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Struct Reverse

#[repr(transparent)]pub struct Reverse<T>(pub T);

A helper struct for reverse ordering.

This struct is a helper to be used with functions like Vec::sort_by_key and can be used to reverse order a part of a key.

Examples

use std::cmp::Reverse;

let mut v = vec![1, 2, 3, 4, 5, 6];
v.sort_by_key(|&num| (num > 3, Reverse(num)));
assert_eq!(v, vec![3, 2, 1, 6, 5, 4]);

Tuple Fields

0: T

Trait Implementations

1.19.0Source

impl<T> Clone for Reverse<T>where
    T: Clone,

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fn clone(&self) -> Reverse<T>

Returns a duplicate of the value. Read more

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fn clone_from(&mut self, source: &Reverse<T>)

Performs copy-assignment from source. Read more

1.19.0Source

impl<T> Debug for Reverse<T>where
    T: Debug,

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more

1.19.0 (const: unstable)Source

impl<T> Default for Reverse<T>where
    T: Default,

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fn default() -> Reverse<T>

Returns the “default value” for a type. Read more

1.19.0Source

impl<T> Hash for Reverse<T>where
    T: Hash,

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

Feeds this value into the given Hasher. Read more

1.3.0Source

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

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

1.19.0 (const: unstable)Source

impl<T> Ord for Reverse<T>where
    T: Ord,

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fn cmp(&self, other: &Reverse<T>) -> Ordering

This method returns an Ordering between self and other. Read more

1.21.0Source

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values. Read more

1.21.0Source

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values. Read more

1.50.0Source

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized,

Restrict a value to a certain interval. Read more

1.19.0 (const: unstable)Source

impl<T> PartialEq for Reverse<T>where
    T: PartialEq,

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fn eq(&self, other: &Reverse<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

1.0.0Source

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

1.19.0 (const: unstable)Source

impl<T> PartialOrd for Reverse<T>where
    T: PartialOrd,

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

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

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fn lt(&self, other: &Reverse<T>) -> bool

Tests less than (for self and other) and is used by the < operator. Read more

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fn le(&self, other: &Reverse<T>) -> bool

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

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fn gt(&self, other: &Reverse<T>) -> bool

Tests greater than (for self and other) and is used by the > operator. Read more

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fn ge(&self, other: &Reverse<T>) -> bool

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

1.19.0Source

impl<T> Copy for Reverse<T>where
    T: Copy,

1.19.0 (const: unstable)Source

impl<T> Eq for Reverse<T>where
    T: Eq,

1.19.0Source

impl<T> StructuralPartialEq for Reverse<T>

Auto Trait Implementations

impl<T> Freeze for Reverse<T>where
    T: Freeze,

impl<T> RefUnwindSafe for Reverse<T>where
    T: RefUnwindSafe,

impl<T> Send for Reverse<T>where
    T: Send,

impl<T> Sync for Reverse<T>where
    T: Sync,

impl<T> Unpin for Reverse<T>where
    T: Unpin,

impl<T> UnwindSafe for Reverse<T>where
    T: UnwindSafe,

Blanket Implementations

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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impl<T> Borrow<T> for Twhere
    T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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impl<T> CloneToUninit for Twhere
    T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit #126799)

Performs copy-assignment from self to dest. Read more

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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere
    T: Clone,

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type Owned = T

The resulting type after obtaining ownership.

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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.

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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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

The type returned in the event of a conversion error.

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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

© 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/struct.Reverse.html