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.

Types implementing `Hash` are able to be `hash`ed with an instance of `Hasher`.

## Implementing `Hash`

You can derive `Hash` with `#[derive(Hash)]` if all fields implement `Hash`. The resulting hash will be the combination of the values from calling `hash` on each field.

    #[derive(Hash)]
    struct Rustacean {
        name: String,
        country: String,
    }Run

If you need more control over how a value is hashed, you can of course implement the `Hash` trait yourself:

    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

## `Hash` and `Eq`

When implementing both `Hash` and `Eq`, it is important that the following property holds:

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

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

Thankfully, you won't need to worry about upholding this property when deriving both `Eq` and `Hash` with `#[derive(PartialEq, Eq, Hash)]`.

## Required Methods

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

Feeds this value into the given `Hasher`.

# Examples

    use std::collections::hash_map::DefaultHasher;
    use std::hash::{Hash, Hasher};

    let mut hasher = DefaultHasher::new();
    7920.hash(&mut hasher);
    println!("Hash is {:x}!", hasher.finish());Run

## 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 given `Hasher`.

# Examples

    use std::collections::hash_map::DefaultHasher;
    use std::hash::{Hash, Hasher};

    let mut hasher = DefaultHasher::new();
    let numbers = [6, 28, 496, 8128];
    Hash::hash_slice(&numbers, &mut hasher);
    println!("Hash is {:x}!", hasher.finish());Run

## Implementors

- `impl<Ret, A, B, C, D, E, F, G, H> Hash for fn(A, B, C, D, E, F, G, H) -> Ret` | [src]

- `impl Hash for u32` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, ...) -> Ret` | [src]

- `impl<Ret, A, B> Hash for extern "C" fn(A, B, ...) -> Ret` | [src]

- `impl<T> Hash for [T; 31] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E> Hash for fn(A, B, C, D, E) -> Ret` | [src]

- `impl Hash for ()` | [src]

- `impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret` | [src]

- `impl<Ret, A, B, C> Hash for extern "C" fn(A, B, C, ...) -> Ret` | [src]

- `impl<Ret> Hash for unsafe extern "C" fn() -> Ret` | [src]

- `impl<'a, T> Hash for &'a mut T where T: Hash + ?Sized,` | [src]

- `impl<T> Hash for [T; 23] where T: Hash,` | [src]

- `impl<Ret, A> Hash for extern "C" fn(A) -> Ret` | [src]

- `impl<Ret, A> Hash for fn(A) -> Ret` | [src]

- `impl<T> Hash for [T; 19] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F> Hash for fn(A, B, C, D, E, F) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(A, B, C, D, E) -> Ret` | [src]

- `impl<T> Hash for [T; 20] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, ...) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E> Hash for extern "C" fn(A, B, C, D, E) -> Ret` | [src]

- `impl<Ret, A, B> Hash for unsafe fn(A, B) -> Ret` | [src]

- `impl Hash for NoneError` | [src]

- `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 + ?Sized,` | [src]

- `impl<A> Hash for (A,) where A: Hash + ?Sized,` | [src]

- `impl<T> Hash for [T; 0] where T: Hash,` | [src]

- `impl<T> Hash for [T; 12] where T: Hash,` | [src]

- `impl Hash for NonZeroU128` | [src]

- `impl<Ret, A, B> Hash for unsafe extern "C" fn(A, B) -> Ret` | [src]

- `impl Hash for u8` | [src]

- `impl<Ret, A, B, C, D> Hash for extern "C" fn(A, B, C, D, ...) -> Ret` | [src]

- `impl<T> Hash for *const T where T: ?Sized,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H) -> Ret` | [src]

- `impl<T> Hash for [T; 26] where T: Hash,` | [src]

- `impl Hash for u64` | [src]

- `impl<Y, R> Hash for GeneratorState<Y, R> where R: Hash, Y: Hash,` | [src]

- `impl<Ret, A> Hash for unsafe extern "C" fn(A, ...) -> Ret` | [src]

- `impl Hash for i64` | [src]

- `impl<Ret, A, B, C> Hash for unsafe extern "C" fn(A, B, C, ...) -> Ret` | [src]

- `impl Hash for NonZeroU16` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret` | [src]

- `impl<Ret, A> Hash for unsafe extern "C" fn(A) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, ...) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I) -> Ret` | [src]

- `impl Hash for u16` | [src]

- `impl<Ret, A, B, C> Hash for extern "C" fn(A, B, C) -> Ret` | [src]

- `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 + ?Sized,` | [src]

- `impl Hash for NonZeroU64` | [src]

- `impl Hash for usize` | [src]

- `impl Hash for Pinned` | [src]

- `impl Hash for RangeFull` | [src]

- `impl<Ret, A, B, C, D, E> Hash for extern "C" fn(A, B, C, D, E, ...) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E> Hash for unsafe fn(A, B, C, D, E) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(A, B, C, D, E, F, ...) -> Ret` | [src]

- `impl Hash for Duration` | [src]

- `impl<T> Hash for [T; 25] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, J, ...) -> Ret` | [src]

- `impl<T> Hash for [T; 6] where T: Hash,` | [src]

- `impl<T> Hash for [T; 15] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(A, B, C, D) -> Ret` | [src]

- `impl<Idx> Hash for RangeInclusive<Idx> where Idx: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(A, B, C, D, E, F, G) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(A, B, C, D, E, ...) -> Ret` | [src]

- `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` | [src]

- `impl<Ret, A, B, C> Hash for unsafe fn(A, B, C) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(A, B, C, D, E, F, G, H, ...) -> Ret` | [src]

- `impl<T> Hash for Option<T> where T: Hash,` | [src]

- `impl Hash for Error` | [src]

- `impl Hash for i128` | [src]

- `impl<T> Hash for [T; 21] where T: Hash,` | [src]

- `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 + ?Sized,` | [src]

- `impl<Ret, A> Hash for extern "C" fn(A, ...) -> Ret` | [src]

- `impl<T> Hash for Wrapping<T> where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret` | [src]

- `impl<Ret, A, B, C, D> Hash for fn(A, B, C, D) -> Ret` | [src]

- `impl<T> Hash for [T; 13] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for fn(A, B, C, D, E, F, G, H, I) -> Ret` | [src]

- `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` | [src]

- `impl Hash for !` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe fn(A, B, C, D, E, F, G, H) -> Ret` | [src]

- `impl Hash for NonZeroUsize` | [src]

- `impl<Idx> Hash for RangeToInclusive<Idx> where Idx: Hash,` | [src]

- `impl<Idx> Hash for RangeFrom<Idx> where Idx: Hash,` | [src]

- `impl<T> Hash for [T; 24] where T: Hash,` | [src]

- `impl<T> Hash for [T; 7] where T: Hash,` | [src]

- `impl<T> Hash for [T; 4] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G> Hash for unsafe fn(A, B, C, D, E, F, G) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret` | [src]

- `impl<Ret, A> Hash for unsafe fn(A) -> Ret` | [src]

- `impl<Ret> Hash for fn() -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret` | [src]

- `impl<T> Hash for [T; 30] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(A, B, C, D, ...) -> Ret` | [src]

- `impl<A, B, C> Hash for (A, B, C) where A: Hash, B: Hash, C: Hash + ?Sized,` | [src]

- `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 + ?Sized,` | [src]

- `impl<T> Hash for [T; 29] where T: Hash,` | [src]

- `impl<T> Hash for Reverse<T> where T: Hash,` | [src]

- `impl<T> Hash for [T; 3] where T: Hash,` | [src]

- `impl<T> Hash for [T; 32] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, ...) -> Ret` | [src]

- `impl<Ret, A, B> Hash for unsafe extern "C" fn(A, B, ...) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I) -> Ret` | [src]

- `impl<Idx> Hash for Range<Idx> where Idx: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret` | [src]

- `impl<Ret, A, B, C> Hash for unsafe extern "C" fn(A, B, C) -> Ret` | [src]

- `impl Hash for i16` | [src]

- `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` | [src]

- `impl Hash for i8` | [src]

- `impl<T> Hash for [T; 11] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(A, B, C, D, E, F) -> Ret` | [src]

- `impl<Ret, A, B, C, D, E, F> Hash for unsafe fn(A, B, C, D, E, F) -> Ret` | [src]

- `impl<T> Hash for [T; 27] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(A, B, C, D, E, F) -> Ret` | [src]

- `impl<T> Hash for [T] where T: Hash,` | [src]

- `impl<A, B, C, D, E> Hash for (A, B, C, D, E) where A: Hash, B: Hash, C: Hash, D: Hash, E: Hash + ?Sized,` | [src]

- `impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(A, B, C, D, E, F, ...) -> Ret` | [src]

- `impl<T> Hash for NonNull<T> where T: ?Sized,` | [src]

- `impl<Idx> Hash for RangeTo<Idx> where Idx: Hash,` | [src]

- `impl<'a, T> Hash for &'a T where T: Hash + ?Sized,` | [src]

- `impl<Ret, A, B> Hash for fn(A, B) -> Ret` | [src]

- `impl Hash for isize` | [src]

- `impl<Ret> Hash for extern "C" fn() -> Ret` | [src]

- `impl<Ret, A, B, C> Hash for fn(A, B, C) -> Ret` | [src]

- `impl<T> Hash for [T; 28] where T: Hash,` | [src]

- `impl<T> Hash for ManuallyDrop<T> where T: Hash,` | [src]

- `impl<Ret, A, B, C, D> Hash for extern "C" fn(A, B, C, D) -> Ret` | [src]

- `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` | [src]

- `impl<T> Hash for Discriminant<T>` | [src]

- `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` | [src]

- `impl<T> Hash for [T; 1] where T: Hash,` | [src]

- `impl<T> Hash for [T; 22] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret` | [src]

- `impl<T> Hash for [T; 2] where T: Hash,` | [src]

- `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 + ?Sized,` | [src]

- `impl<T> Hash for [T; 16] where T: Hash,` | [src]

- `impl<T> Hash for Bound<T> where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret` | [src]

- `impl Hash for str` | [src]

- `impl<T> Hash for *mut T where T: ?Sized,` | [src]

- `impl Hash for char` | [src]

- `impl<T> Hash for [T; 10] where T: Hash,` | [src]

- `impl<T> Hash for [T; 14] where T: Hash,` | [src]

- `impl<T> Hash for Poll<T> where T: Hash,` | [src]

- `impl<Ret, A, B> Hash for extern "C" fn(A, B) -> Ret` | [src]

- `impl<T> Hash for [T; 9] where T: Hash,` | [src]

- `impl Hash for bool` | [src]

- `impl Hash for u128` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(A, B, C, D, E, F, G, H) -> Ret` | [src]

- `impl Hash for TypeId` | [src]

- `impl<T> Hash for PhantomData<T> where T: ?Sized,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L, ...) -> Ret` | [src]

- `impl<Ret, A, B, C, D> Hash for unsafe fn(A, B, C, D) -> Ret` | [src]

- `impl<T> Hash for [T; 17] where T: Hash,` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret` | [src]

- `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` | [src]

- `impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G) -> Ret` | [src]

- `impl<T> Hash for [T; 5] where T: Hash,` | [src]

- `impl Hash for NonZeroU32` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L, ...) -> Ret` | [src]

- `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` | [src]

- `impl<T> Hash for [T; 18] where T: Hash,` | [src]

- `impl<A, B> Hash for (A, B) where A: Hash, B: Hash + ?Sized,` | [src]

- `impl Hash for i32` | [src]

- `impl<T> Hash for [T; 8] where T: Hash,` | [src]

- `impl<Ret> Hash for unsafe fn() -> Ret` | [src]

- `impl<T, E> Hash for Result<T, E> where E: Hash, T: Hash,` | [src]

- `impl Hash for NonZeroU8` | [src]

- `impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret` | [src]

- `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 + ?Sized,` | [src]

- `impl<A, B, C, D> Hash for (A, B, C, D) where A: Hash, B: Hash, C: Hash, D: Hash + ?Sized,` | [src]

- `impl<Ret, A, B, C, D, E, F, G> Hash for fn(A, B, C, D, E, F, G) -> Ret` | [src]

- `impl Hash for Ordering` | [src]

- `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 + ?Sized,` | [src]

- `impl Hash for String` | [src]

- `impl<T> Hash for LinkedList<T> where T: Hash,` | [src]

- `impl<T> Hash for BTreeSet<T> where T: Hash,` | [src]

- `impl<T> Hash for Rc<T> where T: Hash + ?Sized,` | [src]

- `impl<K, V> Hash for BTreeMap<K, V> where K: Hash, V: Hash,` | [src]

- `impl<T> Hash for Vec<T> where T: Hash,` | [src]

- `impl<T> Hash for Box<T> where T: Hash + ?Sized,` | [src]

- `impl<'a, B> Hash for Cow<'a, B> where B: Hash + ToOwned + ?Sized,` | [src]

- `impl<T> Hash for Arc<T> where T: Hash + ?Sized,` | [src]

- `impl<A> Hash for VecDeque<A> where A: Hash,` | [src]

- `impl Hash for ThreadId` | [src]

- `impl Hash for CString` | [src]

- `impl Hash for CStr` | [src]

- `impl Hash for OsString` | [src]

- `impl Hash for OsStr` | [src]

- `impl Hash for FileType` | [src]

- `impl Hash for ErrorKind` | [src]

- `impl Hash for IpAddr` | [src]

- `impl Hash for Ipv6MulticastScope` | [src]

- `impl Hash for Ipv4Addr` | [src]

- `impl Hash for Ipv6Addr` | [src]

- `impl Hash for SocketAddr` | [src]

- `impl Hash for SocketAddrV4` | [src]

- `impl Hash for SocketAddrV6` | [src]

- `impl<'a> Hash for Prefix<'a>` | [src]

- `impl<'a> Hash for PrefixComponent<'a>` | [src]

- `impl<'a> Hash for Component<'a>` | [src]

- `impl Hash for PathBuf` | [src]

- `impl Hash for Path` | [src]

- `impl Hash for Instant` | [src]

- `impl Hash for SystemTime` | [src]

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