Struct VacantEntry

pub struct VacantEntry<'a, K, V> { /* private fields */ }

A view into a vacant entry in an IndexMap. It is part of the Entry enum.

Implementations

impl<'a, K, V> VacantEntry<'a, K, V>

pub fn index(&self) -> usize

Return the index where a key-value pair may be inserted.

pub fn key(&self) -> &K

Gets a reference to the key that was used to find the entry.

pub fn into_key(self) -> K

Takes ownership of the key, leaving the entry vacant.

pub fn insert(self, value: V) -> &'a mut V

Inserts the entry’s key and the given value into the map, and returns a mutable reference to the value.

Computes in O(1) time (amortized average).

pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V>

Inserts the entry’s key and the given value into the map, and returns an OccupiedEntry.

Computes in O(1) time (amortized average).

pub fn insert_sorted(self, value: V) -> (usize, &'a mut V)

where K: Ord,

Inserts the entry’s key and the given value into the map at its ordered position among sorted keys, and returns the new index and a mutable reference to the value.

If the existing keys are not already sorted, then the insertion index is unspecified (like slice::binary_search), but the key-value pair is inserted at that position regardless.

Computes in O(n) time (average).

pub fn insert_sorted_by<F>(self, value: V, cmp: F) -> (usize, &'a mut V)

where K: Ord, F: FnMut(&K, &V, &K, &V) -> Ordering,

Inserts the entry’s key and the given value into the map at its ordered position among keys sorted by cmp, and returns the new index and a mutable reference to the value.

If the existing keys are not already sorted, then the insertion index is unspecified (like slice::binary_search), but the key-value pair is inserted at that position regardless.

Computes in O(n) time (average).

pub fn insert_sorted_by_key<B, F>( self, value: V, sort_key: F, ) -> (usize, &'a mut V)

where B: Ord, F: FnMut(&K, &V) -> B,

Inserts the entry’s key and the given value into the map at its ordered position using a sort-key extraction function, and returns the new index and a mutable reference to the value.

If the existing keys are not already sorted, then the insertion index is unspecified (like slice::binary_search), but the key-value pair is inserted at that position regardless.

Computes in O(n) time (average).

pub fn shift_insert(self, index: usize, value: V) -> &'a mut V

Inserts the entry’s key and the given value into the map at the given index, shifting others to the right, and returns a mutable reference to the value.

Panics if index is out of bounds.

Computes in O(n) time (average).

pub fn replace_index(self, index: usize) -> (K, OccupiedEntry<'a, K, V>)

Replaces the key at the given index with this entry’s key, returning the old key and an OccupiedEntry for that index.

Panics if index is out of bounds.

Computes in O(1) time (average).

Trait Implementations

impl<K, V> Debug for VacantEntry<'_, K, V>

where K: Debug,

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

Formats the value using the given formatter.

impl<K, V> MutableEntryKey for VacantEntry<'_, K, V>

Opt-in mutable access to VacantEntry keys.

See MutableEntryKey for more information.

type Key = K

fn key_mut(&mut self) -> &mut <VacantEntry<'_, K, V> as MutableEntryKey>::Key

Gets a mutable reference to the entry’s key, either within the map if occupied, or else the new key that was used to find the entry.