Primitive Type tuple

1.0.0 ·
Expand description

A finite heterogeneous sequence, `(T, U, ..)`.

Let’s cover each of those in turn:

Tuples are finite. In other words, a tuple has a length. Here’s a tuple of length `3`:

``("hello", 5, 'c');``
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‘Length’ is also sometimes called ‘arity’ here; each tuple of a different length is a different, distinct type.

Tuples are heterogeneous. This means that each element of the tuple can have a different type. In that tuple above, it has the type:

``(&'static str, i32, char)``
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Tuples are a sequence. This means that they can be accessed by position; this is called ‘tuple indexing’, and it looks like this:

``````let tuple = ("hello", 5, 'c');

assert_eq!(tuple.0, "hello");
assert_eq!(tuple.1, 5);
assert_eq!(tuple.2, 'c');``````
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The sequential nature of the tuple applies to its implementations of various traits. For example, in `PartialOrd` and `Ord`, the elements are compared sequentially until the first non-equal set is found.

For more about tuples, see the book.

Trait implementations

In this documentation the shorthand `(T₁, T₂, …, Tₙ)` is used to represent tuples of varying length. When that is used, any trait bound expressed on `T` applies to each element of the tuple independently. Note that this is a convenience notation to avoid repetitive documentation, not valid Rust syntax.

Due to a temporary restriction in Rust’s type system, the following traits are only implemented on tuples of arity 12 or less. In the future, this may change:

The following traits are implemented for tuples of any length. These traits have implementations that are automatically generated by the compiler, so are not limited by missing language features.

Examples

Basic usage:

``````let tuple = ("hello", 5, 'c');

assert_eq!(tuple.0, "hello");``````
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Tuples are often used as a return type when you want to return more than one value:

``````fn calculate_point() -> (i32, i32) {
// Don't do a calculation, that's not the point of the example
(4, 5)
}

let point = calculate_point();

assert_eq!(point.0, 4);
assert_eq!(point.1, 5);

// Combining this with patterns can be nicer.

let (x, y) = calculate_point();

assert_eq!(x, 4);
assert_eq!(y, 5);``````
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Trait Implementations§

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impl<T: Clone> Clone for (T₁, T₂, …, Tₙ)

This trait is implemented on arbitrary-length tuples.

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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impl<T> Debug for (T₁, T₂, …, Tₙ)where T: Debug + ?Sized,

This trait is implemented for tuples up to twelve items long.

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
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impl<T> Default for (T₁, T₂, …, Tₙ)where T: Default,

This trait is implemented for tuples up to twelve items long.

const: unstable · source§

fn default() -> (T,)

Returns the “default value” for a type. Read more
1.2.0 · source§

impl<'a, K, V, A> Extend<(&'a K, &'a V)> for BTreeMap<K, V, A>where K: Ord + Copy, V: Copy, A: Allocator + Clone,

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fn extend<I>(&mut self, iter: I)where I: IntoIterator<Item = (&'a K, &'a V)>,

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, _: (&'a K, &'a V))

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
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🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
1.4.0 · source§

impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S>where K: Eq + Hash + Copy, V: Copy, S: BuildHasher,

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fn extend<T: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, (k, v): (&'a K, &'a V))

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
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🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
1.56.0 · source§

impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB)where ExtendA: Extend<A>, ExtendB: Extend<B>,

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fn extend<T>(&mut self, into_iter: T)where T: IntoIterator<Item = (A, B)>,

Allows to `extend` a tuple of collections that also implement `Extend`.

See also: `Iterator::unzip`

Examples
``````let mut tuple = (vec![0], vec![1]);
tuple.extend([(2, 3), (4, 5), (6, 7)]);
assert_eq!(tuple.0, [0, 2, 4, 6]);
assert_eq!(tuple.1, [1, 3, 5, 7]);

// also allows for arbitrarily nested tuples as elements
let mut nested_tuple = (vec![1], (vec![2], vec![3]));
nested_tuple.extend([(4, (5, 6)), (7, (8, 9))]);

let (a, (b, c)) = nested_tuple;
assert_eq!(a, [1, 4, 7]);
assert_eq!(b, [2, 5, 8]);
assert_eq!(c, [3, 6, 9]);``````
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fn extend_one(&mut self, item: (A, B))

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
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🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<K, V, A> Extend<(K, V)> for BTreeMap<K, V, A>where K: Ord, A: Allocator + Clone,

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fn extend<T>(&mut self, iter: T)where T: IntoIterator<Item = (K, V)>,

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, _: (K, V))

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
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🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S>where K: Eq + Hash, S: BuildHasher,

Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.

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fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, (k, v): (K, V))

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
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🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
1.17.0 · source§

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fn from(pieces: (I, u16)) -> SocketAddr

Converts a tuple struct (Into<`IpAddr`>, `u16`) into a `SocketAddr`.

This conversion creates a `SocketAddr::V4` for an `IpAddr::V4` and creates a `SocketAddr::V6` for an `IpAddr::V6`.

`u16` is treated as port of the newly created `SocketAddr`.

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impl<K, V> FromIterator<(K, V)> for BTreeMap<K, V, Global>where K: Ord,

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fn from_iter<T>(iter: T) -> BTreeMap<K, V, Global>where T: IntoIterator<Item = (K, V)>,

Creates a value from an iterator. Read more
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impl<K, V, S> FromIterator<(K, V)> for HashMap<K, V, S>where K: Eq + Hash, S: BuildHasher + Default,

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fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> HashMap<K, V, S>

Creates a value from an iterator. Read more
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impl<T> Hash for (T₁, T₂, …, Tₙ)where T: Hash + ?Sized,

This trait is implemented for tuples up to twelve items long.

const: unstable · source§

fn hash<S>(&self, state: &mut S)where S: Hasher,

Feeds this value into the given `Hasher`. Read more
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impl<T> Ord for (T₁, T₂, …, Tₙ)where T: Ord + ?Sized,

This trait is implemented for tuples up to twelve items long.

const: unstable · source§

fn cmp(&self, other: &(T,)) -> Ordering

This method returns an `Ordering` between `self` and `other`. Read more
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impl<T> PartialEq<(T,)> for (T₁, T₂, …, Tₙ)where T: PartialEq<T> + ?Sized,

This trait is implemented for tuples up to twelve items long.

const: unstable · source§

fn eq(&self, other: &(T,)) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
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fn ne(&self, other: &(T,)) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<T> PartialOrd<(T,)> for (T₁, T₂, …, Tₙ)where T: PartialOrd<T> + PartialEq<T> + ?Sized,

This trait is implemented for tuples up to twelve items long.

const: unstable · source§

fn partial_cmp(&self, other: &(T,)) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
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fn lt(&self, other: &(T,)) -> bool

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more
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fn le(&self, other: &(T,)) -> bool

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
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fn ge(&self, other: &(T,)) -> bool

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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fn gt(&self, other: &(T,)) -> bool

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
1.28.0 (const: unstable) · source§

impl<'a, T> RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>)where T: 'a + ?Sized,

const: unstable · source§

fn start_bound(&self) -> Bound<&T>

const: unstable · source§

1.35.0 · source§

fn contains<U>(&self, item: &U) -> boolwhere T: PartialOrd<U>, U: PartialOrd<T> + ?Sized,

Returns `true` if `item` is contained in the range. Read more
1.28.0 (const: unstable) · source§

impl<T> RangeBounds<T> for (Bound<T>, Bound<T>)

const: unstable · source§

fn start_bound(&self) -> Bound<&T>

const: unstable · source§

1.35.0 · source§

fn contains<U>(&self, item: &U) -> boolwhere T: PartialOrd<U>, U: PartialOrd<T> + ?Sized,

Returns `true` if `item` is contained in the range. Read more
1.53.0 · source§

impl<T> SliceIndex<[T]> for (Bound<usize>, Bound<usize>)

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type Output = [T]

The output type returned by methods.
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fn get( self, slice: &[T] ) -> Option<&<(Bound<usize>, Bound<usize>) as SliceIndex<[T]>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
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fn get_mut( self, slice: &mut [T] ) -> Option<&mut <(Bound<usize>, Bound<usize>) as SliceIndex<[T]>>::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
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unsafe fn get_unchecked( self, slice: *const [T] ) -> *const <(Bound<usize>, Bound<usize>) as SliceIndex<[T]>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
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unsafe fn get_unchecked_mut( self, slice: *mut [T] ) -> *mut <(Bound<usize>, Bound<usize>) as SliceIndex<[T]>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting reference is not used.
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fn index( self, slice: &[T] ) -> &<(Bound<usize>, Bound<usize>) as SliceIndex<[T]>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
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fn index_mut( self, slice: &mut [T] ) -> &mut <(Bound<usize>, Bound<usize>) as SliceIndex<[T]>>::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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Returned iterator over socket addresses which this type may correspond to.
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Converts this object to an iterator of resolved `SocketAddr`s. Read more
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Returned iterator over socket addresses which this type may correspond to.
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Converts this object to an iterator of resolved `SocketAddr`s. Read more
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Returned iterator over socket addresses which this type may correspond to.
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Converts this object to an iterator of resolved `SocketAddr`s. Read more
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Returned iterator over socket addresses which this type may correspond to.
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Converts this object to an iterator of resolved `SocketAddr`s. Read more
1.46.0 · source§

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Returned iterator over socket addresses which this type may correspond to.
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Converts this object to an iterator of resolved `SocketAddr`s. Read more
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impl<T: Copy> Copy for (T₁, T₂, …, Tₙ)

This trait is implemented on arbitrary-length tuples.

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impl<T> Eq for (T₁, T₂, …, Tₙ)where T: Eq + ?Sized,

This trait is implemented for tuples up to twelve items long.

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Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.