How do I convert a Vector of bytes (u8) to a string?

To convert a slice of bytes to a string slice (assuming a UTF-8 encoding):

use std::str;

//
// pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error>
//
// Assuming buf: &[u8]
//

fn main() {

    let buf = &[0x41u8, 0x41u8, 0x42u8];

    let s = match str::from_utf8(buf) {
        Ok(v) => v,
        Err(e) => panic!("Invalid UTF-8 sequence: {}", e),
    };

    println!("result: {}", s);
}

The conversion is in-place, and does not require an allocation. You can create a String from the string slice if necessary by calling .to_owned() on the string slice (other options are available).

If you are sure that the byte slice is valid UTF-8, and you don’t want to incur the overhead of the validity check, there is an unsafe version of this function, from_utf8_unchecked, which has the same behavior but skips the check.

If you need a String instead of a &str, you may also consider String::from_utf8 instead.

The library references for the conversion function:

• std::str::from_utf8
• std::str::from_utf8_unchecked
• std::string::String::from_utf8