pub enum Entry<'a, K, V>where
K: 'a,
V: 'a,{
Occupied(OccupiedEntry<'a, K, V>),
Vacant(VacantEntry<'a, K, V>),
}
Expand description
Variants§
Occupied(OccupiedEntry<'a, K, V>)
An occupied entry.
Vacant(VacantEntry<'a, K, V>)
A vacant entry.
Implementations§
source§impl<'a, K, V> Entry<'a, K, V>
impl<'a, K, V> Entry<'a, K, V>
1.0.0 · 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::HashMap;
let mut map: HashMap<&str, u32> = HashMap::new();
map.entry("poneyland").or_insert(3);
assert_eq!(map["poneyland"], 3);
*map.entry("poneyland").or_insert(10) *= 2;
assert_eq!(map["poneyland"], 6);
1.0.0 · sourcepub fn or_insert_with<F>(self, default: F) -> &'a mut Vwhere
F: FnOnce() -> V,
pub fn or_insert_with<F>(self, default: F) -> &'a mut Vwhere
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::HashMap;
let mut map = HashMap::new();
let value = "hoho";
map.entry("poneyland").or_insert_with(|| value);
assert_eq!(map["poneyland"], "hoho");
1.50.0 · sourcepub fn or_insert_with_key<F>(self, default: F) -> &'a mut V
pub fn or_insert_with_key<F>(self, default: F) -> &'a mut 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::HashMap;
let mut map: HashMap<&str, usize> = HashMap::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::HashMap;
let mut map: HashMap<&str, u32> = HashMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");
1.26.0 · sourcepub fn and_modify<F>(self, f: F) -> Entry<'a, K, V>
pub fn and_modify<F>(self, f: F) -> Entry<'a, K, V>
Provides in-place mutable access to an occupied entry before any potential inserts into the map.
§Examples
use std::collections::HashMap;
let mut map: HashMap<&str, u32> = HashMap::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);
sourcepub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V>
🔬This is a nightly-only experimental API. (entry_insert
)
pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V>
entry_insert
)Sets the value of the entry, and returns an OccupiedEntry
.
§Examples
#![feature(entry_insert)]
use std::collections::HashMap;
let mut map: HashMap<&str, String> = HashMap::new();
let entry = map.entry("poneyland").insert_entry("hoho".to_string());
assert_eq!(entry.key(), &"poneyland");
source§impl<'a, K, V> Entry<'a, K, V>where
V: Default,
impl<'a, K, V> Entry<'a, K, V>where
V: Default,
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::HashMap;
let mut map: HashMap<&str, Option<u32>> = HashMap::new();
map.entry("poneyland").or_default();
assert_eq!(map["poneyland"], None);
Trait Implementations§
Auto Trait Implementations§
impl<'a, K, V> Freeze for Entry<'a, K, V>where
K: Freeze,
impl<'a, K, V> RefUnwindSafe for Entry<'a, K, V>where
K: RefUnwindSafe,
V: RefUnwindSafe,
impl<'a, K, V> Send for Entry<'a, K, V>
impl<'a, K, V> Sync for Entry<'a, K, V>
impl<'a, K, V> Unpin for Entry<'a, K, V>where
K: Unpin,
impl<'a, K, V> !UnwindSafe for Entry<'a, K, V>
Blanket Implementations§
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
source§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
T: Any,
source§fn into_any(self: Box<T>) -> Box<dyn Any>
fn into_any(self: Box<T>) -> Box<dyn Any>
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
.source§fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
.source§fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
&Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s.source§fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
&mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s.source§impl<T> DowncastSync for T
impl<T> DowncastSync for T
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
source§fn to_subset(&self) -> Option<SS>
fn to_subset(&self) -> Option<SS>
self
from the equivalent element of its
superset. Read moresource§fn is_in_subset(&self) -> bool
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self
is actually part of its subset T
(and can be converted to it).source§fn to_subset_unchecked(&self) -> SS
fn to_subset_unchecked(&self) -> SS
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but without any property checks. Always succeeds.source§fn from_subset(element: &SS) -> SP
fn from_subset(element: &SS) -> SP
self
to the equivalent element of its superset.