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');
Run‘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)
RunTuples 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');
RunThe 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");
RunTuples 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);
RunTrait Implementations
sourceimpl<T: Clone> Clone for (T₁, T₂, …, Tₙ)
impl<T: Clone> Clone for (T₁, T₂, …, Tₙ)
This trait is implemented on arbitrary-length tuples.
sourceimpl<T: Debug> Debug for (T₁, T₂, …, Tₙ) where
T: ?Sized,
impl<T: Debug> Debug for (T₁, T₂, …, Tₙ) where
T: ?Sized,
This trait is implemented for tuples up to twelve items long.
sourceimpl<T: Default> Default for (T₁, T₂, …, Tₙ)
impl<T: Default> Default for (T₁, T₂, …, Tₙ)
This trait is implemented for tuples up to twelve items long.
1.56.0 · sourceimpl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB) where
ExtendA: Extend<A>,
ExtendB: Extend<B>,
impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB) where
ExtendA: Extend<A>,
ExtendB: Extend<B>,
sourcefn extend<T: IntoIterator<Item = (A, B)>>(&mut self, into_iter: T)
fn extend<T: IntoIterator<Item = (A, B)>>(&mut self, into_iter: T)
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]);
Runsourcefn extend_reserve(&mut self, additional: usize)
fn extend_reserve(&mut self, additional: usize)
Reserves capacity in a collection for the given number of additional elements. Read more
sourceimpl<T: Hash> Hash for (T₁, T₂, …, Tₙ) where
T: ?Sized,
impl<T: Hash> Hash for (T₁, T₂, …, Tₙ) where
T: ?Sized,
This trait is implemented for tuples up to twelve items long.
sourceimpl<T: Ord> Ord for (T₁, T₂, …, Tₙ) where
T: ?Sized,
impl<T: Ord> Ord for (T₁, T₂, …, Tₙ) where
T: ?Sized,
This trait is implemented for tuples up to twelve items long.
sourceimpl<T: PartialEq> PartialEq<(T,)> for (T₁, T₂, …, Tₙ) where
T: ?Sized,
impl<T: PartialEq> PartialEq<(T,)> for (T₁, T₂, …, Tₙ) where
T: ?Sized,
This trait is implemented for tuples up to twelve items long.
sourceimpl<T: PartialOrd + PartialEq> PartialOrd<(T,)> for (T₁, T₂, …, Tₙ) where
T: ?Sized,
impl<T: PartialOrd + PartialEq> PartialOrd<(T,)> for (T₁, T₂, …, Tₙ) where
T: ?Sized,
This trait is implemented for tuples up to twelve items long.
sourcefn partial_cmp(&self, other: &(T,)) -> Option<Ordering>
fn partial_cmp(&self, other: &(T,)) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
sourcefn lt(&self, other: &(T,)) -> bool
fn lt(&self, other: &(T,)) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
sourcefn le(&self, other: &(T,)) -> bool
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
1.28.0 · sourceimpl<T> RangeBounds<T> for (Bound<T>, Bound<T>)
impl<T> RangeBounds<T> for (Bound<T>, Bound<T>)
1.53.0 · sourceimpl<T> SliceIndex<[T]> for (Bound<usize>, Bound<usize>)
impl<T> SliceIndex<[T]> for (Bound<usize>, Bound<usize>)
sourcefn get(self, slice: &[T]) -> Option<&Self::Output>
fn get(self, slice: &[T]) -> Option<&Self::Output>
slice_index_methods
)Returns a shared reference to the output at this location, if in bounds. Read more
sourcefn get_mut(self, slice: &mut [T]) -> Option<&mut Self::Output>
fn get_mut(self, slice: &mut [T]) -> Option<&mut Self::Output>
slice_index_methods
)Returns a mutable reference to the output at this location, if in bounds. Read more
sourceunsafe fn get_unchecked(self, slice: *const [T]) -> *const Self::Output
unsafe fn get_unchecked(self, slice: *const [T]) -> *const Self::Output
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. Read more
sourceunsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut Self::Output
unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut Self::Output
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. Read more
impl<T: Copy> Copy for (T₁, T₂, …, Tₙ)
This trait is implemented on arbitrary-length tuples.
impl<T: Eq> Eq for (T₁, T₂, …, Tₙ) where
T: ?Sized,
This trait is implemented for tuples up to twelve items long.
Auto Trait Implementations
impl<T> RefUnwindSafe for (T₁, T₂, …, Tₙ) where
T: RefUnwindSafe,
impl<T> Send for (T₁, T₂, …, Tₙ) where
T: Send,
impl<T> Sync for (T₁, T₂, …, Tₙ) where
T: Sync,
impl<T> Unpin for (T₁, T₂, …, Tₙ) where
T: Unpin,
impl<T> UnwindSafe for (T₁, T₂, …, Tₙ) where
T: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more