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

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

A cheap reference-to-reference conversion. Used to convert a value to a reference value within generic code.

AsRef is very similar to, but serves a slightly different purpose than, Borrow.

AsRef is to be used when wishing to convert to a reference of another type. Borrow is more related to the notion of taking the reference. It is useful when wishing to abstract over the type of reference (&T, &mut T) or allow both the referenced and owned type to be treated in the same manner.

The key difference between the two traits is the intention:

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

Both String and &str implement AsRef<str>:

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.

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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]

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