> = vec![
"one".to_string(),
"two".to_string(),
"three".to_string(),
"four".to_string(),
];
let index: i32 = test
.iter()
.enumerate()
.find(|&r| r.1.to_string() == "two".to_string())
.unwrap()
.0;
}
It produces an error:
error[E0308]: mismatched types
--> src/main.rs:9:22
|
9 | let index: i32 = test
| ______________________^
10 | | .iter()
11 | | .enumerate()
12 | | .find(|&r| r.1.to_string() == "two".to_string())
13 | | .unwrap()
14 | | .0;
| |__________^ expected i32, found usize
I assume that's because enumerate() returns a tuple of (usize, _) (correct me if I'm wrong), but how do I convert usize to i32 here? If there is a better approach, I'm open to suggestions.
ベストアンサー1
I think you should look at the position method instead.
fn main() {
let test = vec!["one", "two", "three"];
let index = test.iter().position(|&r| r == "two").unwrap();
println!("{}", index);
}
You can test it here.
これはどのイテレータでも機能するため、イテレータを生成するベクトル、配列、スライスにも使用できることに注意してください。