1.0.0[−][src]Enum alloc::collections::btree_map::Entry
A view into a single entry in a map, which may either be vacant or occupied.
Variants
Vacant(VacantEntry<'a, K, V>)
A vacant entry.
Occupied(OccupiedEntry<'a, K, V>)
An occupied entry.
Methods
impl<'a, K: Ord, V> Entry<'a, K, V>
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pub fn or_insert(self, default: V) -> &'a mut V
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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);
pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V
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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());
pub fn key(&self) -> &K
1.10.0[src]
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");
pub fn and_modify<F>(self, f: F) -> Self where
F: FnOnce(&mut V),
1.26.0[src]
F: 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);
impl<'a, K: Ord, V: Default> Entry<'a, K, V>
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pub fn or_default(self) -> &'a mut V
1.28.0[src]
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> Send for Entry<'a, K, V> where
K: Send,
V: Send,
K: Send,
V: Send,
impl<'a, K, V> Sync for Entry<'a, K, V> where
K: Sync,
V: Sync,
K: Sync,
V: Sync,
Blanket Implementations
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,