tuple - Rust (original) (raw)
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:
‘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)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');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");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);Homogeneous tuples can be created from arrays of appropriate length:
let array: [u32; 3] = [1, 2, 3];
let tuple: (u32, u32, u32) = array.into();This trait is implemented for tuples up to twelve items long.
This trait is implemented for tuples up to twelve items long.
Extends a collection with the contents of an iterator. Read more
🔬This is a nightly-only experimental API. (extend_one #72631)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
Extends a collection with the contents of an iterator. Read more
🔬This is a nightly-only experimental API. (extend_one #72631)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
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]);🔬This is a nightly-only experimental API. (extend_one #72631)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
Extends a collection with the contents of an iterator. Read more
🔬This is a nightly-only experimental API. (extend_one #72631)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.
Extends a collection with the contents of an iterator. Read more
🔬This is a nightly-only experimental API. (extend_one #72631)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
This trait is implemented for tuples up to twelve items long.
This trait is implemented for tuples up to twelve items long.
This trait is implemented for tuples up to twelve items long.
This method tests for self and other values to be equal, and is used by ==.
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
This trait is implemented for tuples up to twelve items long.
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >=operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
The output type returned by methods.
🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
🔬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.
🔬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.
🔬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.
🔬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.
Implements substring slicing for arbitrary bounds.
Returns a slice of the given string bounded by the byte indices provided by each bound.
This operation is O(1).
Panics
Panics if begin or end (if it exists and once adjusted for inclusion/exclusion) does not point to the starting byte offset of a character (as defined by is_char_boundary), if begin > end, or ifend > len.
The output type returned by methods.
🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
🔬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.
🔬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.
🔬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.
🔬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.
Returned iterator over socket addresses which this type may correspond to.
Returned iterator over socket addresses which this type may correspond to.
Returned iterator over socket addresses which this type may correspond to.
Returned iterator over socket addresses which this type may correspond to.
Returned iterator over socket addresses which this type may correspond to.
This trait is implemented for tuples up to twelve items long.
This trait is implemented for tuples up to twelve items long.
This trait is implemented for tuples up to twelve items long.
This trait is implemented for tuples up to twelve items long.
Returns the argument unchanged.
Calls U::from(self).
That is, this conversion is whatever the implementation of[From](convert/trait.From.html "trait std::convert::From")<T> for U chooses to do.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.