1.0.0[−][src]Struct std::collections::hash_map::OccupiedEntry
A view into an occupied entry in a HashMap
.
It is part of the Entry
enum.
Methods
impl<'a, K, V> OccupiedEntry<'a, K, V>
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ⓘImportant traits for &'_ mut Fpub fn key(&self) -> &K
1.10.0[src]
Gets a reference to the key in the entry.
Examples
use std::collections::HashMap; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); assert_eq!(map.entry("poneyland").key(), &"poneyland");Run
pub fn remove_entry(self) -> (K, V)
1.12.0[src]
Take the ownership of the key and value from the map.
Examples
use std::collections::HashMap; use std::collections::hash_map::Entry; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); if let Entry::Occupied(o) = map.entry("poneyland") { // We delete the entry from the map. o.remove_entry(); } assert_eq!(map.contains_key("poneyland"), false);Run
ⓘImportant traits for &'_ mut Fpub fn get(&self) -> &V
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Gets a reference to the value in the entry.
Examples
use std::collections::HashMap; use std::collections::hash_map::Entry; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); if let Entry::Occupied(o) = map.entry("poneyland") { assert_eq!(o.get(), &12); }Run
ⓘImportant traits for &'_ mut Fpub fn get_mut(&mut self) -> &mut V
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Gets a mutable reference to the value in the entry.
If you need a reference to the OccupiedEntry
which may outlive the
destruction of the Entry
value, see into_mut
.
Examples
use std::collections::HashMap; use std::collections::hash_map::Entry; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); assert_eq!(map["poneyland"], 12); if let Entry::Occupied(mut o) = map.entry("poneyland") { *o.get_mut() += 10; assert_eq!(*o.get(), 22); // We can use the same Entry multiple times. *o.get_mut() += 2; } assert_eq!(map["poneyland"], 24);Run
ⓘImportant traits for &'_ mut Fpub fn into_mut(self) -> &'a mut V
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Converts the OccupiedEntry into a mutable reference to the value in the entry with a lifetime bound to the map itself.
If you need multiple references to the OccupiedEntry
, see get_mut
.
Examples
use std::collections::HashMap; use std::collections::hash_map::Entry; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); assert_eq!(map["poneyland"], 12); if let Entry::Occupied(o) = map.entry("poneyland") { *o.into_mut() += 10; } assert_eq!(map["poneyland"], 22);Run
pub fn insert(&mut self, value: V) -> V
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Sets the value of the entry, and returns the entry's old value.
Examples
use std::collections::HashMap; use std::collections::hash_map::Entry; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); if let Entry::Occupied(mut o) = map.entry("poneyland") { assert_eq!(o.insert(15), 12); } assert_eq!(map["poneyland"], 15);Run
pub fn remove(self) -> V
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Takes the value out of the entry, and returns it.
Examples
use std::collections::HashMap; use std::collections::hash_map::Entry; let mut map: HashMap<&str, u32> = HashMap::new(); map.entry("poneyland").or_insert(12); if let Entry::Occupied(o) = map.entry("poneyland") { assert_eq!(o.remove(), 12); } assert_eq!(map.contains_key("poneyland"), false);Run
pub fn replace_entry(self, value: V) -> (K, V)
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Replaces the entry, returning the old key and value. The new key in the hash map will be the key used to create this entry.
Examples
#![feature(map_entry_replace)] use std::collections::hash_map::{Entry, HashMap}; use std::rc::Rc; let mut map: HashMap<Rc<String>, u32> = HashMap::new(); map.insert(Rc::new("Stringthing".to_string()), 15); let my_key = Rc::new("Stringthing".to_string()); if let Entry::Occupied(entry) = map.entry(my_key) { // Also replace the key with a handle to our other key. let (old_key, old_value): (Rc<String>, u32) = entry.replace_entry(16); } Run
pub fn replace_key(self) -> K
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Replaces the key in the hash map with the key used to create this entry.
Examples
#![feature(map_entry_replace)] use std::collections::hash_map::{Entry, HashMap}; use std::rc::Rc; let mut map: HashMap<Rc<String>, u32> = HashMap::new(); let mut known_strings: Vec<Rc<String>> = Vec::new(); // Initialise known strings, run program, etc. reclaim_memory(&mut map, &known_strings); fn reclaim_memory(map: &mut HashMap<Rc<String>, u32>, known_strings: &[Rc<String>] ) { for s in known_strings { if let Entry::Occupied(entry) = map.entry(s.clone()) { // Replaces the entry's key with our version of it in `known_strings`. entry.replace_key(); } } }Run
Trait Implementations
impl<'_, K: Debug, V: Debug> Debug for OccupiedEntry<'_, K, V>
1.12.0[src]
Auto Trait Implementations
impl<'a, K, V> Send for OccupiedEntry<'a, K, V> where
K: Send,
V: Send,
K: Send,
V: Send,
impl<'a, K, V> Sync for OccupiedEntry<'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,
ⓘImportant traits for &'_ mut Ffn 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,