Option and Result
The types represent optional data:
fn main() {
let numbers = vec![10, 20, 30];
let first: Option<&i8> = numbers.first();
println!("first: {first:?}");
let idx: Result<usize, usize> = numbers.binary_search(&10);
println!("idx: {idx:?}");
}first: Some(10)
idx: Ok(0)Notes
- Option and Result are widely used not just in the standard library.
- Option<&T> has zero space overhead compared to &T.
- Result is the standard type to implement error handling as we will see on Day 3.
- binary_search returns Result<usize, usize>.
- If found, Result::Ok holds the index where the element is found.
- Otherwise, Result::Err contains the index where such an element should be inserted.