#[repr(transparent)]pub struct Reverse<T>(pub T);
Expand description
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§
source§impl<T> Ord for Reverse<T>where
T: Ord,
impl<T> Ord for Reverse<T>where T: Ord,
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
Compares and returns the maximum of two values. Read more
source§impl<T> PartialEq for Reverse<T>where
T: PartialEq,
impl<T> PartialEq for Reverse<T>where T: PartialEq,
source§impl<T> PartialOrd for Reverse<T>where
T: PartialOrd,
impl<T> PartialOrd for Reverse<T>where T: PartialOrd,
source§fn le(&self, other: &Reverse<T>) -> bool
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 moreimpl<T> Copy for Reverse<T>where T: Copy,
impl<T> Eq for Reverse<T>where T: Eq,
impl<T> StructuralEq for Reverse<T>
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§
source§impl<T> Also for T
impl<T> Also for T
source§impl<T> AnyExt for Twhere
T: Any,
impl<T> AnyExt for Twhere T: Any,
source§fn type_name(&self) -> &'static str
fn type_name(&self) -> &'static str
Available on crate feature
any
only.Returns the type name of
self
. Read moresource§fn as_any_ref(&self) -> &dyn Anywhere
Self: Sized,
fn as_any_ref(&self) -> &dyn Anywhere Self: Sized,
Available on crate feature
any
only.source§fn as_any_mut(&mut self) -> &mut dyn Anywhere
Self: Sized,
fn as_any_mut(&mut self) -> &mut dyn Anywhere Self: Sized,
Available on crate feature
any
only.source§impl<T, Res> Apply<Res> for Twhere
T: ?Sized,
impl<T, Res> Apply<Res> for Twhere T: ?Sized,
source§fn apply<F: FnOnce(Self) -> Res>(self, f: F) -> Reswhere
Self: Sized,
fn apply<F: FnOnce(Self) -> Res>(self, f: F) -> Reswhere Self: Sized,
Available on crate feature
result
only.Apply a function which takes the parameter by value.
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
source§impl<T> CheckedAs for T
impl<T> CheckedAs for T
source§fn checked_as<Dst>(self) -> Option<Dst>where
T: CheckedCast<Dst>,
fn checked_as<Dst>(self) -> Option<Dst>where T: CheckedCast<Dst>,
Casts the value.
source§impl<Src, Dst> CheckedCastFrom<Src> for Dstwhere
Src: CheckedCast<Dst>,
impl<Src, Dst> CheckedCastFrom<Src> for Dstwhere Src: CheckedCast<Dst>,
source§fn checked_cast_from(src: Src) -> Option<Dst>
fn checked_cast_from(src: Src) -> Option<Dst>
Casts the value.
§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Checks if this value is equivalent to the given key. Read more
source§impl<T> Mem for Twhere
T: ?Sized,
impl<T> Mem for Twhere T: ?Sized,
source§const NEEDS_DROP: bool = _
const NEEDS_DROP: bool = _
Available on crate feature
mem
only.Whether dropping values of this type matters.
source§fn mem_needs_drop(&self) -> bool
fn mem_needs_drop(&self) -> bool
Available on crate feature
mem
only.Returns
true
if dropping values of this type matters.source§fn mem_drop(self)where
Self: Sized,
fn mem_drop(self)where Self: Sized,
Available on crate feature
mem
only.Drops
self
by running its destructor.source§fn mem_forget(self)where
Self: Sized,
fn mem_forget(self)where Self: Sized,
Available on crate feature
mem
only.Forgets about
self
without running its destructor.source§fn mem_replace(&mut self, other: Self) -> Selfwhere
Self: Sized,
fn mem_replace(&mut self, other: Self) -> Selfwhere Self: Sized,
Available on crate feature
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only.Replaces
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with other, returning the previous value of self
.source§fn mem_take(&mut self) -> Selfwhere
Self: Default,
fn mem_take(&mut self) -> Selfwhere Self: Default,
Available on crate feature
mem
only.Replaces
self
with its default value, returning the previous value of self
.source§fn mem_swap(&mut self, other: &mut Self)where
Self: Sized,
fn mem_swap(&mut self, other: &mut Self)where Self: Sized,
Available on crate feature
mem
only.Swaps the value of
self
and other
without deinitializing either one.source§impl<T> OverflowingAs for T
impl<T> OverflowingAs for T
source§fn overflowing_as<Dst>(self) -> (Dst, bool)where
T: OverflowingCast<Dst>,
fn overflowing_as<Dst>(self) -> (Dst, bool)where T: OverflowingCast<Dst>,
Casts the value.
source§impl<Src, Dst> OverflowingCastFrom<Src> for Dstwhere
Src: OverflowingCast<Dst>,
impl<Src, Dst> OverflowingCastFrom<Src> for Dstwhere Src: OverflowingCast<Dst>,
source§fn overflowing_cast_from(src: Src) -> (Dst, bool)
fn overflowing_cast_from(src: Src) -> (Dst, bool)
Casts the value.
source§impl<T> SaturatingAs for T
impl<T> SaturatingAs for T
source§fn saturating_as<Dst>(self) -> Dstwhere
T: SaturatingCast<Dst>,
fn saturating_as<Dst>(self) -> Dstwhere T: SaturatingCast<Dst>,
Casts the value.
source§impl<Src, Dst> SaturatingCastFrom<Src> for Dstwhere
Src: SaturatingCast<Dst>,
impl<Src, Dst> SaturatingCastFrom<Src> for Dstwhere Src: SaturatingCast<Dst>,
source§fn saturating_cast_from(src: Src) -> Dst
fn saturating_cast_from(src: Src) -> Dst
Casts the value.
source§impl<T> Size for T
impl<T> Size for T
source§const BYTE_ALIGN: usize = _
const BYTE_ALIGN: usize = _
Available on crate feature
mem
only.The alignment of this type in bytes.
source§const BYTE_SIZE: usize = _
const BYTE_SIZE: usize = _
Available on crate feature
mem
only.The size of this type in bytes.
source§const PTR_SIZE: usize = 4usize
const PTR_SIZE: usize = 4usize
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mem
only.The size of a pointer in bytes, for the current platform.
source§fn byte_align(&self) -> usize
fn byte_align(&self) -> usize
Available on crate feature
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only.Returns the alignment of this type in bytes.
source§impl<T> UnwrappedAs for T
impl<T> UnwrappedAs for T
source§fn unwrapped_as<Dst>(self) -> Dstwhere
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fn unwrapped_as<Dst>(self) -> Dstwhere T: UnwrappedCast<Dst>,
Casts the value.
source§impl<Src, Dst> UnwrappedCastFrom<Src> for Dstwhere
Src: UnwrappedCast<Dst>,
impl<Src, Dst> UnwrappedCastFrom<Src> for Dstwhere Src: UnwrappedCast<Dst>,
source§fn unwrapped_cast_from(src: Src) -> Dst
fn unwrapped_cast_from(src: Src) -> Dst
Casts the value.
source§impl<T> WrappingAs for T
impl<T> WrappingAs for T
source§fn wrapping_as<Dst>(self) -> Dstwhere
T: WrappingCast<Dst>,
fn wrapping_as<Dst>(self) -> Dstwhere T: WrappingCast<Dst>,
Casts the value.
source§impl<Src, Dst> WrappingCastFrom<Src> for Dstwhere
Src: WrappingCast<Dst>,
impl<Src, Dst> WrappingCastFrom<Src> for Dstwhere Src: WrappingCast<Dst>,
source§fn wrapping_cast_from(src: Src) -> Dst
fn wrapping_cast_from(src: Src) -> Dst
Casts the value.