How do I convert a string into a vector of bytes in rust?

Question

That might be the dumbest Rustlang question ever but I promise I tried my best to find the answer in the documentation or any other place on the web.

I can convert a string to a vector of bytes like this:

let bar = bytes!("some string");

Unfortunately I can't do it this way

let foo = "some string";
let bar = bytes!(foo);

Because bytes! expects a string literal.

But then, how do I get my foo converted into a vector of bytes?

Solution 1

(&str).as_bytes gives you a view of a string as a &[u8] byte slice (that can be called on String since that derefs to str, and there's also String.into_bytes will consume a String to give you a Vec<u8>.

Use the .as_bytes version if you don't need ownership of the bytes.

fn main() {
    let string = "foo";
    println!("{:?}", string.as_bytes()); // prints [102, 111, 111]
}

BTW, The naming conventions for conversion functions are helpful in situations like these, because they allow you to know approximately what name you might be looking for.

Solution 2

 `let v1: Vec<u8> = string.encode_to_vec();`
 `let v2: &[u8]   = string.as_bytes();`

two work difference, in some of library use ownership of bytes !! if you use as_bytes() see compiler error: must be static.

for example: tokio_uring::fs::File::write_at() get a ownership of bytes !!

but if you need borrowing , use as_bytes()