Struct gstd::prelude::collections::hash_map::OccupiedEntryRef
pub struct OccupiedEntryRef<'a, 'b, K, Q, V, S, A = Global>where
A: Allocator,
Q: ?Sized,{ /* private fields */ }
Expand description
A view into an occupied entry in a HashMap
.
It is part of the EntryRef
enum.
§Examples
use hashbrown::hash_map::{EntryRef, HashMap, OccupiedEntryRef};
let mut map = HashMap::new();
map.extend([("a".to_owned(), 10), ("b".into(), 20), ("c".into(), 30)]);
let key = String::from("a");
let _entry_o: OccupiedEntryRef<_, _, _, _> = map.entry_ref(&key).insert(100);
assert_eq!(map.len(), 3);
// Existing key (insert and update)
match map.entry_ref("a") {
EntryRef::Vacant(_) => unreachable!(),
EntryRef::Occupied(mut view) => {
assert_eq!(view.get(), &100);
let v = view.get_mut();
*v *= 10;
assert_eq!(view.insert(1111), 1000);
}
}
assert_eq!(map["a"], 1111);
assert_eq!(map.len(), 3);
// Existing key (take)
match map.entry_ref("c") {
EntryRef::Vacant(_) => unreachable!(),
EntryRef::Occupied(view) => {
assert_eq!(view.remove_entry(), ("c".to_owned(), 30));
}
}
assert_eq!(map.get("c"), None);
assert_eq!(map.len(), 2);
Implementations§
§impl<'a, 'b, K, Q, V, S, A> OccupiedEntryRef<'a, 'b, K, Q, V, S, A>where
A: Allocator,
Q: ?Sized,
impl<'a, 'b, K, Q, V, S, A> OccupiedEntryRef<'a, 'b, K, Q, V, S, A>where
A: Allocator,
Q: ?Sized,
pub fn key(&self) -> &K
pub fn key(&self) -> &K
Gets a reference to the key in the entry.
§Examples
use hashbrown::hash_map::{EntryRef, HashMap};
let mut map: HashMap<String, u32> = HashMap::new();
map.entry_ref("poneyland").or_insert(12);
match map.entry_ref("poneyland") {
EntryRef::Vacant(_) => panic!(),
EntryRef::Occupied(entry) => assert_eq!(entry.key(), "poneyland"),
}
pub fn remove_entry(self) -> (K, V)
pub fn remove_entry(self) -> (K, V)
Take the ownership of the key and value from the map. Keeps the allocated memory for reuse.
§Examples
use hashbrown::HashMap;
use hashbrown::hash_map::EntryRef;
let mut map: HashMap<String, u32> = HashMap::new();
// The map is empty
assert!(map.is_empty() && map.capacity() == 0);
map.entry_ref("poneyland").or_insert(12);
if let EntryRef::Occupied(o) = map.entry_ref("poneyland") {
// We delete the entry from the map.
assert_eq!(o.remove_entry(), ("poneyland".to_owned(), 12));
}
assert_eq!(map.contains_key("poneyland"), false);
// Now map hold none elements but capacity is equal to the old one
assert!(map.is_empty());
pub 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::EntryRef;
let mut map: HashMap<String, u32> = HashMap::new();
map.entry_ref("poneyland").or_insert(12);
match map.entry_ref("poneyland") {
EntryRef::Vacant(_) => panic!(),
EntryRef::Occupied(entry) => assert_eq!(entry.get(), &12),
}
pub 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 OccupiedEntryRef
which may outlive the
destruction of the EntryRef
value, see into_mut
.
§Examples
use hashbrown::HashMap;
use hashbrown::hash_map::EntryRef;
let mut map: HashMap<String, u32> = HashMap::new();
map.entry_ref("poneyland").or_insert(12);
assert_eq!(map["poneyland"], 12);
if let EntryRef::Occupied(mut o) = map.entry_ref("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);
pub fn into_mut(self) -> &'a mut V
pub fn into_mut(self) -> &'a mut V
Converts the OccupiedEntryRef 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 OccupiedEntryRef
, see get_mut
.
§Examples
use hashbrown::hash_map::{EntryRef, HashMap};
let mut map: HashMap<String, u32> = HashMap::new();
map.entry_ref("poneyland").or_insert(12);
let value: &mut u32;
match map.entry_ref("poneyland") {
EntryRef::Occupied(entry) => value = entry.into_mut(),
EntryRef::Vacant(_) => panic!(),
}
*value += 10;
assert_eq!(map["poneyland"], 22);
pub 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::EntryRef;
let mut map: HashMap<String, u32> = HashMap::new();
map.entry_ref("poneyland").or_insert(12);
if let EntryRef::Occupied(mut o) = map.entry_ref("poneyland") {
assert_eq!(o.insert(15), 12);
}
assert_eq!(map["poneyland"], 15);
pub fn remove(self) -> V
pub fn remove(self) -> V
Takes the value out of the entry, and returns it. Keeps the allocated memory for reuse.
§Examples
use hashbrown::HashMap;
use hashbrown::hash_map::EntryRef;
let mut map: HashMap<String, u32> = HashMap::new();
// The map is empty
assert!(map.is_empty() && map.capacity() == 0);
map.entry_ref("poneyland").or_insert(12);
if let EntryRef::Occupied(o) = map.entry_ref("poneyland") {
assert_eq!(o.remove(), 12);
}
assert_eq!(map.contains_key("poneyland"), false);
// Now map hold none elements but capacity is equal to the old one
assert!(map.is_empty());
pub 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 OccupiedEntryRef was created through EntryRef::insert
.
§Examples
use hashbrown::hash_map::{EntryRef, HashMap};
use std::rc::Rc;
let mut map: HashMap<Rc<str>, u32> = HashMap::new();
let key: Rc<str> = Rc::from("Stringthing");
map.insert(key.clone(), 15);
assert_eq!(Rc::strong_count(&key), 2);
match map.entry_ref("Stringthing") {
EntryRef::Occupied(entry) => {
let (old_key, old_value): (Rc<str>, u32) = entry.replace_entry(16);
assert!(Rc::ptr_eq(&key, &old_key) && old_value == 15);
}
EntryRef::Vacant(_) => panic!(),
}
assert_eq!(Rc::strong_count(&key), 1);
assert_eq!(map["Stringthing"], 16);
pub 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 OccupiedEntryRef was created through EntryRef::insert
.
§Examples
use hashbrown::hash_map::{EntryRef, HashMap};
use std::rc::Rc;
let mut map: HashMap<Rc<str>, usize> = HashMap::with_capacity(6);
let mut keys: Vec<Rc<str>> = Vec::with_capacity(6);
for (value, key) in ["a", "b", "c", "d", "e", "f"].into_iter().enumerate() {
let rc_key: Rc<str> = Rc::from(key);
keys.push(rc_key.clone());
map.insert(rc_key.clone(), value);
}
assert!(keys.iter().all(|key| Rc::strong_count(key) == 2));
// It doesn't matter that we kind of use a vector with the same keys,
// because all keys will be newly created from the references
reclaim_memory(&mut map, &keys);
assert!(keys.iter().all(|key| Rc::strong_count(key) == 1));
fn reclaim_memory(map: &mut HashMap<Rc<str>, usize>, keys: &[Rc<str>]) {
for key in keys {
if let EntryRef::Occupied(entry) = map.entry_ref(key.as_ref()) {
// Replaces the entry's key with our version of it in `keys`.
entry.replace_key();
}
}
}
pub fn replace_entry_with<F>(self, f: F) -> EntryRef<'a, 'b, K, Q, V, S, A>
pub fn replace_entry_with<F>(self, f: F) -> EntryRef<'a, 'b, K, Q, V, S, A>
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::EntryRef;
let mut map: HashMap<String, u32> = HashMap::new();
map.insert("poneyland".to_string(), 42);
let entry = match map.entry_ref("poneyland") {
EntryRef::Occupied(e) => {
e.replace_entry_with(|k, v| {
assert_eq!(k, "poneyland");
assert_eq!(v, 42);
Some(v + 1)
})
}
EntryRef::Vacant(_) => panic!(),
};
match entry {
EntryRef::Occupied(e) => {
assert_eq!(e.key(), "poneyland");
assert_eq!(e.get(), &43);
}
EntryRef::Vacant(_) => panic!(),
}
assert_eq!(map["poneyland"], 43);
let entry = match map.entry_ref("poneyland") {
EntryRef::Occupied(e) => e.replace_entry_with(|_k, _v| None),
EntryRef::Vacant(_) => panic!(),
};
match entry {
EntryRef::Vacant(e) => {
assert_eq!(e.key(), "poneyland");
}
EntryRef::Occupied(_) => panic!(),
}
assert!(!map.contains_key("poneyland"));
Trait Implementations§
§impl<K, Q, V, S, A> Debug for OccupiedEntryRef<'_, '_, K, Q, V, S, A>
impl<K, Q, V, S, A> Debug for OccupiedEntryRef<'_, '_, K, Q, V, S, A>
impl<'a, 'b, K, Q, V, S, A> Send for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>
impl<'a, 'b, K, Q, V, S, A> Sync for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>
Auto Trait Implementations§
impl<'a, 'b, K, Q: ?Sized, V, S, A> RefUnwindSafe for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>
impl<'a, 'b, K, Q: ?Sized, V, S, A> Unpin for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>where
K: Unpin,
impl<'a, 'b, K, Q, V, S, A = Global> !UnwindSafe for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>
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
§impl<T> Conv for T
impl<T> Conv for T
§impl<T> FmtForward for T
impl<T> FmtForward for T
§fn fmt_binary(self) -> FmtBinary<Self>where
Self: Binary,
fn fmt_binary(self) -> FmtBinary<Self>where
Self: Binary,
self
to use its Binary
implementation when Debug
-formatted.§fn fmt_display(self) -> FmtDisplay<Self>where
Self: Display,
fn fmt_display(self) -> FmtDisplay<Self>where
Self: Display,
self
to use its Display
implementation when
Debug
-formatted.§fn fmt_lower_exp(self) -> FmtLowerExp<Self>where
Self: LowerExp,
fn fmt_lower_exp(self) -> FmtLowerExp<Self>where
Self: LowerExp,
self
to use its LowerExp
implementation when
Debug
-formatted.§fn fmt_lower_hex(self) -> FmtLowerHex<Self>where
Self: LowerHex,
fn fmt_lower_hex(self) -> FmtLowerHex<Self>where
Self: LowerHex,
self
to use its LowerHex
implementation when
Debug
-formatted.§fn fmt_octal(self) -> FmtOctal<Self>where
Self: Octal,
fn fmt_octal(self) -> FmtOctal<Self>where
Self: Octal,
self
to use its Octal
implementation when Debug
-formatted.§fn fmt_pointer(self) -> FmtPointer<Self>where
Self: Pointer,
fn fmt_pointer(self) -> FmtPointer<Self>where
Self: Pointer,
self
to use its Pointer
implementation when
Debug
-formatted.§fn fmt_upper_exp(self) -> FmtUpperExp<Self>where
Self: UpperExp,
fn fmt_upper_exp(self) -> FmtUpperExp<Self>where
Self: UpperExp,
self
to use its UpperExp
implementation when
Debug
-formatted.§fn fmt_upper_hex(self) -> FmtUpperHex<Self>where
Self: UpperHex,
fn fmt_upper_hex(self) -> FmtUpperHex<Self>where
Self: UpperHex,
self
to use its UpperHex
implementation when
Debug
-formatted.§fn fmt_list(self) -> FmtList<Self>where
&'a Self: for<'a> IntoIterator,
fn fmt_list(self) -> FmtList<Self>where
&'a Self: for<'a> IntoIterator,
§impl<T> Pipe for Twhere
T: ?Sized,
impl<T> Pipe for Twhere
T: ?Sized,
§fn pipe<R>(self, func: impl FnOnce(Self) -> R) -> Rwhere
Self: Sized,
fn pipe<R>(self, func: impl FnOnce(Self) -> R) -> Rwhere
Self: Sized,
§fn pipe_ref<'a, R>(&'a self, func: impl FnOnce(&'a Self) -> R) -> Rwhere
R: 'a,
fn pipe_ref<'a, R>(&'a self, func: impl FnOnce(&'a Self) -> R) -> Rwhere
R: 'a,
self
and passes that borrow into the pipe function. Read more§fn pipe_ref_mut<'a, R>(&'a mut self, func: impl FnOnce(&'a mut Self) -> R) -> Rwhere
R: 'a,
fn pipe_ref_mut<'a, R>(&'a mut self, func: impl FnOnce(&'a mut Self) -> R) -> Rwhere
R: 'a,
self
and passes that borrow into the pipe function. Read more§fn pipe_borrow<'a, B, R>(&'a self, func: impl FnOnce(&'a B) -> R) -> R
fn pipe_borrow<'a, B, R>(&'a self, func: impl FnOnce(&'a B) -> R) -> R
§fn pipe_borrow_mut<'a, B, R>(
&'a mut self,
func: impl FnOnce(&'a mut B) -> R
) -> R
fn pipe_borrow_mut<'a, B, R>( &'a mut self, func: impl FnOnce(&'a mut B) -> R ) -> R
§fn pipe_as_ref<'a, U, R>(&'a self, func: impl FnOnce(&'a U) -> R) -> R
fn pipe_as_ref<'a, U, R>(&'a self, func: impl FnOnce(&'a U) -> R) -> R
self
, then passes self.as_ref()
into the pipe function.§fn pipe_as_mut<'a, U, R>(&'a mut self, func: impl FnOnce(&'a mut U) -> R) -> R
fn pipe_as_mut<'a, U, R>(&'a mut self, func: impl FnOnce(&'a mut U) -> R) -> R
self
, then passes self.as_mut()
into the pipe
function.§fn pipe_deref<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R
fn pipe_deref<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R
self
, then passes self.deref()
into the pipe function.§impl<T> Tap for T
impl<T> Tap for T
§fn tap_borrow<B>(self, func: impl FnOnce(&B)) -> Self
fn tap_borrow<B>(self, func: impl FnOnce(&B)) -> Self
Borrow<B>
of a value. Read more§fn tap_borrow_mut<B>(self, func: impl FnOnce(&mut B)) -> Self
fn tap_borrow_mut<B>(self, func: impl FnOnce(&mut B)) -> Self
BorrowMut<B>
of a value. Read more§fn tap_ref<R>(self, func: impl FnOnce(&R)) -> Self
fn tap_ref<R>(self, func: impl FnOnce(&R)) -> Self
AsRef<R>
view of a value. Read more§fn tap_ref_mut<R>(self, func: impl FnOnce(&mut R)) -> Self
fn tap_ref_mut<R>(self, func: impl FnOnce(&mut R)) -> Self
AsMut<R>
view of a value. Read more§fn tap_deref<T>(self, func: impl FnOnce(&T)) -> Self
fn tap_deref<T>(self, func: impl FnOnce(&T)) -> Self
Deref::Target
of a value. Read more§fn tap_deref_mut<T>(self, func: impl FnOnce(&mut T)) -> Self
fn tap_deref_mut<T>(self, func: impl FnOnce(&mut T)) -> Self
Deref::Target
of a value. Read more§fn tap_dbg(self, func: impl FnOnce(&Self)) -> Self
fn tap_dbg(self, func: impl FnOnce(&Self)) -> Self
.tap()
only in debug builds, and is erased in release builds.§fn tap_mut_dbg(self, func: impl FnOnce(&mut Self)) -> Self
fn tap_mut_dbg(self, func: impl FnOnce(&mut Self)) -> Self
.tap_mut()
only in debug builds, and is erased in release
builds.§fn tap_borrow_dbg<B>(self, func: impl FnOnce(&B)) -> Self
fn tap_borrow_dbg<B>(self, func: impl FnOnce(&B)) -> Self
.tap_borrow()
only in debug builds, and is erased in release
builds.§fn tap_borrow_mut_dbg<B>(self, func: impl FnOnce(&mut B)) -> Self
fn tap_borrow_mut_dbg<B>(self, func: impl FnOnce(&mut B)) -> Self
.tap_borrow_mut()
only in debug builds, and is erased in release
builds.§fn tap_ref_dbg<R>(self, func: impl FnOnce(&R)) -> Self
fn tap_ref_dbg<R>(self, func: impl FnOnce(&R)) -> Self
.tap_ref()
only in debug builds, and is erased in release
builds.§fn tap_ref_mut_dbg<R>(self, func: impl FnOnce(&mut R)) -> Self
fn tap_ref_mut_dbg<R>(self, func: impl FnOnce(&mut R)) -> Self
.tap_ref_mut()
only in debug builds, and is erased in release
builds.§fn tap_deref_dbg<T>(self, func: impl FnOnce(&T)) -> Self
fn tap_deref_dbg<T>(self, func: impl FnOnce(&T)) -> Self
.tap_deref()
only in debug builds, and is erased in release
builds.