# Trait core::cmp::PartialOrd [−] [src]

    pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
        fn partial_cmp(&self, other: &Rhs) -> Option<Ordering>;

        fn lt(&self, other: &Rhs) -> bool { ... }
        fn le(&self, other: &Rhs) -> bool { ... }
        fn gt(&self, other: &Rhs) -> bool { ... }
        fn ge(&self, other: &Rhs) -> bool { ... }
    }

Trait for values that can be compared for a sort-order.

The comparison must satisfy, for all `a`, `b` and `c`:

- antisymmetry: if `a < b` then `!(a > b)`, as well as `a > b` implying `!(a < b)`; and
- transitivity: `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.

Note that these requirements mean that the trait itself must be implemented symmetrically and transitively: if `T: PartialOrd<U>` and `U: PartialOrd<V>` then `U: PartialOrd<T>` and `T: PartialOrd<V>`.

PartialOrd only requires implementation of the `partial_cmp` method, with the others generated from default implementations.

However it remains possible to implement the others separately for types which do not have a total order. For example, for floating point numbers, `NaN < 0 == false` and `NaN >= 0 == false` (cf. IEEE 754-2008 section 5.11).

This trait can be used with `#[derive]`.

## Required Methods

### `fn partial_cmp(&self, other: &Rhs) -> Option<Ordering>`

This method returns an ordering between `self` and `other` values if one exists.

# Examples

fn main() { use std::cmp::Ordering; let result = 1.0.partial_cmp(&2.0); assert_eq!(result, Some(Ordering::Less)); let result = 1.0.partial_cmp(&1.0); assert_eq!(result, Some(Ordering::Equal)); let result = 2.0.partial_cmp(&1.0); assert_eq!(result, Some(Ordering::Greater)); }

    use std::cmp::Ordering;

    let result = 1.0.partial_cmp(&2.0);
    assert_eq!(result, Some(Ordering::Less));

    let result = 1.0.partial_cmp(&1.0);
    assert_eq!(result, Some(Ordering::Equal));

    let result = 2.0.partial_cmp(&1.0);
    assert_eq!(result, Some(Ordering::Greater));

When comparison is impossible:

fn main() { let result = std::f64::NAN.partial_cmp(&1.0); assert_eq!(result, None); }

    let result = std::f64::NAN.partial_cmp(&1.0);
    assert_eq!(result, None);

## Provided Methods

### `fn lt(&self, other: &Rhs) -> bool`

This method tests less than (for `self` and `other`) and is used by the `<` operator.

# Examples

fn main() { let result = 1.0 < 2.0; assert_eq!(result, true); let result = 2.0 < 1.0; assert_eq!(result, false); }

    let result = 1.0 < 2.0;
    assert_eq!(result, true);

    let result = 2.0 < 1.0;
    assert_eq!(result, false);

### `fn le(&self, other: &Rhs) -> bool`

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator.

# Examples

fn main() { let result = 1.0 <= 2.0; assert_eq!(result, true); let result = 2.0 <= 2.0; assert_eq!(result, true); }

    let result = 1.0 <= 2.0;
    assert_eq!(result, true);

    let result = 2.0 <= 2.0;
    assert_eq!(result, true);

### `fn gt(&self, other: &Rhs) -> bool`

This method tests greater than (for `self` and `other`) and is used by the `>` operator.

# Examples

fn main() { let result = 1.0 > 2.0; assert_eq!(result, false); let result = 2.0 > 2.0; assert_eq!(result, false); }

    let result = 1.0 > 2.0;
    assert_eq!(result, false);

    let result = 2.0 > 2.0;
    assert_eq!(result, false);

### `fn ge(&self, other: &Rhs) -> bool`

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator.

# Examples

fn main() { let result = 2.0 >= 1.0; assert_eq!(result, true); let result = 2.0 >= 2.0; assert_eq!(result, true); }

    let result = 2.0 >= 1.0;
    assert_eq!(result, true);

    let result = 2.0 >= 2.0;
    assert_eq!(result, true);

## Implementors

- `impl<T: PartialOrd> PartialOrd for Wrapping<T>`
- `impl<T: PartialOrd + Zeroable> PartialOrd for NonZero<T>`
- `impl<Ret> PartialOrd for fn() -> Ret`
- `impl<Ret> PartialOrd for extern "C" fn() -> Ret`
- `impl<Ret> PartialOrd for unsafe fn() -> Ret`
- `impl<Ret> PartialOrd for unsafe extern "C" fn() -> Ret`
- `impl<Ret, A> PartialOrd for fn(A) -> Ret`
- `impl<Ret, A> PartialOrd for extern "C" fn(A) -> Ret`
- `impl<Ret, A> PartialOrd for unsafe fn(A) -> Ret`
- `impl<Ret, A> PartialOrd for unsafe extern "C" fn(A) -> Ret`
- `impl<Ret, A, B> PartialOrd for fn(A, B) -> Ret`
- `impl<Ret, A, B> PartialOrd for extern "C" fn(A, B) -> Ret`
- `impl<Ret, A, B> PartialOrd for unsafe fn(A, B) -> Ret`
- `impl<Ret, A, B> PartialOrd for unsafe extern "C" fn(A, B) -> Ret`
- `impl<Ret, A, B, C> PartialOrd for fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> PartialOrd for extern "C" fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> PartialOrd for unsafe fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C> PartialOrd for unsafe extern "C" fn(A, B, C) -> Ret`
- `impl<Ret, A, B, C, D> PartialOrd for fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> PartialOrd for extern "C" fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> PartialOrd for unsafe fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D> PartialOrd for unsafe extern "C" fn(A, B, C, D) -> Ret`
- `impl<Ret, A, B, C, D, E> PartialOrd for fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> PartialOrd for extern "C" fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> PartialOrd for unsafe fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E> PartialOrd for unsafe extern "C" fn(A, B, C, D, E) -> Ret`
- `impl<Ret, A, B, C, D, E, F> PartialOrd for fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> PartialOrd for extern "C" fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> PartialOrd for unsafe fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F> PartialOrd for unsafe extern "C" fn(A, B, C, D, E, F) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> PartialOrd for fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> PartialOrd for extern "C" fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> PartialOrd for unsafe fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G> PartialOrd for unsafe extern "C" fn(A, B, C, D, E, F, G) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> PartialOrd for fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> PartialOrd for extern "C" fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> PartialOrd for unsafe fn(A, B, C, D, E, F, G, H) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H> PartialOrd 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> PartialOrd for fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> PartialOrd for extern "C" fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> PartialOrd for unsafe fn(A, B, C, D, E, F, G, H, I) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I> PartialOrd 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> PartialOrd for fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> PartialOrd for extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> PartialOrd for unsafe fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J> PartialOrd for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret`
- `impl<Ret, A, B, C, D, E, F, G, H, I, J, K> PartialOrd for 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> PartialOrd 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, J, K> PartialOrd for unsafe 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> PartialOrd 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, L> PartialOrd for 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> PartialOrd 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, K, L> PartialOrd for unsafe 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> PartialOrd for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret`
- `impl<T: ?Sized> PartialOrd for *const T`
- `impl<T: ?Sized> PartialOrd for *mut T`
- `impl<T: ?Sized> PartialOrd for PhantomData<T>`
- `impl PartialOrd for ()`
- `impl PartialOrd for bool`
- `impl PartialOrd for f32`
- `impl PartialOrd for f64`
- `impl PartialOrd for char`
- `impl PartialOrd for usize`
- `impl PartialOrd for u8`
- `impl PartialOrd for u16`
- `impl PartialOrd for u32`
- `impl PartialOrd for u64`
- `impl PartialOrd for isize`
- `impl PartialOrd for i8`
- `impl PartialOrd for i16`
- `impl PartialOrd for i32`
- `impl PartialOrd for i64`
- `impl<'a, 'b, A: ?Sized, B: ?Sized> PartialOrd<&'b B> for &'a A where A: PartialOrd<B>`
- `impl<'a, 'b, A: ?Sized, B: ?Sized> PartialOrd<&'b mut B> for &'a mut A where A: PartialOrd<B>`
- `impl PartialOrd for Ordering`
- `impl<T: PartialOrd> PartialOrd for [T; 0]`
- `impl<T: PartialOrd> PartialOrd for [T; 1]`
- `impl<T: PartialOrd> PartialOrd for [T; 2]`
- `impl<T: PartialOrd> PartialOrd for [T; 3]`
- `impl<T: PartialOrd> PartialOrd for [T; 4]`
- `impl<T: PartialOrd> PartialOrd for [T; 5]`
- `impl<T: PartialOrd> PartialOrd for [T; 6]`
- `impl<T: PartialOrd> PartialOrd for [T; 7]`
- `impl<T: PartialOrd> PartialOrd for [T; 8]`
- `impl<T: PartialOrd> PartialOrd for [T; 9]`
- `impl<T: PartialOrd> PartialOrd for [T; 10]`
- `impl<T: PartialOrd> PartialOrd for [T; 11]`
- `impl<T: PartialOrd> PartialOrd for [T; 12]`
- `impl<T: PartialOrd> PartialOrd for [T; 13]`
- `impl<T: PartialOrd> PartialOrd for [T; 14]`
- `impl<T: PartialOrd> PartialOrd for [T; 15]`
- `impl<T: PartialOrd> PartialOrd for [T; 16]`
- `impl<T: PartialOrd> PartialOrd for [T; 17]`
- `impl<T: PartialOrd> PartialOrd for [T; 18]`
- `impl<T: PartialOrd> PartialOrd for [T; 19]`
- `impl<T: PartialOrd> PartialOrd for [T; 20]`
- `impl<T: PartialOrd> PartialOrd for [T; 21]`
- `impl<T: PartialOrd> PartialOrd for [T; 22]`
- `impl<T: PartialOrd> PartialOrd for [T; 23]`
- `impl<T: PartialOrd> PartialOrd for [T; 24]`
- `impl<T: PartialOrd> PartialOrd for [T; 25]`
- `impl<T: PartialOrd> PartialOrd for [T; 26]`
- `impl<T: PartialOrd> PartialOrd for [T; 27]`
- `impl<T: PartialOrd> PartialOrd for [T; 28]`
- `impl<T: PartialOrd> PartialOrd for [T; 29]`
- `impl<T: PartialOrd> PartialOrd for [T; 30]`
- `impl<T: PartialOrd> PartialOrd for [T; 31]`
- `impl<T: PartialOrd> PartialOrd for [T; 32]`
- `impl<T: PartialOrd> PartialOrd for Option<T>`
- `impl<T: PartialOrd, E: PartialOrd> PartialOrd for Result<T, E>`
- `impl<T: PartialOrd> PartialOrd for [T]`
- `impl PartialOrd for str`
- `impl<A: PartialOrd + PartialEq> PartialOrd for (A,)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq> PartialOrd for (A, B)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq> PartialOrd for (A, B, C)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq> PartialOrd for (A, B, C, D)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq, G: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F, G)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq, G: PartialOrd + PartialEq, H: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F, G, H)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq, G: PartialOrd + PartialEq, H: PartialOrd + PartialEq, I: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F, G, H, I)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq, G: PartialOrd + PartialEq, H: PartialOrd + PartialEq, I: PartialOrd + PartialEq, J: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F, G, H, I, J)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq, G: PartialOrd + PartialEq, H: PartialOrd + PartialEq, I: PartialOrd + PartialEq, J: PartialOrd + PartialEq, K: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F, G, H, I, J, K)`
- `impl<A: PartialOrd + PartialEq, B: PartialOrd + PartialEq, C: PartialOrd + PartialEq, D: PartialOrd + PartialEq, E: PartialOrd + PartialEq, F: PartialOrd + PartialEq, G: PartialOrd + PartialEq, H: PartialOrd + PartialEq, I: PartialOrd + PartialEq, J: PartialOrd + PartialEq, K: PartialOrd + PartialEq, L: PartialOrd + PartialEq> PartialOrd for (A, B, C, D, E, F, G, H, I, J, K, L)`

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