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rust handle result

Quantum answered on March 7, 2023 Popularity 7/10 Helpfulness 2/10

answer rust handle result

rust handle result

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fn main() {
    let res = give_an_ok_result(false);
    
    // Method 1: use match
    match res {
        Ok(r) => {
            println!("Result succeeded");
            assert_eq!(r, 10);
        },
        Err(e) => {
            println!("Result errored!"); // This will run, given res will be an Err
            assert_eq!(e, false);
        }
    }
    
    // Method 2: use if
    if let Err(e) = res {
        println!("Error: {}", e); // "Error: false"
    }
    // You can also use `if let Ok(x) = res` to handle the Ok outcome
    
    // Method 3: use expect
    res.expect("You asked res to be an Err");
    // This causes the program to panic and due to that, it is not good practice to use expect
    
    // Method 4: Use unwrap_or
    assert_eq!(res.unwrap_or(3i32), 3i32);
    // This returns the Ok value in an Ok outcome, or the specified default for an Err outcome
    // The 1st argument has to be the same type as the type of Ok of the Result
    
    // There's other ways to handle results, these are only some.
}

fn give_an_ok_result(give_some: bool) -> Result<i32, bool> {
    match give_some {
        true => return Ok(10),
        false => return Err(false)
    }
}

Popularity 7/10 Helpfulness 2/10 Language rust

Source: Grepper

Tags: handle rust whatever

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Contributed on Mar 07 2023

Quantum

0 Answers Avg Quality 2/10

rust handle result

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