#[lang = "ord"]
pub trait Ord: Eq + PartialOrd<Self> {
fn cmp(&self, other: &Self) -> Ordering;
fn max(self, other: Self) -> Self { ... }
fn min(self, other: Self) -> Self { ... }
}
Trait for types that form a total order.
An order is a total order if it is (for all a
, b
and c
):
- total and antisymmetric: exactly one of
a < b
, a == b
or a > b
is true; and
- transitive,
a < b
and b < c
implies a < c
. The same must hold for both ==
and >
.
This trait can be used with #[derive]
. When derive
d on structs, it will produce a
lexicographic ordering based on the top-to-bottom declaration order of the struct's members.
When derive
d on enums, variants are ordered by their top-to-bottom declaration order.
Ord
requires that the type also be PartialOrd
and Eq
(which requires PartialEq
).
Then you must define an implementation for cmp()
. You may find it useful to use
cmp()
on your type's fields.
Implementations of PartialEq
, PartialOrd
, and Ord
must agree with each other. It's
easy to accidentally make them disagree by deriving some of the traits and manually
implementing others.
Here's an example where you want to sort people by height only, disregarding id
and name
:
use std::cmp::Ordering;
#[derive(Eq)]
struct Person {
id: u32,
name: String,
height: u32,
}
impl Ord for Person {
fn cmp(&self, other: &Person) -> Ordering {
self.height.cmp(&other.height)
}
}
impl PartialOrd for Person {
fn partial_cmp(&self, other: &Person) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl PartialEq for Person {
fn eq(&self, other: &Person) -> bool {
self.height == other.height
}
}
fn cmp(&self, other: &Self) -> Ordering
This method returns an Ordering
between self
and other
.
By convention, self.cmp(&other)
returns the ordering matching the expression
self <operator> other
if true.
use std::cmp::Ordering;
assert_eq!(5.cmp(&10), Ordering::Less);
assert_eq!(10.cmp(&5), Ordering::Greater);
assert_eq!(5.cmp(&5), Ordering::Equal);
fn max(self, other: Self) -> Self
1.21.0
Compares and returns the maximum of two values.
Returns the second argument if the comparison determines them to be equal.
assert_eq!(2, 1.max(2));
assert_eq!(2, 2.max(2));
fn min(self, other: Self) -> Self
1.21.0
Compares and returns the minimum of two values.
Returns the first argument if the comparison determines them to be equal.
assert_eq!(1, 1.min(2));
assert_eq!(2, 2.min(2));
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
Panics if the value in either RefCell
is currently borrowed.
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
fn max(self, other: Self) -> Self | 1.21.0 [src] |
fn min(self, other: Self) -> Self | 1.21.0 [src] |
impl<Ret, A, B, C, D, E> Ord for unsafe fn(A, B, C, D, E) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret | |
impl<T> Ord for [T; 7] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G> Ord for extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret | |
impl<T> Ord for [T; 29] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, ...) -> Ret | |
impl<T> Ord for [T; 4] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G, H> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H) -> Ret | |
impl<A, B, C> Ord for (A, B, C) where A: Ord, B: Ord, C: Ord + ?Sized, | |
impl<Ret, A, B, C, D, E, F, G, H, I> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for unsafe fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret | |
impl<A, B, C, D, E, F, G, H, I, J> Ord for (A, B, C, D, E, F, G, H, I, J) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord, J: Ord + ?Sized, | |
impl<T> Ord for [T; 18] where T: Ord, | |
impl<Ret, A, B, C, D, E> Ord for unsafe extern "C" fn(A, B, C, D, E, ...) -> Ret | |
impl<Ret, A, B, C> Ord for unsafe extern "C" fn(A, B, C) -> Ret | |
impl<Ret, A, B, C, D, E, F, G> Ord for fn(A, B, C, D, E, F, G) -> Ret | |
impl<Ret, A, B, C, D, E, F, G> Ord for extern "C" fn(A, B, C, D, E, F, G) -> Ret | |
impl<Ret, A, B, C, D> Ord for fn(A, B, C, D) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, ...) -> Ret | |
impl<A, B> Ord for (A, B) where A: Ord, B: Ord + ?Sized, | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret | |
impl<Ret, A, B> Ord for extern "C" fn(A, B, ...) -> Ret | |
impl<Ret, A> Ord for unsafe extern "C" fn(A) -> Ret | |
impl<T> Ord for [T; 17] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G, H> Ord for fn(A, B, C, D, E, F, G, H) -> Ret | |
impl<T> Ord for [T; 2] where T: Ord, | |
impl<Ret, A, B, C> Ord for extern "C" fn(A, B, C, ...) -> Ret | |
impl<Ret, A, B, C, D> Ord for extern "C" fn(A, B, C, D) -> Ret | |
impl<Ret, A, B, C, D> Ord for unsafe fn(A, B, C, D) -> Ret | |
impl<T> Ord for [T; 19] where T: Ord, | |
impl<Ret> Ord for unsafe fn() -> Ret | |
impl<Ret, A, B, C> Ord for unsafe extern "C" fn(A, B, C, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for extern "C" 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> Ord for fn(A, B, C, D, E, F, G, H, I, J) -> Ret | |
impl<Ret, A, B, C, D, E> Ord for fn(A, B, C, D, E) -> Ret | |
impl<T> Ord for [T; 23] where T: Ord, | |
impl<Ret, A, B, C, D, E> Ord for extern "C" fn(A, B, C, D, E, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I> Ord for fn(A, B, C, D, E, F, G, H, I) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret | |
impl<A, B, C, D> Ord for (A, B, C, D) where A: Ord, B: Ord, C: Ord, D: Ord + ?Sized, | |
impl<Ret, A> Ord for unsafe extern "C" fn(A, ...) -> Ret | |
impl<T> Ord for [T; 9] where T: Ord, | |
impl<T> Ord for [T; 15] where T: Ord, | |
impl<'a, A> Ord for &'a A where A: Ord + ?Sized, | |
impl<Ret, A, B, C> Ord for extern "C" fn(A, B, C) -> Ret | |
impl<A, B, C, D, E, F, G, H, I> Ord for (A, B, C, D, E, F, G, H, I) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord + ?Sized, | |
impl<T> Ord for [T; 10] where T: Ord, | |
impl<T> Ord for [T; 25] where T: Ord, | |
impl<T> Ord for [T; 30] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I> Ord for unsafe fn(A, B, C, D, E, F, G, H, I) -> Ret | |
impl<Ret, A> Ord for fn(A) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret | |
impl<A, B, C, D, E, F, G, H> Ord for (A, B, C, D, E, F, G, H) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord + ?Sized, | |
impl<Ret, A, B, C, D> Ord for extern "C" fn(A, B, C, D, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F> Ord for extern "C" fn(A, B, C, D, E, F, ...) -> Ret | |
impl<Ret, A, B, C, D, E> Ord for unsafe extern "C" fn(A, B, C, D, E) -> Ret | |
impl<T> Ord for [T; 28] where T: Ord, | |
impl<T> Ord for [T; 22] where T: Ord, | |
impl<T> Ord for *mut T where T: ?Sized, | |
impl<A, B, C, D, E> Ord for (A, B, C, D, E) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord + ?Sized, | |
impl<Ret, A> Ord for unsafe fn(A) -> Ret | |
impl<Ret> Ord for unsafe extern "C" fn() -> Ret | |
impl<Ret, A> Ord for extern "C" fn(A, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret | |
impl<T> Ord for [T; 21] where T: Ord, | |
impl<T> Ord for [T; 16] where T: Ord, | |
impl<Ret, A, B, C, D> Ord for unsafe extern "C" fn(A, B, C, D) -> Ret | |
impl<T> Ord for [T; 14] where T: Ord, | |
impl<Ret, A, B, C, D> Ord for unsafe extern "C" fn(A, B, C, D, ...) -> Ret | |
impl<T> Ord for [T] where T: Ord, | |
impl<A, B, C, D, E, F> Ord for (A, B, C, D, E, F) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord + ?Sized, | |
impl<T> Ord for [T; 20] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G, H> Ord for extern "C" fn(A, B, C, D, E, F, G, H, ...) -> Ret | |
impl<A, B, C, D, E, F, G, H, I, J, K> Ord for (A, B, C, D, E, F, G, H, I, J, K) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord, J: Ord, K: Ord + ?Sized, | |
impl<T> Ord for [T; 11] where T: Ord, | |
impl<T> Ord for [T; 12] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret | |
impl<Ret, A, B> Ord for fn(A, B) -> Ret | |
impl<T> Ord for [T; 6] where T: Ord, | |
impl<'a, A> Ord for &'a mut A where A: Ord + ?Sized, | |
impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, J, ...) -> Ret | |
impl<Ret, A, B, C> Ord for unsafe fn(A, B, C) -> Ret | |
impl<Ret> Ord for fn() -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for unsafe fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret | |
impl<T> Ord for [T; 0] where T: Ord, | |
impl<Ret, A, B, C, D, E> Ord for extern "C" fn(A, B, C, D, E) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, ...) -> Ret | |
impl<T> Ord for [T; 5] where T: Ord, | |
impl<T> Ord for [T; 8] where T: Ord, | |
impl<Ret, A, B, C, D, E, F> Ord for fn(A, B, C, D, E, F) -> Ret | |
impl<Ret, A, B> Ord for unsafe extern "C" fn(A, B, ...) -> Ret | |
impl<Ret, A, B> Ord for extern "C" fn(A, B) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, ...) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H> Ord for extern "C" fn(A, B, C, D, E, F, G, H) -> Ret | |
impl<A, B, C, D, E, F, G> Ord for (A, B, C, D, E, F, G) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord + ?Sized, | |
impl<Ret, A, B, C, D, E, F, G> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G) -> Ret | |
impl<T> Ord for [T; 24] where T: Ord, | |
impl<Ret, A, B, C, D, E, F> Ord for unsafe extern "C" fn(A, B, C, D, E, F, ...) -> Ret | |
impl<Ret, A, B> Ord for unsafe extern "C" fn(A, B) -> Ret | |
impl<T> Ord for *const T where T: ?Sized, | |
impl<T> Ord for [T; 27] where T: Ord, | |
impl<T> Ord for [T; 3] where T: Ord, | |
impl<Ret, A, B, C, D, E, F> Ord for extern "C" fn(A, B, C, D, E, F) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret | |
impl<A, B, C, D, E, F, G, H, I, J, K, L> Ord for (A, B, C, D, E, F, G, H, I, J, K, L) where A: Ord, B: Ord, C: Ord, D: Ord, E: Ord, F: Ord, G: Ord, H: Ord, I: Ord, J: Ord, K: Ord, L: Ord + ?Sized, | |
impl<Ret, A, B, C, D, E, F> Ord for unsafe fn(A, B, C, D, E, F) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Ord for fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret | |
impl<Ret, A, B, C> Ord for fn(A, B, C) -> Ret | |
impl<T> Ord for [T; 26] where T: Ord, | |
impl<Ret, A, B, C, D, E, F, G> Ord for unsafe fn(A, B, C, D, E, F, G) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H> Ord for unsafe fn(A, B, C, D, E, F, G, H) -> Ret | |
impl<Ret, A, B, C, D, E, F> Ord for unsafe extern "C" fn(A, B, C, D, E, F) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Ord for unsafe extern "C" 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> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L, ...) -> Ret | |
impl<Ret, A> Ord for extern "C" fn(A) -> Ret | |
impl<Ret, A, B, C, D, E, F, G, H, I, J> Ord for unsafe fn(A, B, C, D, E, F, G, H, I, J) -> Ret | |
impl<Ret, A, B> Ord for unsafe fn(A, B) -> Ret | |
impl<A> Ord for (A,) where A: Ord + ?Sized, | |
impl<T> Ord for [T; 32] where T: Ord, | |
impl<T> Ord for [T; 31] where T: Ord, | |
impl<T> Ord for [T; 13] where T: Ord, | |
impl<T> Ord for [T; 1] where T: Ord, | |
impl<Ret> Ord for extern "C" fn() -> Ret | |