1.0.0[−][src]Trait core::convert::AsRef

pub trait AsRef<T: ?Sized> {
    fn as_ref(&self) -> &T;
}
[−]

Used to do a cheap reference-to-reference conversion.

This trait is similar to AsMut which is used for converting between mutable references. If you need to do a costly conversion it is better to implement From with type &T or write a custom function.

AsRef has the same signature as Borrow, but Borrow is different in few aspects:

Note: This trait must not fail. If the conversion can fail, use a dedicated method which returns an Option<T> or a Result<T, E>.

Generic Implementations

Examples

By using trait bounds we can accept arguments of different types as long as they can be converted a the specified type T.

For example: By creating a generic function that takes an AsRef<str> we express that we want to accept all references that can be converted to &str as an argument. Since both String and &str implement AsRef<str> we can accept both as input argument.

fn is_hello<T: AsRef<str>>(s: T) {
   assert_eq!("hello", s.as_ref());
}

let s = "hello";
is_hello(s);

let s = "hello".to_string();
is_hello(s);Run

Required methods

fn as_ref(&self) -> &T[−]

Performs the conversion.

Implementors

impl AsRef<[u8]> for str[src][−]

impl AsRef<str> for str[src][−]

impl<T> AsRef<[T]> for [T; 0][src][−]

impl<T> AsRef<[T]> for [T; 1][src][−]

impl<T> AsRef<[T]> for [T; 2][src][−]

impl<T> AsRef<[T]> for [T; 3][src][−]

impl<T> AsRef<[T]> for [T; 4][src][−]

impl<T> AsRef<[T]> for [T; 5][src][−]

impl<T> AsRef<[T]> for [T; 6][src][−]

impl<T> AsRef<[T]> for [T; 7][src][−]

impl<T> AsRef<[T]> for [T; 8][src][−]

impl<T> AsRef<[T]> for [T; 9][src][−]

impl<T> AsRef<[T]> for [T; 10][src][−]

impl<T> AsRef<[T]> for [T; 11][src][−]

impl<T> AsRef<[T]> for [T; 12][src][−]

impl<T> AsRef<[T]> for [T; 13][src][−]

impl<T> AsRef<[T]> for [T; 14][src][−]

impl<T> AsRef<[T]> for [T; 15][src][−]

impl<T> AsRef<[T]> for [T; 16][src][−]

impl<T> AsRef<[T]> for [T; 17][src][−]

impl<T> AsRef<[T]> for [T; 18][src][−]

impl<T> AsRef<[T]> for [T; 19][src][−]

impl<T> AsRef<[T]> for [T; 20][src][−]

impl<T> AsRef<[T]> for [T; 21][src][−]

impl<T> AsRef<[T]> for [T; 22][src][−]

impl<T> AsRef<[T]> for [T; 23][src][−]

impl<T> AsRef<[T]> for [T; 24][src][−]

impl<T> AsRef<[T]> for [T; 25][src][−]

impl<T> AsRef<[T]> for [T; 26][src][−]

impl<T> AsRef<[T]> for [T; 27][src][−]

impl<T> AsRef<[T]> for [T; 28][src][−]

impl<T> AsRef<[T]> for [T; 29][src][−]

impl<T> AsRef<[T]> for [T; 30][src][−]

impl<T> AsRef<[T]> for [T; 31][src][−]

impl<T> AsRef<[T]> for [T; 32][src][−]

impl<T> AsRef<[T]> for [T][src][−]

impl<T, '_> AsRef<[T]> for Iter<'_, T>[src][−]

impl<T: ?Sized, U: ?Sized, '_> AsRef<U> for &'_ T where
    T: AsRef<U>, [src][−]

impl<T: ?Sized, U: ?Sized, '_> AsRef<U> for &'_ mut T where
    T: AsRef<U>, [src][−]

impl<T: ?Sized> AsRef<T> for Box<T>

impl<T: ?Sized> AsRef<T> for Arc<T>

impl<T: ?Sized> AsRef<T> for Rc<T>

impl<T: ?Sized + ToOwned, '_> AsRef<T> for Cow<'_, T>

impl AsRef<str> for String

impl AsRef<[u8]> for String

impl<T> AsRef<Vec<T>> for Vec<T>

impl<T> AsRef<[T]> for Vec<T>