pub struct IndexMap<K, V, S = RandomState> { /* private fields */ }
Expand description
A hash table where the iteration order of the key-value pairs is independent of the hash values of the keys.
The interface is closely compatible with the standard HashMap
, but also
has additional features.
§Order
The key-value pairs have a consistent order that is determined by the sequence of insertion and removal calls on the map. The order does not depend on the keys or the hash function at all.
All iterators traverse the map in the order.
The insertion order is preserved, with notable exceptions like the
.remove()
or .swap_remove()
methods. Methods such as .sort_by()
of
course result in a new order, depending on the sorting order.
§Indices
The key-value pairs are indexed in a compact range without holes in the
range 0..self.len()
. For example, the method .get_full
looks up the
index for a key, and the method .get_index
looks up the key-value pair by
index.
§Examples
use discord_indexmap::IndexMap;
// count the frequency of each letter in a sentence.
let mut letters = IndexMap::new();
for ch in "a short treatise on fungi".chars() {
*letters.entry(ch).or_insert(0) += 1;
}
assert_eq!(letters[&'s'], 2);
assert_eq!(letters[&'t'], 3);
assert_eq!(letters[&'u'], 1);
assert_eq!(letters.get(&'y'), None);
Implementations§
Source§impl<K, V> IndexMap<K, V>
impl<K, V> IndexMap<K, V>
Sourcepub fn with_capacity(n: usize) -> Self
pub fn with_capacity(n: usize) -> Self
Create a new map with capacity for n
key-value pairs. (Does not
allocate if n
is zero.)
Computes in O(n) time.
Source§impl<K, V, S> IndexMap<K, V, S>
impl<K, V, S> IndexMap<K, V, S>
Sourcepub fn with_capacity_and_hasher(n: usize, hash_builder: S) -> Selfwhere
S: BuildHasher,
pub fn with_capacity_and_hasher(n: usize, hash_builder: S) -> Selfwhere
S: BuildHasher,
Create a new map with capacity for n
key-value pairs. (Does not
allocate if n
is zero.)
Computes in O(n) time.
Sourcepub fn len(&self) -> usize
pub fn len(&self) -> usize
Return the number of key-value pairs in the map.
Computes in O(1) time.
Sourcepub fn is_empty(&self) -> bool
pub fn is_empty(&self) -> bool
Returns true if the map contains no elements.
Computes in O(1) time.
Sourcepub fn with_hasher(hash_builder: S) -> Selfwhere
S: BuildHasher,
pub fn with_hasher(hash_builder: S) -> Selfwhere
S: BuildHasher,
Create a new map with hash_builder
Sourcepub fn hasher(&self) -> &Swhere
S: BuildHasher,
pub fn hasher(&self) -> &Swhere
S: BuildHasher,
Return a reference to the map’s BuildHasher
.
Source§impl<K, V, S> IndexMap<K, V, S>
impl<K, V, S> IndexMap<K, V, S>
Sourcepub fn clear(&mut self)
pub fn clear(&mut self)
Remove all key-value pairs in the map, while preserving its capacity.
Computes in O(n) time.
Sourcepub fn reserve(&mut self, additional: usize)
pub fn reserve(&mut self, additional: usize)
Reserve capacity for additional
more key-value pairs.
FIXME Not implemented fully yet.
Sourcepub fn insert(&mut self, key: K, value: V) -> Option<V>
pub fn insert(&mut self, key: K, value: V) -> Option<V>
Insert a key-value pair in the map.
If an equivalent key already exists in the map: the key remains and
retains in its place in the order, its corresponding value is updated
with value
and the older value is returned inside Some(_)
.
If no equivalent key existed in the map: the new key-value pair is
inserted, last in order, and None
is returned.
Computes in O(1) time (amortized average).
See also entry
if you you want to insert or modify
or if you need to get the index of the corresponding key-value pair.
Sourcepub fn insert_full(&mut self, key: K, value: V) -> (usize, Option<V>)
pub fn insert_full(&mut self, key: K, value: V) -> (usize, Option<V>)
Insert a key-value pair in the map, and get their index.
If an equivalent key already exists in the map: the key remains and
retains in its place in the order, its corresponding value is updated
with value
and the older value is returned inside (index, Some(_))
.
If no equivalent key existed in the map: the new key-value pair is
inserted, last in order, and (index, None)
is returned.
Computes in O(1) time (amortized average).
See also entry
if you you want to insert or modify
or if you need to get the index of the corresponding key-value pair.
Sourcepub fn entry(&mut self, key: K) -> Entry<'_, K, V>
pub fn entry(&mut self, key: K) -> Entry<'_, K, V>
Get the given key’s corresponding entry in the map for insertion and/or in-place manipulation.
Computes in O(1) time (amortized average).
Sourcepub fn iter(&self) -> Iter<'_, K, V> ⓘ
pub fn iter(&self) -> Iter<'_, K, V> ⓘ
Return an iterator over the key-value pairs of the map, in their order
Sourcepub fn iter_mut(&mut self) -> IterMut<'_, K, V> ⓘ
pub fn iter_mut(&mut self) -> IterMut<'_, K, V> ⓘ
Return an iterator over the key-value pairs of the map, in their order
Sourcepub fn keys(&self) -> Keys<'_, K, V> ⓘ
pub fn keys(&self) -> Keys<'_, K, V> ⓘ
Return an iterator over the keys of the map, in their order
Sourcepub fn values(&self) -> Values<'_, K, V> ⓘ
pub fn values(&self) -> Values<'_, K, V> ⓘ
Return an iterator over the values of the map, in their order
Sourcepub fn values_mut(&mut self) -> ValuesMut<'_, K, V> ⓘ
pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> ⓘ
Return an iterator over mutable references to the the values of the map, in their order
Sourcepub fn contains_key<Q>(&self, key: &Q) -> bool
pub fn contains_key<Q>(&self, key: &Q) -> bool
Return true
if an equivalent to key
exists in the map.
Computes in O(1) time (average).
Sourcepub fn get<Q>(&self, key: &Q) -> Option<&V>
pub fn get<Q>(&self, key: &Q) -> Option<&V>
Return a reference to the value stored for key
, if it is present,
else None
.
Computes in O(1) time (average).
Sourcepub fn entry_index<Q>(&self, key: &Q) -> Option<usize>
pub fn entry_index<Q>(&self, key: &Q) -> Option<usize>
Return item index
pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut V>
pub fn get_full_mut<Q>(&mut self, key: &Q) -> Option<(usize, &K, &mut V)>
Sourcepub fn remove<Q>(&mut self, key: &Q) -> Option<V>
pub fn remove<Q>(&mut self, key: &Q) -> Option<V>
Remove the key-value pair equivalent to key
and return
its value.
NOTE: This is equivalent to .swap_remove(key)
, if you need to
preserve the order of the keys in the map, use .shift_remove(key)
instead.
Computes in O(1) time (average).
Sourcepub fn swap_remove<Q>(&mut self, key: &Q) -> Option<V>
pub fn swap_remove<Q>(&mut self, key: &Q) -> Option<V>
Remove the key-value pair equivalent to key
and return
its value.
Like Vec::swap_remove
, the pair is removed by swapping it with the
last element of the map and popping it off. This perturbs
the postion of what used to be the last element!
Return None
if key
is not in map.
Computes in O(1) time (average).
Sourcepub fn swap_remove_full<Q>(&mut self, key: &Q) -> Option<(usize, K, V)>
pub fn swap_remove_full<Q>(&mut self, key: &Q) -> Option<(usize, K, V)>
Remove the key-value pair equivalent to key
and return it and
the index it had.
Like Vec::swap_remove
, the pair is removed by swapping it with the
last element of the map and popping it off. This perturbs
the postion of what used to be the last element!
Return None
if key
is not in map.
Computes in O(1) time (average).
Sourcepub fn shift_remove<Q>(&mut self, key: &Q) -> Option<V>
pub fn shift_remove<Q>(&mut self, key: &Q) -> Option<V>
Remove the key-value pair equivalent to key
and return
its value.
Like Vec::remove
, the pair is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Return None
if key
is not in map.
Computes in O(n) time (average).
Sourcepub fn shift_remove_full<Q>(&mut self, key: &Q) -> Option<(usize, K, V)>
pub fn shift_remove_full<Q>(&mut self, key: &Q) -> Option<(usize, K, V)>
Remove the key-value pair equivalent to key
and return it and
the index it had.
Like Vec::remove
, the pair is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Return None
if key
is not in map.
Computes in O(n) time (average).
Sourcepub fn pop(&mut self) -> Option<(K, V)>
pub fn pop(&mut self) -> Option<(K, V)>
Remove the last key-value pair
Computes in O(1) time (average).
Sourcepub fn retain<F>(&mut self, keep: F)
pub fn retain<F>(&mut self, keep: F)
Scan through each key-value pair in the map and keep those where the
closure keep
returns true
.
The elements are visited in order, and remaining elements keep their order.
Computes in O(n) time (average).
Sourcepub fn sort_keys(&mut self)where
K: Ord,
pub fn sort_keys(&mut self)where
K: Ord,
Sort the map’s key-value pairs by the default ordering of the keys.
See sort_by
for details.
Sourcepub fn sort_by<F>(&mut self, compare: F)
pub fn sort_by<F>(&mut self, compare: F)
Sort the map’s key-value pairs in place using the comparison
function compare
.
The comparison function receives two key and value pairs to compare (you can sort by keys or values or their combination as needed).
Computes in O(n log n + c) time and O(n) space where n is the length of the map and c the capacity. The sort is stable.
Source§impl<K, V, S> IndexMap<K, V, S>
impl<K, V, S> IndexMap<K, V, S>
Sourcepub fn get_index(&self, index: usize) -> Option<(&K, &V)>
pub fn get_index(&self, index: usize) -> Option<(&K, &V)>
Get a key-value pair by index
Valid indices are 0 <= index < self.len()
Computes in O(1) time.
Sourcepub fn get_index_mut(&mut self, index: usize) -> Option<(&mut K, &mut V)>
pub fn get_index_mut(&mut self, index: usize) -> Option<(&mut K, &mut V)>
Get a key-value pair by index
Valid indices are 0 <= index < self.len()
Computes in O(1) time.
Sourcepub fn swap_remove_index(&mut self, index: usize) -> Option<(K, V)>
pub fn swap_remove_index(&mut self, index: usize) -> Option<(K, V)>
Remove the key-value pair by index
Valid indices are 0 <= index < self.len()
Like Vec::swap_remove
, the pair is removed by swapping it with the
last element of the map and popping it off. This perturbs
the postion of what used to be the last element!
Computes in O(1) time (average).
Sourcepub fn shift_remove_index(&mut self, index: usize) -> Option<(K, V)>
pub fn shift_remove_index(&mut self, index: usize) -> Option<(K, V)>
Remove the key-value pair by index
Valid indices are 0 <= index < self.len()
Like Vec::remove
, the pair is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Computes in O(n) time (average).
Source§impl<K, V, S> IndexMap<K, V, S>
Parallel iterator methods and other parallel methods.
impl<K, V, S> IndexMap<K, V, S>
Parallel iterator methods and other parallel methods.
The following methods require crate feature "rayon"
.
See also the IntoParallelIterator
implementations.
Sourcepub fn par_keys(&self) -> ParKeys<'_, K, V>
pub fn par_keys(&self) -> ParKeys<'_, K, V>
Return a parallel iterator over the keys of the map.
While parallel iterators can process items in any order, their relative order
in the map is still preserved for operations like reduce
and collect
.
Sourcepub fn par_values(&self) -> ParValues<'_, K, V>
pub fn par_values(&self) -> ParValues<'_, K, V>
Return a parallel iterator over the values of the map.
While parallel iterators can process items in any order, their relative order
in the map is still preserved for operations like reduce
and collect
.
Source§impl<K, V, S> IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<K, V, S> IndexMap<K, V, S>
Requires crate feature "rayon"
.
Sourcepub fn par_values_mut(&mut self) -> ParValuesMut<'_, K, V>
pub fn par_values_mut(&mut self) -> ParValuesMut<'_, K, V>
Return a parallel iterator over mutable references to the the values of the map
While parallel iterators can process items in any order, their relative order
in the map is still preserved for operations like reduce
and collect
.
Sourcepub fn par_sort_keys(&mut self)where
K: Ord,
pub fn par_sort_keys(&mut self)where
K: Ord,
Sort the map’s key-value pairs in parallel, by the default ordering of the keys.
Sourcepub fn par_sort_by<F>(&mut self, cmp: F)
pub fn par_sort_by<F>(&mut self, cmp: F)
Sort the map’s key-value pairs in place and in parallel, using the comparison
function compare
.
The comparison function receives two key and value pairs to compare (you can sort by keys or values or their combination as needed).
Sourcepub fn par_sorted_by<F>(self, cmp: F) -> IntoParIter<K, V>
pub fn par_sorted_by<F>(self, cmp: F) -> IntoParIter<K, V>
Sort the key-value pairs of the map in parallel and return a by value parallel iterator of the key-value pairs with the result.
Trait Implementations§
Source§impl<'de, K, V, S> Deserialize<'de> for IndexMap<K, V, S>
Requires crate feature "serde-1"
impl<'de, K, V, S> Deserialize<'de> for IndexMap<K, V, S>
Requires crate feature "serde-1"
Source§fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>where
D: Deserializer<'de>,
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>where
D: Deserializer<'de>,
Source§impl<'a, K, V, S> Extend<(&'a K, &'a V)> for IndexMap<K, V, S>
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for IndexMap<K, V, S>
Source§fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iterable: I)
fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iterable: I)
Extend the map with all key-value pairs in the iterable.
See the first extend method for more details.
Source§fn extend_one(&mut self, item: A)
fn extend_one(&mut self, item: A)
extend_one
)Source§fn extend_reserve(&mut self, additional: usize)
fn extend_reserve(&mut self, additional: usize)
extend_one
)Source§impl<K, V, S> Extend<(K, V)> for IndexMap<K, V, S>
impl<K, V, S> Extend<(K, V)> for IndexMap<K, V, S>
Source§fn extend<I: IntoIterator<Item = (K, V)>>(&mut self, iterable: I)
fn extend<I: IntoIterator<Item = (K, V)>>(&mut self, iterable: I)
Extend the map with all key-value pairs in the iterable.
This is equivalent to calling insert
for each of
them in order, which means that for keys that already existed
in the map, their value is updated but it keeps the existing order.
New keys are inserted in the order they appear in the sequence. If equivalents of a key occur more than once, the last corresponding value prevails.
Source§fn extend_one(&mut self, item: A)
fn extend_one(&mut self, item: A)
extend_one
)Source§fn extend_reserve(&mut self, additional: usize)
fn extend_reserve(&mut self, additional: usize)
extend_one
)Source§impl<K, V, S> FromIterator<(K, V)> for IndexMap<K, V, S>
impl<K, V, S> FromIterator<(K, V)> for IndexMap<K, V, S>
Source§impl<K, V, S> FromParallelIterator<(K, V)> for IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<K, V, S> FromParallelIterator<(K, V)> for IndexMap<K, V, S>
Requires crate feature "rayon"
.
Source§fn from_par_iter<I>(iter: I) -> Selfwhere
I: IntoParallelIterator<Item = (K, V)>,
fn from_par_iter<I>(iter: I) -> Selfwhere
I: IntoParallelIterator<Item = (K, V)>,
par_iter
. Read moreSource§impl<'a, K, V, Q, S> IndexMut<&'a Q> for IndexMap<K, V, S>
Mutable indexing allows changing / updating values of key-value
pairs that are already present.
impl<'a, K, V, Q, S> IndexMut<&'a Q> for IndexMap<K, V, S>
Mutable indexing allows changing / updating values of key-value pairs that are already present.
You can not insert new pairs with index syntax, use .insert()
.
Source§impl<'de, K, V, S, E> IntoDeserializer<'de, E> for IndexMap<K, V, S>where
K: IntoDeserializer<'de, E> + Eq + Hash,
V: IntoDeserializer<'de, E>,
S: BuildHasher,
E: Error,
impl<'de, K, V, S, E> IntoDeserializer<'de, E> for IndexMap<K, V, S>where
K: IntoDeserializer<'de, E> + Eq + Hash,
V: IntoDeserializer<'de, E>,
S: BuildHasher,
E: Error,
Source§type Deserializer = MapDeserializer<'de, <IndexMap<K, V, S> as IntoIterator>::IntoIter, E>
type Deserializer = MapDeserializer<'de, <IndexMap<K, V, S> as IntoIterator>::IntoIter, E>
Source§fn into_deserializer(self) -> Self::Deserializer
fn into_deserializer(self) -> Self::Deserializer
Source§impl<'a, K, V, S> IntoIterator for &'a IndexMap<K, V, S>
impl<'a, K, V, S> IntoIterator for &'a IndexMap<K, V, S>
Source§impl<'a, K, V, S> IntoIterator for &'a mut IndexMap<K, V, S>
impl<'a, K, V, S> IntoIterator for &'a mut IndexMap<K, V, S>
Source§impl<K, V, S> IntoIterator for IndexMap<K, V, S>
impl<K, V, S> IntoIterator for IndexMap<K, V, S>
Source§impl<'a, K, V, S> IntoParallelIterator for &'a IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<'a, K, V, S> IntoParallelIterator for &'a IndexMap<K, V, S>
Requires crate feature "rayon"
.
Source§impl<'a, K, V, S> IntoParallelIterator for &'a mut IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<'a, K, V, S> IntoParallelIterator for &'a mut IndexMap<K, V, S>
Requires crate feature "rayon"
.
Source§impl<K, V, S> IntoParallelIterator for IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<K, V, S> IntoParallelIterator for IndexMap<K, V, S>
Requires crate feature "rayon"
.
Source§impl<K, V, S> MutableKeys for IndexMap<K, V, S>
Opt-in mutable access to keys.
impl<K, V, S> MutableKeys for IndexMap<K, V, S>
Opt-in mutable access to keys.
See MutableKeys
for more information.
type Key = K
type Value = V
Source§fn get_full_mut2<Q>(&mut self, key: &Q) -> Option<(usize, &mut K, &mut V)>
fn get_full_mut2<Q>(&mut self, key: &Q) -> Option<(usize, &mut K, &mut V)>
Source§fn retain2<F>(&mut self, keep: F)
fn retain2<F>(&mut self, keep: F)
keep
returns true
. Read moreSource§fn __private_marker(&self) -> PrivateMarker
fn __private_marker(&self) -> PrivateMarker
Source§impl<'a, K, V, S> ParallelExtend<(&'a K, &'a V)> for IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<'a, K, V, S> ParallelExtend<(&'a K, &'a V)> for IndexMap<K, V, S>
Requires crate feature "rayon"
.
Source§fn par_extend<I>(&mut self, iter: I)
fn par_extend<I>(&mut self, iter: I)
par_iter
. Read moreSource§impl<K, V, S> ParallelExtend<(K, V)> for IndexMap<K, V, S>
Requires crate feature "rayon"
.
impl<K, V, S> ParallelExtend<(K, V)> for IndexMap<K, V, S>
Requires crate feature "rayon"
.
Source§fn par_extend<I>(&mut self, iter: I)where
I: IntoParallelIterator<Item = (K, V)>,
fn par_extend<I>(&mut self, iter: I)where
I: IntoParallelIterator<Item = (K, V)>,
par_iter
. Read moreimpl<K, V, S> Eq for IndexMap<K, V, S>
Auto Trait Implementations§
impl<K, V, S> Freeze for IndexMap<K, V, S>where
S: Freeze,
impl<K, V, S> RefUnwindSafe for IndexMap<K, V, S>
impl<K, V, S> Send for IndexMap<K, V, S>
impl<K, V, S> Sync for IndexMap<K, V, S>
impl<K, V, S> Unpin for IndexMap<K, V, S>
impl<K, V, S> UnwindSafe for IndexMap<K, V, S>
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
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
Source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moreSource§impl<'data, I> IntoParallelRefIterator<'data> for I
impl<'data, I> IntoParallelRefIterator<'data> for I
Source§impl<'data, I> IntoParallelRefMutIterator<'data> for I
impl<'data, I> IntoParallelRefMutIterator<'data> for I
Source§type Iter = <&'data mut I as IntoParallelIterator>::Iter
type Iter = <&'data mut I as IntoParallelIterator>::Iter
Source§type Item = <&'data mut I as IntoParallelIterator>::Item
type Item = <&'data mut I as IntoParallelIterator>::Item
&'data mut T
reference.Source§fn par_iter_mut(
&'data mut self,
) -> <I as IntoParallelRefMutIterator<'data>>::Iter
fn par_iter_mut( &'data mut self, ) -> <I as IntoParallelRefMutIterator<'data>>::Iter
self
. Read more