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Convert Result -> Option

Đôi khi bạn sẽ cần convert từ:

  • Ok(v) –> Some(v)
  • hoặc ngược lại, Err(e) –> Some(e)

.ok()

// .ok(v) = Some(v)
let x: Result<u32, &str> = Ok(2);
assert_eq!(x.ok(), Some(2));

let y: Result<u32, &str> = Err("Nothing here");
assert_eq!(y.ok(), None);

.err()

// .err()
let x: Result<u32, &str> = Ok(2);
assert_eq!(x.err(), None);

let x: Result<u32, &str> = Err("Nothing here");
assert_eq!(x.err(), Some("Nothing here"));