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Struct std::cmp::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

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impl<T> Clone for Reverse<T>
where
    T: Clone,
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fn clone(&self) -> Reverse<T>
Returns a copy of the value. Read more
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fn clone_from(&mut self, other: &Reverse<T>)
Performs copy-assignment from source. Read more
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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
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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
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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
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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) -> Self
where
    Self: Sized,
Compares and returns the maximum of two values. Read more
1.21.0source 
fn min(self, other: Self) -> Self
where
    Self: Sized,
Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where
    Self: Sized + PartialOrd,
Restrict a value to a certain interval. Read more
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impl<T> PartialEq for Reverse<T>
where
    T: PartialEq,
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fn eq(&self, other: &Reverse<T>) -> bool
This method tests for self and other values to be equal, and is used by ==.
1.0.0source 
fn ne(&self, other: &Rhs) -> bool
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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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
This method 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
This method 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
This method 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
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<T> Copy for Reverse<T>
where
    T: Copy,
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impl<T> Eq for Reverse<T>
where
    T: Eq,
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impl<T> StructuralEq for Reverse<T>
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impl<T> StructuralPartialEq for Reverse<T>

Auto Trait Implementations

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 T
where
    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 T
where
    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 T
where
    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> 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 T
where
    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 T
where
    T: Clone,
 
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 T
where
    U: Into<T>,
 
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 T
where
    U: TryFrom<T>,
 
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