Function core::str::from_utf8 1.0.0
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[src]
pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error>
Converts a slice of bytes to a string slice.
A string slice (&str) is made of bytes (u8), and a byte slice (&[u8])
is made of bytes, so this function converts between the two. Not all byte
slices are valid string slices, however: &str requires that it is valid
UTF-8. from_utf8() checks to ensure that the bytes are valid UTF-8, and
then does the conversion.
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, consider
String::from_utf8().
Because you can stack-allocate a [u8; N], and you can take a &[u8] of
it, this function is one way to have a stack-allocated string. There is
an example of this in the examples section below.
Errors
Returns Err if the slice is not UTF-8 with a description as to why the
provided slice is not UTF-8.
Examples
Basic usage:
use std::str; // some bytes, in a vector let sparkle_heart = vec![240, 159, 146, 150]; // We know these bytes are valid, so just use `unwrap()`. let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap(); assert_eq!("💖", sparkle_heart);Run
Incorrect bytes:
use std::str; // some invalid bytes, in a vector let sparkle_heart = vec![0, 159, 146, 150]; assert!(str::from_utf8(&sparkle_heart).is_err());Run
See the docs for Utf8Error for more details on the kinds of
errors that can be returned.
A "stack allocated string":
use std::str; // some bytes, in a stack-allocated array let sparkle_heart = [240, 159, 146, 150]; // We know these bytes are valid, so just use `unwrap()`. let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap(); assert_eq!("💖", sparkle_heart);Run