Rust should not have provided `unwrap`(thecodedmessage.com)

  Regex::new(r"\bstruct\b").unwrap()
  // vs.
  Regex::new(r"\bstruct\b").expect("bad regex string literal")

    struct IVec2(i32, i32);

    impl IVec2 {
        fn parse(d: [u8; 8]) -> Self {
            Vec2(i32::from_le_bytes(d[0..4].try_into().unwrap()),
                 i32::from_le_bytes(d[4..8].try_into().unwrap()))
        }
    }

  if res.is_err() {
    // Do something
    return;
  }

  let res = res.unwrap();

    fn main() {
        let _my_num: u32 = "not a number".parse().unwrap();
    }

    thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ParseIntError { kind: InvalidDigit }', src/main.rs:2:47

    fn main() -> Result<(), Box<dyn std::error::Error>> {
        let _my_num: u32 = "not a number".parse()?;
    
        Ok(())
    }

    Error: ParseIntError { kind: InvalidDigit }

    let val = v.ok_or(anyhow!("Error message goes here"))?;

    fn square(v: &Option<f32>) -> f32 {
        Ok(v.unwrap()*v.unwrap())
    }

    fn square(v: &Option<f32>) -> Result<f32, Error> {
        let val = v.ok_or(anyhow!("None value sent to square"))?;
        Ok(val*val)
    }