Enum gstd::prelude::collections::hash_set::Entry

pub enum Entry<'a, T, S, A = Global>
where
    A: Allocator,
{
    Occupied(OccupiedEntry<'a, T, S, A>),
    Vacant(VacantEntry<'a, T, S, A>),
}

A view into a single entry in a set, which may either be vacant or occupied.

This enum is constructed from the entry method on HashSet.

Examples

use hashbrown::hash_set::{Entry, HashSet, OccupiedEntry};

let mut set = HashSet::new();
set.extend(["a", "b", "c"]);
assert_eq!(set.len(), 3);

// Existing value (insert)
let entry: Entry<_, _> = set.entry("a");
let _raw_o: OccupiedEntry<_, _> = entry.insert();
assert_eq!(set.len(), 3);
// Nonexistent value (insert)
set.entry("d").insert();

// Existing value (or_insert)
set.entry("b").or_insert();
// Nonexistent value (or_insert)
set.entry("e").or_insert();

println!("Our HashSet: {:?}", set);

let mut vec: Vec<_> = set.iter().copied().collect();
// The `Iter` iterator produces items in arbitrary order, so the
// items must be sorted to test them against a sorted array.
vec.sort_unstable();
assert_eq!(vec, ["a", "b", "c", "d", "e"]);

Variants

Occupied(OccupiedEntry<'a, T, S, A>)

An occupied entry.

Examples

use hashbrown::hash_set::{Entry, HashSet};
let mut set: HashSet<_> = ["a", "b"].into();

match set.entry("a") {
    Entry::Vacant(_) => unreachable!(),
    Entry::Occupied(_) => { }
}

Vacant(VacantEntry<'a, T, S, A>)

A vacant entry.

Examples

use hashbrown::hash_set::{Entry, HashSet};
let mut set: HashSet<&str> = HashSet::new();

match set.entry("a") {
    Entry::Occupied(_) => unreachable!(),
    Entry::Vacant(_) => { }
}

Implementations

impl<'a, T, S, A> Entry<'a, T, S, A>

where A: Allocator,

pub fn insert(self) -> OccupiedEntry<'a, T, S, A>

where T: Hash, S: BuildHasher,

Sets the value of the entry, and returns an OccupiedEntry.

Examples

use hashbrown::HashSet;

let mut set: HashSet<&str> = HashSet::new();
let entry = set.entry("horseyland").insert();

assert_eq!(entry.get(), &"horseyland");

pub fn or_insert(self)

where T: Hash, S: BuildHasher,

Ensures a value is in the entry by inserting if it was vacant.

Examples

use hashbrown::HashSet;

let mut set: HashSet<&str> = HashSet::new();

// nonexistent key
set.entry("poneyland").or_insert();
assert!(set.contains("poneyland"));

// existing key
set.entry("poneyland").or_insert();
assert!(set.contains("poneyland"));
assert_eq!(set.len(), 1);

pub fn get(&self) -> &T

Returns a reference to this entry’s value.

Examples

use hashbrown::HashSet;

let mut set: HashSet<&str> = HashSet::new();
set.entry("poneyland").or_insert();
// existing key
assert_eq!(set.entry("poneyland").get(), &"poneyland");
// nonexistent key
assert_eq!(set.entry("horseland").get(), &"horseland");

Trait Implementations

impl<T, S, A> Debug for Entry<'_, T, S, A>

where T: Debug, A: Allocator,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.