# Function std::str::from_utf8_mut

1.20.0 (const: unstable) · source ·

    pub fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error>

Expand description

Converts a mutable slice of bytes to a mutable string slice.

## Examples

Basic usage:

    use std::str;

    // "Hello, Rust!" as a mutable vector
    let mut hellorust = vec![72, 101, 108, 108, 111, 44, 32, 82, 117, 115, 116, 33];

    // As we know these bytes are valid, we can use `unwrap()`
    let outstr = str::from_utf8_mut(&mut hellorust).unwrap();

    assert_eq!("Hello, Rust!", outstr);

Run

Incorrect bytes:

    use std::str;

    // Some invalid bytes in a mutable vector
    let mut invalid = vec![128, 223];

    assert!(str::from_utf8_mut(&mut invalid).is_err());

Run

See the docs for `Utf8Error` for more details on the kinds of errors that can be returned.