Converting a str to a &[u8]

Question

This seems trivial, but I cannot find a way to do it.

For example,

fn f(s: &[u8]) {}  pub fn main() {     let x = "a";     f(x) } 

Fails to compile with:

error: mismatched types:  expected `&[u8]`,     found `&str` (expected slice,     found str) [E0308] 

documentation, however, states that:

The actual representation of strs have direct mappings to slices: &str is the same as &[u8].

Answer 1

You can use the as_bytes method:

fn f(s: &[u8]) {}  pub fn main() {     let x = "a";     f(x.as_bytes()) } 

or, in your specific example, you could use a byte literal:

let x = b"a"; f(x)