Struct hashbrown::hash_table::VacantEntry
source · pub struct VacantEntry<'a, T, A = Global>where
A: Allocator,{ /* private fields */ }
Expand description
A view into a vacant entry in a HashTable
.
It is part of the Entry
enum.
§Examples
use hashbrown::hash_table::{Entry, VacantEntry};
use hashbrown::{HashTable, DefaultHashBuilder};
use std::hash::BuildHasher;
let mut table: HashTable<&str> = HashTable::new();
let hasher = DefaultHashBuilder::default();
let hasher = |val: &_| hasher.hash_one(val);
let entry_v: VacantEntry<_, _> = match table.entry(hasher(&"a"), |&x| x == "a", hasher) {
Entry::Vacant(view) => view,
Entry::Occupied(_) => unreachable!(),
};
entry_v.insert("a");
assert!(table.find(hasher(&"a"), |&x| x == "a").is_some() && table.len() == 1);
// Nonexistent key (insert)
match table.entry(hasher(&"b"), |&x| x == "b", hasher) {
Entry::Vacant(view) => {
view.insert("b");
}
Entry::Occupied(_) => unreachable!(),
}
assert!(table.find(hasher(&"b"), |&x| x == "b").is_some() && table.len() == 2);
Implementations§
source§impl<'a, T, A> VacantEntry<'a, T, A>where
A: Allocator,
impl<'a, T, A> VacantEntry<'a, T, A>where
A: Allocator,
sourcepub fn insert(self, value: T) -> OccupiedEntry<'a, T, A>
pub fn insert(self, value: T) -> OccupiedEntry<'a, T, A>
Inserts a new element into the table with the hash that was used to
obtain the VacantEntry
.
An OccupiedEntry
is returned for the newly inserted element.
§Examples
use hashbrown::hash_table::Entry;
use hashbrown::{HashTable, DefaultHashBuilder};
use std::hash::BuildHasher;
let mut table: HashTable<&str> = HashTable::new();
let hasher = DefaultHashBuilder::default();
let hasher = |val: &_| hasher.hash_one(val);
if let Entry::Vacant(o) = table.entry(hasher(&"poneyland"), |&x| x == "poneyland", hasher) {
o.insert("poneyland");
}
assert_eq!(
table.find(hasher(&"poneyland"), |&x| x == "poneyland"),
Some(&"poneyland")
);
sourcepub fn into_table(self) -> &'a mut HashTable<T, A>
pub fn into_table(self) -> &'a mut HashTable<T, A>
Converts the VacantEntry
into a mutable reference to the underlying
table.
Trait Implementations§
Auto Trait Implementations§
impl<'a, T, A> Freeze for VacantEntry<'a, T, A>
impl<'a, T, A> RefUnwindSafe for VacantEntry<'a, T, A>where
A: RefUnwindSafe,
T: RefUnwindSafe,
impl<'a, T, A> Send for VacantEntry<'a, T, A>
impl<'a, T, A> Sync for VacantEntry<'a, T, A>
impl<'a, T, A> Unpin for VacantEntry<'a, T, A>
impl<'a, T, A = Global> !UnwindSafe for VacantEntry<'a, T, 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
Mutably borrows from an owned value. Read more