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):
a < b, a == b or a > b is true; anda < b and b < c implies a < c. The same must hold for both == and >.This trait can be used with #[derive]. When derived on structs, it will produce a lexicographic ordering based on the top-to-bottom declaration order of the struct's members. When derived on enums, variants are ordered by their top-to-bottom declaration order.
Ord?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) -> OrderingThis 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) -> SelfCompares 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) -> SelfCompares 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));
impl<T> Ord for NonZero<T> where
T: Zeroable + Ord,
[src]
fn cmp(&self, __arg_0: &NonZero<T>) -> Ordering
[src]
fn max(self, other: Self) -> Self
fn min(self, other: Self) -> Self
impl<T> Ord for Arc<T> where
T: Ord + ?Sized,
impl<A> Ord for VecDeque<A> where
A: Ord,
impl<K, V> Ord for BTreeMap<K, V> where
K: Ord,
V: Ord,
impl<T> Ord for Rc<T> where
T: Ord + ?Sized,
impl<T> Ord for LinkedList<T> where
T: Ord,
impl Ord for String
impl<T> Ord for Vec<T> where
T: Ord,
impl<T> Ord for Box<T> where
T: Ord + ?Sized,
impl<T> Ord for BTreeSet<T> where
T: Ord,
impl<'a, B> Ord for Cow<'a, B> where
B: Ord + ToOwned + ?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<T> Ord for [T; 12] where
T: Ord,
impl<Ret, A, B> Ord for unsafe extern "C" fn(A, B) -> 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> Ord for extern "C" fn(A, B, C, D, ...) -> Ret
impl Ord for u64
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<Ret, A, B, C> Ord for extern "C" fn(A, B, C) -> 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<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, 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, H> Ord for unsafe extern "C" fn(A, B, C, D, E, F, G, H) -> Ret
impl<T> Ord for [T; 2] where
T: Ord,
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, 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> Ord for unsafe extern "C" fn(A) -> Ret
impl<Ret, A> Ord for extern "C" fn(A, ...) -> Ret
impl<T> Ord for [T; 10] where
T: Ord,
impl Ord for usize
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, J> Ord for fn(A, B, C, D, E, F, G, H, I, J) -> Ret
impl<Ret> Ord for unsafe fn() -> Ret
impl Ord for isize
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, D, E, F> Ord for unsafe extern "C" fn(A, B, C, D, E, F) -> Ret
impl<Ret, A, B> Ord for unsafe fn(A, B) -> Ret
impl<T> Ord for [T; 25] where
T: Ord,
impl<Y, R> Ord for GeneratorState<Y, R> where
R: Ord,
Y: Ord,
impl<Ret, A, B, C, D> Ord for unsafe extern "C" fn(A, B, C, D, ...) -> Ret
impl Ord for i128
impl<T> Ord for [T; 32] where
T: Ord,
impl<Ret> Ord for unsafe extern "C" fn() -> 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 Ord for str
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<T> Ord for [T; 5] where
T: Ord,
impl Ord for bool
impl Ord for !impl<'a, A> Ord for &'a mut A where
A: Ord + ?Sized,
impl<Ret, A, B> Ord for extern "C" fn(A, B) -> 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<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<T> Ord for [T; 15] 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; 16] where
T: Ord,
impl<Ret, A, B, C, D, E> Ord for unsafe extern "C" fn(A, B, C, D, E, ...) -> Ret
impl<T> Ord for Option<T> where
T: Ord,
impl<T> Ord for [T; 27] 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<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<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<T> Ord for [T; 22] where
T: Ord,
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 Ord for Infallible
impl<T> Ord for [T; 18] where
T: Ord,
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, D, E, F, G, H> Ord for unsafe fn(A, B, C, D, E, F, G, H) -> Ret
impl<T> Ord for [T; 23] where
T: Ord,
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> Ord for fn(A, B, C, D, E, F, G, H) -> Ret
impl<Ret, A, B, C> Ord for unsafe extern "C" fn(A, B, C) -> Ret
impl Ord for ()
impl<T> Ord for [T; 6] where
T: Ord,
impl<T> Ord for *mut T where
T: ?Sized,
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> Ord for fn(A) -> Ret
impl<Ret, A, B, C> Ord for fn(A, B, C) -> 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, 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, 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 Ord for u8
impl<T> Ord for ManuallyDrop<T> where
T: Ord,
impl<Ret, A, B> Ord for unsafe extern "C" fn(A, B, ...) -> Ret
impl<Ret, A> Ord for unsafe fn(A) -> Ret
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> Ord for extern "C" fn(A, B, C, D) -> Ret
impl<T> Ord for [T; 17] where
T: Ord,
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; 14] where
T: Ord,
impl<Ret, A, B, C, D> Ord for unsafe fn(A, B, C, D) -> Ret
impl Ord for i64
impl<T> Ord for [T] where
T: Ord,
impl<T> Ord for [T; 31] where
T: Ord,
impl Ord for i8
impl<Ret, A, B, C, D, E> Ord for fn(A, B, C, D, E) -> 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<T> Ord for [T; 8] where
T: Ord,
impl<'a, A> Ord for &'a A where
A: Ord + ?Sized,
impl<T> Ord for [T; 29] where
T: Ord,
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<Ret, A, B, C, D, E, F> Ord for fn(A, B, C, D, E, F) -> Ret
impl<T> Ord for [T; 24] where
T: Ord,
impl Ord for i32
impl<Ret> Ord for fn() -> Ret
impl Ord for i16
impl<T> Ord for [T; 9] where
T: Ord,
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; 20] where
T: Ord,
impl<T> Ord for Reverse<T> 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 fn(A, B, C) -> Ret
impl<T> Ord for [T; 30] where
T: Ord,
impl<Ret, A, B, C, D, E> Ord for unsafe fn(A, B, C, D, E) -> Ret
impl<Ret, A, B> Ord for extern "C" fn(A, B, ...) -> Ret
impl<T> Ord for Wrapping<T> where
T: Ord,
impl Ord for Ordering
impl Ord for u32
impl<T> Ord for [T; 0] 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 Ord for NoneError
impl<Ret, A, B, C, D, E, F, G> Ord for fn(A, B, C, D, E, F, G) -> Ret
impl<T> Ord for [T; 26] where
T: Ord,
impl<T> Ord for PhantomData<T> where
T: ?Sized,
impl<Ret, A, B, C, D> Ord for fn(A, B, C, D) -> Ret
impl<Ret, A, B, C> Ord for unsafe extern "C" fn(A, B, C, ...) -> Ret
impl<A, B, C, D> Ord for (A, B, C, D) where
A: Ord,
B: Ord,
C: Ord,
D: Ord + ?Sized,
impl<T> Ord for *const T where
T: ?Sized,
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> Ord for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> 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 Ord for TypeId
impl<Ret, A, B, C> Ord for extern "C" fn(A, B, C, ...) -> Ret
impl<T> Ord for [T; 4] 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 Cell<T> where
T: Copy + Ord,
impl<A, B, C> Ord for (A, B, C) where
A: Ord,
B: Ord,
C: Ord + ?Sized,
impl<Ret, A, B> Ord for fn(A, B) -> Ret
impl<T> Ord for RefCell<T> where
T: Ord + ?Sized,
impl<Ret, A, B, C, D, E> Ord for extern "C" fn(A, B, C, D, E, ...) -> Ret
impl Ord for Error
impl Ord for u128
impl<T> Ord for [T; 28] 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<T> Ord for [T; 3] where
T: Ord,
impl<Ret, A, B, C, D, E, F> Ord for unsafe fn(A, B, C, D, E, F) -> Ret
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<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, E> Ord for Result<T, E> where
E: Ord,
T: Ord,
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; 19] where
T: Ord,
impl<T> Ord for [T; 13] 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<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<T> Ord for [T; 1] where
T: Ord,
impl Ord for char
impl<Ret, A, B, C, D, E, F, G> Ord for unsafe fn(A, B, C, D, E, F, G) -> Ret
impl<Ret, A> Ord for extern "C" fn(A) -> Ret
impl<T> Ord for [T; 7] 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> Ord for unsafe extern "C" fn(A, ...) -> Ret
impl<T> Ord for [T; 21] where
T: Ord,
impl Ord for u16
impl<Ret> Ord for extern "C" fn() -> Ret
impl<T> Ord for [T; 11] where
T: Ord,
impl<A, B> Ord for (A, B) where
A: Ord,
B: Ord + ?Sized,
impl<A> Ord for (A,) where
A: Ord + ?Sized,
impl<Ret, A, B, C, D, E, F, G> Ord for extern "C" fn(A, B, C, D, E, F, G) -> Ret
impl Ord for UnicodeVersion
impl Ord for CString
impl Ord for CStr
impl Ord for OsString
impl Ord for OsStr
impl Ord for ErrorKind
impl Ord for IpAddr
impl Ord for Ipv4Addr
impl Ord for Ipv6Addr
impl<'a> Ord for Prefix<'a>
impl<'a> Ord for PrefixComponent<'a>
impl<'a> Ord for Component<'a>
impl<'a> Ord for Components<'a>
impl Ord for PathBuf
impl Ord for Path
impl Ord for Duration
impl Ord for Instant
impl Ord for SystemTime
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/cmp/trait.Ord.html