# Enum std::cmp::Ordering 1.0.0
[−]
[src]

pub enum Ordering { Less, Equal, Greater, }

An `Ordering`

is the result of a comparison between two values.

# Examples

use std::cmp::Ordering; let result = 1.cmp(&2); assert_eq!(Ordering::Less, result); let result = 1.cmp(&1); assert_eq!(Ordering::Equal, result); let result = 2.cmp(&1); assert_eq!(Ordering::Greater, result);Run

## Variants

`Less`

An ordering where a compared value is less [than another].

`Equal`

An ordering where a compared value is equal [to another].

`Greater`

An ordering where a compared value is greater [than another].

## Methods

`impl Ordering`

[src]

`fn reverse(self) -> Ordering`

Reverse the `Ordering`

.

`Less`

becomes`Greater`

.`Greater`

becomes`Less`

.`Equal`

becomes`Equal`

.

# Examples

Basic behavior:

use std::cmp::Ordering; assert_eq!(Ordering::Less.reverse(), Ordering::Greater); assert_eq!(Ordering::Equal.reverse(), Ordering::Equal); assert_eq!(Ordering::Greater.reverse(), Ordering::Less);Run

This method can be used to reverse a comparison:

let mut data: &mut [_] = &mut [2, 10, 5, 8]; // sort the array from largest to smallest. data.sort_by(|a, b| a.cmp(b).reverse()); let b: &mut [_] = &mut [10, 8, 5, 2]; assert!(data == b);Run

`fn then(self, other: Ordering) -> Ordering`

*Unstable (*

`ordering_chaining`

#37053)Chains two orderings.

Returns `self`

when it's not `Equal`

. Otherwise returns `other`

.

# Examples

#![feature(ordering_chaining)] use std::cmp::Ordering; let result = Ordering::Equal.then(Ordering::Less); assert_eq!(result, Ordering::Less); let result = Ordering::Less.then(Ordering::Equal); assert_eq!(result, Ordering::Less); let result = Ordering::Less.then(Ordering::Greater); assert_eq!(result, Ordering::Less); let result = Ordering::Equal.then(Ordering::Equal); assert_eq!(result, Ordering::Equal); let x: (i64, i64, i64) = (1, 2, 7); let y: (i64, i64, i64) = (1, 5, 3); let result = x.0.cmp(&y.0).then(x.1.cmp(&y.1)).then(x.2.cmp(&y.2)); assert_eq!(result, Ordering::Less);Run

`fn then_with<F>(self, f: F) -> Ordering where F: FnOnce() -> Ordering`

*Unstable (*

`ordering_chaining`

#37053)Chains the ordering with the given function.

Returns `self`

when it's not `Equal`

. Otherwise calls `f`

and returns
the result.

# Examples

#![feature(ordering_chaining)] use std::cmp::Ordering; let result = Ordering::Equal.then_with(|| Ordering::Less); assert_eq!(result, Ordering::Less); let result = Ordering::Less.then_with(|| Ordering::Equal); assert_eq!(result, Ordering::Less); let result = Ordering::Less.then_with(|| Ordering::Greater); assert_eq!(result, Ordering::Less); let result = Ordering::Equal.then_with(|| Ordering::Equal); assert_eq!(result, Ordering::Equal); let x: (i64, i64, i64) = (1, 2, 7); let y: (i64, i64, i64) = (1, 5, 3); let result = x.0.cmp(&y.0).then_with(|| x.1.cmp(&y.1)).then_with(|| x.2.cmp(&y.2)); assert_eq!(result, Ordering::Less);Run

## Trait Implementations

`impl Copy for Ordering`

[src]

`impl Debug for Ordering`

[src]

`fn fmt(&self, __arg_0: &mut Formatter) -> Result<(), Error>`

Formats the value using the given formatter.

`impl Ord for Ordering`

[src]

`fn cmp(&self, other: &Ordering) -> Ordering`

This method returns an `Ordering`

between `self`

and `other`

. Read more

`impl PartialOrd<Ordering> for Ordering`

[src]

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

This method returns an ordering between `self`

and `other`

values if one exists. Read more

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

This method tests less than (for `self`

and `other`

) and is used by the `<`

operator. Read more

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

This method tests less than or equal to (for `self`

and `other`

) and is used by the `<=`

operator. Read more

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

This method tests greater than (for `self`

and `other`

) and is used by the `>`

operator. Read more

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

This method tests greater than or equal to (for `self`

and `other`

) and is used by the `>=`

operator. Read more

`impl PartialEq<Ordering> for Ordering`

[src]

`fn eq(&self, __arg_0: &Ordering) -> bool`

This method tests for `self`

and `other`

values to be equal, and is used by `==`

. Read more

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

This method tests for `!=`

.

`impl Clone for Ordering`

[src]

`fn clone(&self) -> Ordering`

Returns a copy of the value. Read more

`fn clone_from(&mut self, source: &Self)`

Performs copy-assignment from `source`

. Read more

`impl Hash for Ordering`

[src]

`fn hash<__H>(&self, __arg_0: &mut __H) where __H: Hasher`

Feeds this value into the state given, updating the hasher as necessary.

`fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher`

1.3.0

Feeds a slice of this type into the state provided.