1.0.0[−][src]Enum core::cmp::Ordering

```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]

`pub fn reverse(self) -> Ordering`[src]

Reverses 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```

`pub fn then(self, other: Ordering) -> Ordering`1.17.0[src]

Chains two orderings.

Returns `self` when it's not `Equal`. Otherwise returns `other`.

Examples

```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```

`pub fn then_with<F: FnOnce() -> Ordering>(self, f: F) -> Ordering`1.17.0[src]

Chains the ordering with the given function.

Returns `self` when it's not `Equal`. Otherwise calls `f` and returns the result.

Examples

```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 PartialEq<Ordering> for Ordering`[src]

```#[must_use] fn ne(&self, other: &Rhs) -> bool```[src]

This method tests for `!=`.

`impl Ord for Ordering`[src]

`fn max(self, other: Self) -> Self where    Self: Sized, `1.21.0[src]

Compares and returns the maximum of two values. Read more

`fn min(self, other: Self) -> Self where    Self: Sized, `1.21.0[src]

Compares and returns the minimum of two values. Read more

`fn clamp(self, min: Self, max: Self) -> Self where    Self: Sized, `[src]

🔬 This is a nightly-only experimental API. (`clamp` #44095)

Restrict a value to a certain interval. Read more

`impl PartialOrd<Ordering> for Ordering`[src]

```#[must_use] fn lt(&self, other: &Rhs) -> bool```[src]

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

```#[must_use] fn le(&self, other: &Rhs) -> bool```[src]

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

```#[must_use] fn gt(&self, other: &Rhs) -> bool```[src]

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

```#[must_use] fn ge(&self, other: &Rhs) -> bool```[src]

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

`impl Clone for Ordering`[src]

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

Performs copy-assignment from `source`. Read more

`impl Hash for Ordering`[src]

`fn hash_slice<H: Hasher>(data: &[Self], state: &mut H) where    Self: Sized, `1.3.0[src]

Feeds a slice of this type into the given [`Hasher`]. Read more

Blanket Implementations

`impl<T, U> TryInto<U> for T where    U: TryFrom<T>, `[src]

`type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

`impl<T, U> TryFrom<U> for T where    U: Into<T>, `[src]

`type Error = Infallible`

The type returned in the event of a conversion error.