Struct ordermap::map::OrderMap
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pub struct OrderMap<K, V, S = RandomState> { /* fields omitted */ }
: the crate ordermap has been renamed with no change in functionality to indexmap; please update your dependencies
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 ordermap::OrderMap; // count the frequency of each letter in a sentence. let mut letters = OrderMap::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);
Methods
impl<K, V> OrderMap<K, V>
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fn new() -> Self
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Create a new map. (Does not allocate.)
fn with_capacity(n: usize) -> Self
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Create a new map with capacity for n
key-value pairs. (Does not
allocate if n
is zero.)
Computes in O(n) time.
impl<K, V, S> OrderMap<K, V, S>
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fn with_capacity_and_hasher(n: usize, hash_builder: S) -> Self where
S: BuildHasher,
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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.
fn len(&self) -> usize
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Return the number of key-value pairs in the map.
Computes in O(1) time.
fn is_empty(&self) -> bool
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Returns true if the map contains no elements.
Computes in O(1) time.
fn with_hasher(hash_builder: S) -> Self where
S: BuildHasher,
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S: BuildHasher,
Create a new map with hash_builder
fn hasher(&self) -> &S where
S: BuildHasher,
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S: BuildHasher,
Return a reference to the map's BuildHasher
.
fn capacity(&self) -> usize
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Computes in O(1) time.
impl<K, V, S> OrderMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher,
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K: Hash + Eq,
S: BuildHasher,
fn clear(&mut self)
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Remove all key-value pairs in the map, while preserving its capacity.
Computes in O(n) time.
fn reserve(&mut self, additional: usize)
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Reserve capacity for additional
more key-value pairs.
FIXME Not implemented fully yet.
fn insert(&mut self, key: K, value: V) -> Option<V>
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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.
fn entry(&mut self, key: K) -> Entry<K, V>
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Get the given key’s corresponding entry in the map for insertion and/or in-place manipulation.
Computes in O(1) time (amortized average).
fn iter(&self) -> Iter<K, V>
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Return an iterator over the key-value pairs of the map, in their order
fn iter_mut(&mut self) -> IterMut<K, V>
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Return an iterator over the key-value pairs of the map, in their order
fn keys(&self) -> Keys<K, V>
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Return an iterator over the keys of the map, in their order
fn values(&self) -> Values<K, V>
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Return an iterator over the values of the map, in their order
fn values_mut(&mut self) -> ValuesMut<K, V>
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Return an iterator over mutable references to the the values of the map, in their order
fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
Return true
if an equivalent to key
exists in the map.
Computes in O(1) time (average).
fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
Return a reference to the value stored for key
, if it is present,
else None
.
Computes in O(1) time (average).
fn get_full<Q: ?Sized>(&self, key: &Q) -> Option<(usize, &K, &V)> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
Return item index, key and value
fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
fn get_full_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<(usize, &K, &mut V)> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
NOTE: Same as .swap_remove
Computes in O(1) time (average).
fn swap_remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
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).
fn swap_remove_full<Q: ?Sized>(&mut self, key: &Q) -> Option<(usize, K, V)> where
Q: Hash + Equivalent<K>,
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Q: Hash + Equivalent<K>,
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.
fn pop(&mut self) -> Option<(K, V)>
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Remove the last key-value pair
Computes in O(1) time (average).
fn retain<F>(&mut self, keep: F) where
F: FnMut(&K, &mut V) -> bool,
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F: FnMut(&K, &mut V) -> bool,
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).
fn sort_keys(&mut self) where
K: Ord,
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K: Ord,
Sort the map’s key-value pairs by the default ordering of the keys.
See sort_by
for details.
fn sort_by<F>(&mut self, compare: F) where
F: FnMut(&K, &V, &K, &V) -> Ordering,
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F: FnMut(&K, &V, &K, &V) -> Ordering,
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.
fn sorted_by<F>(self, cmp: F) -> IntoIter<K, V> where
F: FnMut(&K, &V, &K, &V) -> Ordering,
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F: FnMut(&K, &V, &K, &V) -> Ordering,
Sort the key-value pairs of the map and return a by value iterator of the key-value pairs with the result.
The sort is stable.
fn drain(&mut self, range: RangeFull) -> Drain<K, V>
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Clears the OrderMap
, returning all key-value pairs as a drain iterator.
Keeps the allocated memory for reuse.
impl<K, V, S> OrderMap<K, V, S>
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fn get_index(&self, index: usize) -> Option<(&K, &V)>
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Get a key-value pair by index
Valid indices are 0 <= index < self.len()
Computes in O(1) time.
fn get_index_mut(&mut self, index: usize) -> Option<(&mut K, &mut V)>
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Get a key-value pair by index
Valid indices are 0 <= index < self.len()
Computes in O(1) time.
fn swap_remove_index(&mut self, index: usize) -> Option<(K, V)>
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Remove the key-value pair by index
Valid indices are 0 <= index < self.len()
Computes in O(1) time (average).
Trait Implementations
impl<K, V, S> Serialize for OrderMap<K, V, S> where
K: Serialize + Hash + Eq,
V: Serialize,
S: BuildHasher,
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K: Serialize + Hash + Eq,
V: Serialize,
S: BuildHasher,
Requires crate feature "serde-1"
fn serialize<T>(&self, serializer: T) -> Result<T::Ok, T::Error> where
T: Serializer,
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T: Serializer,
Serialize this value into the given Serde serializer. Read more
impl<'de, K, V, S> Deserialize<'de> for OrderMap<K, V, S> where
K: Deserialize<'de> + Eq + Hash,
V: Deserialize<'de>,
S: Default + BuildHasher,
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K: Deserialize<'de> + Eq + Hash,
V: Deserialize<'de>,
S: Default + BuildHasher,
Requires crate feature "serde-1"
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where
D: Deserializer<'de>,
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D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
impl<K, V, S> MutableKeys for OrderMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher,
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K: Eq + Hash,
S: BuildHasher,
Opt-in mutable access to keys.
See MutableKeys
for more information.
type Key = K
type Value = V
fn get_full_mut2<Q: ?Sized>(
&mut self,
key: &Q
) -> Option<(usize, &mut K, &mut V)> where
Q: Hash + Equivalent<K>,
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&mut self,
key: &Q
) -> Option<(usize, &mut K, &mut V)> where
Q: Hash + Equivalent<K>,
Return item index, mutable reference to key and value
fn retain2<F>(&mut self, keep: F) where
F: FnMut(&mut K, &mut V) -> bool,
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F: FnMut(&mut K, &mut V) -> bool,
Scan through each key-value pair in the map and keep those where the closure keep
returns true
. Read more
fn __private_marker(&self) -> PrivateMarker
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This method is not useful in itself – it is there to “seal” the trait for external implementation, so that we can add methods without causing breaking changes. Read more
impl<K: Clone, V: Clone, S: Clone> Clone for OrderMap<K, V, S>
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fn clone(&self) -> OrderMap<K, V, S>
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Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
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Performs copy-assignment from source
. Read more
impl<K, V, S> Debug for OrderMap<K, V, S> where
K: Debug + Hash + Eq,
V: Debug,
S: BuildHasher,
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K: Debug + Hash + Eq,
V: Debug,
S: BuildHasher,
impl<'a, K, V, S> IntoIterator for &'a OrderMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher,
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K: Hash + Eq,
S: BuildHasher,
type Item = (&'a K, &'a V)
The type of the elements being iterated over.
type IntoIter = Iter<'a, K, V>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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Creates an iterator from a value. Read more
impl<'a, K, V, S> IntoIterator for &'a mut OrderMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher,
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K: Hash + Eq,
S: BuildHasher,
type Item = (&'a K, &'a mut V)
The type of the elements being iterated over.
type IntoIter = IterMut<'a, K, V>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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Creates an iterator from a value. Read more
impl<K, V, S> IntoIterator for OrderMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher,
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K: Hash + Eq,
S: BuildHasher,
type Item = (K, V)
The type of the elements being iterated over.
type IntoIter = IntoIter<K, V>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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Creates an iterator from a value. Read more
impl<'a, K, V, Q: ?Sized, S> Index<&'a Q> for OrderMap<K, V, S> where
Q: Hash + Equivalent<K>,
K: Hash + Eq,
S: BuildHasher,
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Q: Hash + Equivalent<K>,
K: Hash + Eq,
S: BuildHasher,
type Output = V
The returned type after indexing.
fn index(&self, key: &'a Q) -> &V
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Panics if key
is not present in the map.
impl<'a, K, V, Q: ?Sized, S> IndexMut<&'a Q> for OrderMap<K, V, S> where
Q: Hash + Equivalent<K>,
K: Hash + Eq,
S: BuildHasher,
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Q: Hash + Equivalent<K>,
K: Hash + Eq,
S: BuildHasher,
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()
.
impl<K, V, S> FromIterator<(K, V)> for OrderMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher + Default,
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K: Hash + Eq,
S: BuildHasher + Default,
fn from_iter<I: IntoIterator<Item = (K, V)>>(iterable: I) -> Self
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Create an OrderMap
from the sequence of key-value pairs in the
iterable.
from_iter
uses the same logic as extend
. See
extend
for more details.
impl<K, V, S> Extend<(K, V)> for OrderMap<K, V, S> where
K: Hash + Eq,
S: BuildHasher,
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K: Hash + Eq,
S: BuildHasher,
fn extend<I: IntoIterator<Item = (K, V)>>(&mut self, iterable: I)
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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 inserted in the order in the sequence. If equivalents of a key occur more than once, the last corresponding value prevails.
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for OrderMap<K, V, S> where
K: Hash + Eq + Copy,
V: Copy,
S: BuildHasher,
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K: Hash + Eq + Copy,
V: Copy,
S: BuildHasher,
fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iterable: I)
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Extend the map with all key-value pairs in the iterable.
See the first extend method for more details.
impl<K, V, S> Default for OrderMap<K, V, S> where
S: BuildHasher + Default,
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S: BuildHasher + Default,
impl<K, V1, S1, V2, S2> PartialEq<OrderMap<K, V2, S2>> for OrderMap<K, V1, S1> where
K: Hash + Eq,
V1: PartialEq<V2>,
S1: BuildHasher,
S2: BuildHasher,
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K: Hash + Eq,
V1: PartialEq<V2>,
S1: BuildHasher,
S2: BuildHasher,
fn eq(&self, other: &OrderMap<K, V2, S2>) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=
.
impl<K, V, S> Eq for OrderMap<K, V, S> where
K: Eq + Hash,
V: Eq,
S: BuildHasher,
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K: Eq + Hash,
V: Eq,
S: BuildHasher,