pub enum Entry<'a, K, V, A = Global> where
K: 'a,
V: 'a,
A: Allocator + Clone, {
Vacant(VacantEntry<'a, K, V, A>),
Occupied(OccupiedEntry<'a, K, V, A>),
}
Expand description
Variants
Vacant(VacantEntry<'a, K, V, A>)
A vacant entry.
Occupied(OccupiedEntry<'a, K, V, A>)
An occupied entry.
Implementations
sourceimpl<'a, K, V, A> Entry<'a, K, V, A> where
K: Ord,
A: Allocator + Clone,
impl<'a, K, V, A> Entry<'a, K, V, A> where
K: Ord,
A: Allocator + Clone,
sourcepub fn or_insert(self, default: V) -> &'a mut V
pub fn or_insert(self, default: V) -> &'a mut V
Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.
Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, usize> = BTreeMap::new();
map.entry("poneyland").or_insert(12);
assert_eq!(map["poneyland"], 12);
sourcepub fn or_insert_with<F>(self, default: F) -> &'a mut V where
F: FnOnce() -> V,
pub fn or_insert_with<F>(self, default: F) -> &'a mut V where
F: FnOnce() -> V,
Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.
Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, String> = BTreeMap::new();
let s = "hoho".to_string();
map.entry("poneyland").or_insert_with(|| s);
assert_eq!(map["poneyland"], "hoho".to_string());
1.50.0 · sourcepub fn or_insert_with_key<F>(self, default: F) -> &'a mut V where
F: for<'_> FnOnce(&K) -> V,
pub fn or_insert_with_key<F>(self, default: F) -> &'a mut V where
F: for<'_> FnOnce(&K) -> V,
Ensures a value is in the entry by inserting, if empty, the result of the default function.
This method allows for generating key-derived values for insertion by providing the default
function a reference to the key that was moved during the .entry(key)
method call.
The reference to the moved key is provided so that cloning or copying the key is
unnecessary, unlike with .or_insert_with(|| ... )
.
Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, usize> = BTreeMap::new();
map.entry("poneyland").or_insert_with_key(|key| key.chars().count());
assert_eq!(map["poneyland"], 9);
1.10.0 · sourcepub fn key(&self) -> &K
pub fn key(&self) -> &K
Returns a reference to this entry’s key.
Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, usize> = BTreeMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");
1.26.0 · sourcepub fn and_modify<F>(self, f: F) -> Entry<'a, K, V, A> where
F: for<'_> FnOnce(&mut V),
pub fn and_modify<F>(self, f: F) -> Entry<'a, K, V, A> where
F: for<'_> FnOnce(&mut V),
Provides in-place mutable access to an occupied entry before any potential inserts into the map.
Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, usize> = BTreeMap::new();
map.entry("poneyland")
.and_modify(|e| { *e += 1 })
.or_insert(42);
assert_eq!(map["poneyland"], 42);
map.entry("poneyland")
.and_modify(|e| { *e += 1 })
.or_insert(42);
assert_eq!(map["poneyland"], 43);
sourceimpl<'a, K, V, A> Entry<'a, K, V, A> where
K: Ord,
V: Default,
A: Allocator + Clone,
impl<'a, K, V, A> Entry<'a, K, V, A> where
K: Ord,
V: Default,
A: Allocator + Clone,
1.28.0 · sourcepub fn or_default(self) -> &'a mut V
pub fn or_default(self) -> &'a mut V
Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.
Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, Option<usize>> = BTreeMap::new();
map.entry("poneyland").or_default();
assert_eq!(map["poneyland"], None);
Trait Implementations
Auto Trait Implementations
impl<'a, K, V, A> RefUnwindSafe for Entry<'a, K, V, A> where
A: RefUnwindSafe,
K: RefUnwindSafe,
V: RefUnwindSafe,
impl<'a, K, V, A> Send for Entry<'a, K, V, A> where
A: Send,
K: Send,
V: Send,
impl<'a, K, V, A> Sync for Entry<'a, K, V, A> where
A: Sync,
K: Sync,
V: Sync,
impl<'a, K, V, A> Unpin for Entry<'a, K, V, A> where
A: Unpin,
K: Unpin,
impl<'a, K, V, A = Global> !UnwindSafe for Entry<'a, K, V, A>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> Downcast for T where
T: Any,
impl<T> Downcast for T where
T: Any,
sourcefn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>ⓘNotable traits for Box<W, Global>impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;
fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>ⓘNotable traits for Box<W, Global>impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;
W: Write + ?Sized, impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;
Convert Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
. Box<dyn Any>
can
then be further downcast
into Box<ConcreteType>
where ConcreteType
implements Trait
. Read more
sourcefn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
Convert Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
. Read more
sourcefn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
Convert &Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s. Read more
sourcefn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
Convert &mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s. Read more
sourceimpl<T> DowncastSync for T where
T: Any + Send + Sync,
impl<T> DowncastSync for T where
T: Any + Send + Sync,
sourceimpl<A> DynCastExt for A
impl<A> DynCastExt for A
sourcefn dyn_cast<T>(
self
) -> Result<<A as DynCastExtHelper<T>>::Target, <A as DynCastExtHelper<T>>::Source> where
A: DynCastExtHelper<T>,
T: ?Sized,
fn dyn_cast<T>(
self
) -> Result<<A as DynCastExtHelper<T>>::Target, <A as DynCastExtHelper<T>>::Source> where
A: DynCastExtHelper<T>,
T: ?Sized,
Use this to cast from one trait object type to another. Read more
sourcefn dyn_upcast<T>(self) -> <A as DynCastExtAdvHelper<T, T>>::Target where
A: DynCastExtAdvHelper<T, T, Source = <A as DynCastExtAdvHelper<T, T>>::Target>,
T: ?Sized,
fn dyn_upcast<T>(self) -> <A as DynCastExtAdvHelper<T, T>>::Target where
A: DynCastExtAdvHelper<T, T, Source = <A as DynCastExtAdvHelper<T, T>>::Target>,
T: ?Sized,
Use this to upcast a trait to one of its supertraits. Read more
sourcefn dyn_cast_adv<F, T>(
self
) -> Result<<A as DynCastExtAdvHelper<F, T>>::Target, <A as DynCastExtAdvHelper<F, T>>::Source> where
A: DynCastExtAdvHelper<F, T>,
F: ?Sized,
T: ?Sized,
fn dyn_cast_adv<F, T>(
self
) -> Result<<A as DynCastExtAdvHelper<F, T>>::Target, <A as DynCastExtAdvHelper<F, T>>::Source> where
A: DynCastExtAdvHelper<F, T>,
F: ?Sized,
T: ?Sized,
sourcefn dyn_cast_with_config<C>(
self
) -> Result<<A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Target, <A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Source> where
C: DynCastConfig,
A: DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>,
fn dyn_cast_with_config<C>(
self
) -> Result<<A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Target, <A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Source> where
C: DynCastConfig,
A: DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>,
Use this to cast from one trait object type to another. With this method the type parameter is a config type that uniquely specifies which cast should be preformed. Read more