Struct hashbrown::hash_map::OccupiedEntry
source · [−]pub struct OccupiedEntry<'a, K, V, S, A: Allocator + Clone = Global> { /* private fields */ }
Expand description
A view into an occupied entry in a HashMap
.
It is part of the Entry
enum.
Implementations
sourceimpl<'a, K, V, S, A: Allocator + Clone> OccupiedEntry<'a, K, V, S, A>
impl<'a, K, V, S, A: Allocator + Clone> OccupiedEntry<'a, K, V, S, A>
sourcepub fn key(&self) -> &K
pub fn key(&self) -> &K
Gets a reference to the key in the entry.
Examples
use hashbrown::HashMap;
let mut map: HashMap<&str, u32> = HashMap::new();
map.entry("poneyland").or_insert(12);
assert_eq!(map.entry("poneyland").key(), &"poneyland");
sourcepub fn remove_entry(self) -> (K, V)
pub fn remove_entry(self) -> (K, V)
Take the ownership of the key and value from the map.
Examples
use hashbrown::HashMap;
use hashbrown::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);
sourcepub fn get(&self) -> &V
pub fn get(&self) -> &V
Gets a reference to the value in the entry.
Examples
use hashbrown::HashMap;
use hashbrown::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);
}
sourcepub fn get_mut(&mut self) -> &mut V
pub fn get_mut(&mut self) -> &mut V
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 hashbrown::HashMap;
use hashbrown::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);
sourcepub fn into_mut(self) -> &'a mut V
pub fn into_mut(self) -> &'a mut V
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 hashbrown::HashMap;
use hashbrown::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);
sourcepub fn insert(&mut self, value: V) -> V
pub fn insert(&mut self, value: V) -> V
Sets the value of the entry, and returns the entry’s old value.
Examples
use hashbrown::HashMap;
use hashbrown::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);
sourcepub fn remove(self) -> V
pub fn remove(self) -> V
Takes the value out of the entry, and returns it.
Examples
use hashbrown::HashMap;
use hashbrown::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);
sourcepub fn replace_entry(self, value: V) -> (K, V)
pub fn replace_entry(self, value: V) -> (K, V)
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.
Panics
Will panic if this OccupiedEntry was created through Entry::insert
.
Examples
use hashbrown::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);
}
sourcepub fn replace_key(self) -> K
pub fn replace_key(self) -> K
Replaces the key in the hash map with the key used to create this entry.
Panics
Will panic if this OccupiedEntry was created through Entry::insert
.
Examples
use hashbrown::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();
}
}
}
sourcepub fn replace_entry_with<F>(self, f: F) -> Entry<'a, K, V, S, A> where
F: FnOnce(&K, V) -> Option<V>,
pub fn replace_entry_with<F>(self, f: F) -> Entry<'a, K, V, S, A> where
F: FnOnce(&K, V) -> Option<V>,
Provides shared access to the key and owned access to the value of the entry and allows to replace or remove it based on the value of the returned option.
Examples
use hashbrown::HashMap;
use hashbrown::hash_map::Entry;
let mut map: HashMap<&str, u32> = HashMap::new();
map.insert("poneyland", 42);
let entry = match map.entry("poneyland") {
Entry::Occupied(e) => {
e.replace_entry_with(|k, v| {
assert_eq!(k, &"poneyland");
assert_eq!(v, 42);
Some(v + 1)
})
}
Entry::Vacant(_) => panic!(),
};
match entry {
Entry::Occupied(e) => {
assert_eq!(e.key(), &"poneyland");
assert_eq!(e.get(), &43);
}
Entry::Vacant(_) => panic!(),
}
assert_eq!(map["poneyland"], 43);
let entry = match map.entry("poneyland") {
Entry::Occupied(e) => e.replace_entry_with(|_k, _v| None),
Entry::Vacant(_) => panic!(),
};
match entry {
Entry::Vacant(e) => {
assert_eq!(e.key(), &"poneyland");
}
Entry::Occupied(_) => panic!(),
}
assert!(!map.contains_key("poneyland"));
Trait Implementations
impl<K, V, S, A> Send for OccupiedEntry<'_, K, V, S, A> where
K: Send,
V: Send,
S: Send,
A: Send + Allocator + Clone,
impl<K, V, S, A> Sync for OccupiedEntry<'_, K, V, S, A> where
K: Sync,
V: Sync,
S: Sync,
A: Sync + Allocator + Clone,
Auto Trait Implementations
impl<'a, K, V, S, A> RefUnwindSafe for OccupiedEntry<'a, K, V, S, A> where
A: RefUnwindSafe,
K: RefUnwindSafe,
S: RefUnwindSafe,
V: RefUnwindSafe,
impl<'a, K, V, S, A> Unpin for OccupiedEntry<'a, K, V, S, A> where
K: Unpin,
impl<'a, K, V, S, A = Global> !UnwindSafe for OccupiedEntry<'a, K, V, S, A>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more