Search code examples
rustbuffer

How do i get from string buffer an u32 ? Rust

How do I convert [49] buffer byte to number 1u32 without using String?

fn main() {
    // string "1"
    let buf: &[u8] =[49];
    // not working, expecting [0,0,0,1] to have good result.
    let num = u32::from_ne_bytes(buf.try_into().unwrap());

    println!("{}", num);
}

Result:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: TryFromSliceError(())', src/main.rs:7:49

expected result num: u32 = 1u32;

Solution

  • Assuming you only have one byte, you can convert it to char first, then convert it to a digit.

    fn main() {
    let buf: &[u8] = &[49]; 
    let num = (buf[0] as char).to_digit(10).unwrap();
    println!("{}", num);
}

    Output: 1