Enum halfbrown::RawEntryMut

pub enum RawEntryMut<'map, K, V, S> {
    Occupied(RawOccupiedEntryMut<'map, K, V, S>),
    Vacant(RawVacantEntryMut<'map, K, V, S>),
}

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

This is a lower-level version of Entry.

This enum is constructed through the raw_entry_mut method on HashMap, then calling one of the methods of that RawEntryBuilderMut.

Variants

Occupied(RawOccupiedEntryMut<'map, K, V, S>)

An occupied entry.

Vacant(RawVacantEntryMut<'map, K, V, S>)

A vacant entry.

Implementations

impl<'map, K, V, S> RawEntryMut<'map, K, V, S> where
    S: BuildHasher, 

pub fn insert(self, key: K, value: V) -> RawOccupiedEntryMut<'map, K, V, S> where
    K: Hash,
    S: BuildHasher, 

Sets the value of the entry, and returns a RawOccupiedEntryMut.

Examples

use hashbrown::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
let entry = map.raw_entry_mut().from_key("horseyland").insert("horseyland", 37);

assert_eq!(entry.remove_entry(), ("horseyland", 37));

pub fn or_insert(
    self,
    default_key: K,
    default_val: V
) -> (&'map mut K, &'map mut V) where
    K: Hash,
    S: BuildHasher, 

Ensures a value is in the entry by inserting the default if empty, and returns mutable references to the key and value in the entry.

Examples

use hashbrown::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 3);
assert_eq!(map["poneyland"], 3);

*map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 10).1 *= 2;
assert_eq!(map["poneyland"], 6);

pub fn or_insert_with<F>(self, default: F) -> (&'map mut K, &'map mut V) where
    F: FnOnce() -> (K, V),
    K: Hash,
    S: BuildHasher, 

Ensures a value is in the entry by inserting the result of the default function if empty, and returns mutable references to the key and value in the entry.

Examples

use hashbrown::HashMap;

let mut map: HashMap<&str, String> = HashMap::new();

map.raw_entry_mut().from_key("poneyland").or_insert_with(|| {
    ("poneyland", "hoho".to_string())
});

assert_eq!(map["poneyland"], "hoho".to_string());

pub fn and_modify<F>(self, f: F) -> Self where
    F: FnOnce(&mut K, &mut V), 

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

Examples

use hashbrown::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.raw_entry_mut()
   .from_key("poneyland")
   .and_modify(|_k, v| { *v += 1 })
   .or_insert("poneyland", 42);
assert_eq!(map["poneyland"], 42);

map.raw_entry_mut()
   .from_key("poneyland")
   .and_modify(|_k, v| { *v += 1 })
   .or_insert("poneyland", 0);
assert_eq!(map["poneyland"], 43);

Trait Implementations

impl<K: Debug, V: Debug, S> Debug for RawEntryMut<'_, K, V, S> where
    S: BuildHasher, 

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

Formats the value using the given formatter.

impl<'map, K, V, S> From<RawEntryMut<'map, K, V, S, Global>> for RawEntryMut<'map, K, V, S>

fn from(e: RawEntryMut<'map, K, V, S>) -> Self

Converts to this type from the input type.