std::hash::Hash - Rust
Description: API documentation for the Rust `Hash` trait in crate `std`.
Keywords: rust, rustlang, rust-lang, Hash

# Trait std::hash::Hash 1.0.0 [−] [src]

    pub trait Hash {
        fn hash<H>(&self, state: &mut H) where H: Hasher;

        fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher { ... }
    }

A hashable type.

The `H` type parameter is an abstract hash state that is used by the `Hash` to compute the hash.

If you are also implementing `Eq`, there is an additional property that is important:

    k1 == k2 -> hash(k1) == hash(k2)

In other words, if two keys are equal, their hashes should also be equal. `HashMap` and `HashSet` both rely on this behavior.

## Derivable

This trait can be used with `#[derive]` if all fields implement `Hash`. When `derive`d, the resulting hash will be the combination of the values from calling `.hash()` on each field.

## How can I implement `Hash`?

If you need more control over how a value is hashed, you need to implement the `Hash` trait:

    use std::hash::{Hash, Hasher};

    struct Person {
        id: u32,
        name: String,
        phone: u64,
    }

    impl Hash for Person {
        fn hash<H: Hasher>(&self, state: &mut H) {
            self.id.hash(state);
            self.phone.hash(state);
        }
    }Run

## Required Methods

### `fn hash<H>(&self, state: &mut H) where H: Hasher`

Feeds this value into the state given, updating the hasher as necessary.

## Provided Methods

### `fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher`
1.3.0

Feeds a slice of this type into the state provided.

## Implementors

- `impl<K, V> Hash for BTreeMap<K, V> where K: Hash, V: Hash`
- `impl<'a, B> Hash for Cow<'a, B> where B: Hash + ToOwned + ?Sized`
- `impl<T> Hash for LinkedList<T> where T: Hash`
- `impl Hash for String`
- `impl<T> Hash for Vec<T> where T: Hash`
- `impl<A> Hash for VecDeque<A> where A: Hash`
- `impl<T> Hash for BTreeSet<T> where T: Hash`
- `impl<E> Hash for EnumSet<E> where E: Hash`
- `impl<T> Hash for Bound<T> where T: Hash`
- `impl<T> Hash for Box<T> where T: Hash + ?Sized`
- `impl<T> Hash for Arc<T> where T: Hash + ?Sized`
- `impl<T> Hash for Rc<T> where T: Hash + ?Sized`
- `impl<T> Hash for Discriminant<T>`
- `impl Hash for bool`
- `impl Hash for char`
- `impl Hash for str`
- `impl<T> Hash for [T] where T: Hash`
- `impl<'a, T> Hash for &'a T where T: Hash + ?Sized`
- `impl<'a, T> Hash for &'a mut T where T: Hash + ?Sized`
- `impl<T> Hash for *const T`
- `impl<T> Hash for *mut T`
- `impl<T> Hash for Wrapping<T> where T: Hash`
- `impl<T> Hash for NonZero<T> where T: Zeroable + Hash`
- `impl<Ret> Hash for fn() -> Ret`
- `impl<Ret> Hash for extern fn() -> Ret`
- `impl<Ret> Hash for unsafe fn() -> Ret`
- `impl<Ret> Hash for unsafe extern fn() -> Ret`
- `impl<Ret, A> Hash for fn(A) -> Ret`
- `impl<Ret, A> Hash for extern fn(A) -> Ret`
- `impl<Ret, A> Hash for extern fn(A, ...) -> Ret`
- `impl<Ret, A> Hash for unsafe fn(A) -> Ret`
- `impl<Ret, A> Hash for unsafe extern fn(A) -> Ret`
- `impl<Ret, A> Hash for unsafe extern fn(A, ...) -> Ret`
- `impl<Ret, A, B> Hash for fn(A, B) -> Ret`
- `impl<Ret, A, B> Hash for extern fn(A, B) -> Ret`
- `impl<Ret, A, B> Hash for extern fn(A, B, ...) -> Ret`
- `impl<Ret, A, B> Hash for unsafe fn(A, B) -> Ret`
- `impl<Ret, A, B> Hash for unsafe extern fn(A, B) -> Ret`
- `impl<Ret, A, B> Hash for unsafe extern fn(A, B, ...) -> Ret`
- `impl<Ret, A, B, C> Hash for fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> Hash for extern fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> Hash for extern fn(A, B, C, ...) -> Ret`
- `impl<Ret, A, B, C> Hash for unsafe fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> Hash for unsafe extern fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> Hash for unsafe extern fn(A, B, C, ...) -> Ret`
- `impl<Ret, A, B, C, D> Hash for fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> Hash for extern fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> Hash for extern fn(A, B, C, D, ...) -> Ret`
- `impl<Ret, A, B, C, D> Hash for unsafe fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> Hash for unsafe extern fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> Hash for unsafe extern fn(A, B, C, D, ...) -> Ret`
- `impl<Ret, A, B, C, D, E> Hash for fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> Hash for extern fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> Hash for extern fn(A, B, C, D, E, ...) -> Ret`
- `impl<Ret, A, B, C, D, E> Hash for unsafe fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> Hash for unsafe extern fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> Hash for unsafe extern fn(A, B, C, D, E, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F> Hash for fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> Hash for extern fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> Hash for extern fn(A, B, C, D, E, F, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F> Hash for unsafe fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> Hash for unsafe extern fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> Hash for unsafe extern fn(A, B, C, D, E, F, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> Hash for fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> Hash for extern fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> Hash for extern fn(A, B, C, D, E, F, G, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> Hash for unsafe fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern fn(A, B, C, D, E, F, G, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> Hash for fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> Hash for extern fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> Hash for extern fn(A, B, C, D, E, F, G, H, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern fn(A, B, C, D, E, F, G, H, I, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern fn(A, B, C, D, E, F, G, H, I, J, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, J, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern fn(A, B, C, D, E, F, G, H, I, J, K, L, ...) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern fn(A, B, C, D, E, F, G, H, I, J, K, L, ...) -> Ret`
- `impl<T> Hash for PhantomData<T> where T: ?Sized`
- `impl Hash for RangeFull`
- `impl<Idx> Hash for Range<Idx> where Idx: Hash`
- `impl<Idx> Hash for RangeFrom<Idx> where Idx: Hash`
- `impl<Idx> Hash for RangeTo<Idx> where Idx: Hash`
- `impl<Idx> Hash for RangeInclusive<Idx> where Idx: Hash`
- `impl<Idx> Hash for RangeToInclusive<Idx> where Idx: Hash`
- `impl Hash for Ordering`
- `impl Hash for TypeId`
- `impl<T> Hash for [T; 0] where T: Hash`
- `impl<T> Hash for [T; 1] where T: Hash`
- `impl<T> Hash for [T; 2] where T: Hash`
- `impl<T> Hash for [T; 3] where T: Hash`
- `impl<T> Hash for [T; 4] where T: Hash`
- `impl<T> Hash for [T; 5] where T: Hash`
- `impl<T> Hash for [T; 6] where T: Hash`
- `impl<T> Hash for [T; 7] where T: Hash`
- `impl<T> Hash for [T; 8] where T: Hash`
- `impl<T> Hash for [T; 9] where T: Hash`
- `impl<T> Hash for [T; 10] where T: Hash`
- `impl<T> Hash for [T; 11] where T: Hash`
- `impl<T> Hash for [T; 12] where T: Hash`
- `impl<T> Hash for [T; 13] where T: Hash`
- `impl<T> Hash for [T; 14] where T: Hash`
- `impl<T> Hash for [T; 15] where T: Hash`
- `impl<T> Hash for [T; 16] where T: Hash`
- `impl<T> Hash for [T; 17] where T: Hash`
- `impl<T> Hash for [T; 18] where T: Hash`
- `impl<T> Hash for [T; 19] where T: Hash`
- `impl<T> Hash for [T; 20] where T: Hash`
- `impl<T> Hash for [T; 21] where T: Hash`
- `impl<T> Hash for [T; 22] where T: Hash`
- `impl<T> Hash for [T; 23] where T: Hash`
- `impl<T> Hash for [T; 24] where T: Hash`
- `impl<T> Hash for [T; 25] where T: Hash`
- `impl<T> Hash for [T; 26] where T: Hash`
- `impl<T> Hash for [T; 27] where T: Hash`
- `impl<T> Hash for [T; 28] where T: Hash`
- `impl<T> Hash for [T; 29] where T: Hash`
- `impl<T> Hash for [T; 30] where T: Hash`
- `impl<T> Hash for [T; 31] where T: Hash`
- `impl<T> Hash for [T; 32] where T: Hash`
- `impl<T> Hash for Option<T> where T: Hash`
- `impl<T, E> Hash for Result<T, E> where E: Hash, T: Hash`
- `impl Hash for u8`
- `impl Hash for u16`
- `impl Hash for u32`
- `impl Hash for u64`
- `impl Hash for usize`
- `impl Hash for i8`
- `impl Hash for i16`
- `impl Hash for i32`
- `impl Hash for i64`
- `impl Hash for isize`
- `impl Hash for u128`
- `impl Hash for i128`
- `impl Hash for ()`
- `impl<A> Hash for (A,) where A: Hash`
- `impl<A, B> Hash for (A, B) where A: Hash, B: Hash`
- `impl<A, B, C> Hash for (A, B, C) where A: Hash, B: Hash, C: Hash`
- `impl<A, B, C, D> Hash for (A, B, C, D) where A: Hash, B: Hash, C: Hash, D: Hash`
- `impl<A, B, C, D, E> Hash for (A, B, C, D, E) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash`
- `impl<A, B, C, D, E, F> Hash for (A, B, C, D, E, F) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash`
- `impl<A, B, C, D, E, F, G> Hash for (A, B, C, D, E, F, G) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash,
  G: Hash`
- `impl<A, B, C, D, E, F, G, H> Hash for (A, B, C, D, E, F, G, H) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash,
  G: Hash,
  H: Hash`
- `impl<A, B, C, D, E, F, G, H, I> Hash for (A, B, C, D, E, F, G, H, I) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash,
  G: Hash,
  H: Hash,
  I: Hash`
- `impl<A, B, C, D, E, F, G, H, I, J> Hash for (A, B, C, D, E, F, G, H, I, J) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash,
  G: Hash,
  H: Hash,
  I: Hash,
  J: Hash`
- `impl<A, B, C, D, E, F, G, H, I, J, K> Hash for (A, B, C, D, E, F, G, H, I, J, K) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash,
  G: Hash,
  H: Hash,
  I: Hash,
  J: Hash,
  K: Hash`
- `impl<A, B, C, D, E, F, G, H, I, J, K, L> Hash for (A, B, C, D, E, F, G, H, I, J, K, L) where A: Hash,
  B: Hash,
  C: Hash,
  D: Hash,
  E: Hash,
  F: Hash,
  G: Hash,
  H: Hash,
  I: Hash,
  J: Hash,
  K: Hash,
  L: Hash`
- `impl Hash for Error`
- `impl Hash for CString`
- `impl Hash for CStr`
- `impl Hash for OsString`
- `impl Hash for OsStr`
- `impl Hash for FileType`
- `impl Hash for ErrorKind`
- `impl Hash for IpAddr`
- `impl Hash for Ipv6MulticastScope`
- `impl Hash for Ipv4Addr`
- `impl Hash for Ipv6Addr`
- `impl Hash for SocketAddr`
- `impl Hash for SocketAddrV4`
- `impl Hash for SocketAddrV6`
- `impl<'a> Hash for Prefix<'a>`
- `impl<'a> Hash for PrefixComponent<'a>`
- `impl<'a> Hash for Component<'a>`
- `impl Hash for PathBuf`
- `impl Hash for Path`
- `impl Hash for Duration`

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