Struct vecmap::map::VecMap

source ·
pub struct VecMap<K, V> { /* private fields */ }
Expand description

A vector-based map implementation which retains the order of inserted entries.

Internally it is represented as a Vec<(K, V)> to support keys that are neither Hash nor Ord.

Implementations§

Create a new map. (Does not allocate.)

Examples
use vecmap::VecMap;

let mut map: VecMap<i32, &str> = VecMap::new();

Create a new map with capacity for capacity key-value pairs. (Does not allocate if capacity is zero.)

Examples
use vecmap::VecMap;

let mut map: VecMap<i32, &str> = VecMap::with_capacity(10);
assert_eq!(map.len(), 0);
assert!(map.capacity() >= 10);

Returns the number of entries the map can hold without reallocating.

Examples
use vecmap::VecMap;

let mut map: VecMap<i32, &str> = VecMap::with_capacity(10);
assert_eq!(map.capacity(), 10);

Returns the number of entries in the map, also referred to as its ‘length’.

Examples
use vecmap::VecMap;

let mut a = VecMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);

Returns true if the map contains no entries.

Examples
use vecmap::VecMap;

let mut a = VecMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());

Clears the map, removing all entries.

Examples
use vecmap::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.clear();
assert!(a.is_empty());

Reverses the order of entries in the map, in place.

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1), ("b", 2), ("c", 3)]);
map.reverse();
let reversed: Vec<(&str, u8)> = map.into_iter().collect();
assert_eq!(reversed, Vec::from_iter([("c", 3), ("b", 2), ("a", 1)]));

Reserves capacity for at least additional more elements to be inserted in the given VecMap<K, V>. The collection may reserve more space to speculatively avoid frequent reallocations. After calling reserve, capacity will be greater than or equal to self.len() + additional. Does nothing if capacity is already sufficient.

Panics

Panics if the new capacity exceeds isize::MAX bytes.

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1)]);
map.reserve(10);
assert!(map.capacity() >= 11);

Retains only the elements specified by the predicate.

In other words, remove all pairs (k, v) for which f(&k, &mut v) returns false.

Examples
use vecmap::VecMap;

let mut map: VecMap<i32, i32> = (0..8).map(|x| (x, x*10)).collect();
map.retain(|&k, _| k % 2 == 0);
assert_eq!(map.len(), 4);

Shrinks the capacity of the map as much as possible. It will drop down as much as possible while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.

Examples
use vecmap::VecMap;

let mut map: VecMap<i32, i32> = VecMap::with_capacity(100);
map.insert(1, 2);
map.insert(3, 4);
assert!(map.capacity() >= 100);
map.shrink_to_fit();
assert!(map.capacity() >= 2);

Shrinks the capacity of the map with a lower limit. It will drop down no lower than the supplied limit while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.

If the current capacity is less than the lower limit, this is a no-op.

Examples
use vecmap::VecMap;

let mut map: VecMap<i32, i32> = VecMap::with_capacity(100);
map.insert(1, 2);
map.insert(3, 4);
assert!(map.capacity() >= 100);
map.shrink_to(10);
assert!(map.capacity() >= 10);
map.shrink_to(0);
assert!(map.capacity() >= 2);

Splits the map into two at the given index.

Returns a newly allocated map containing the key-value pairs in the range [at, len). After the call, the original map will be left containing the key-value pairs [0, at) with its previous capacity unchanged.

Panics

Panics if at > len.

Examples
use vecmap::VecMap;

let mut map = VecMap::from([("a", 1), ("b", 2), ("c", 3)]);
let map2 = map.split_off(1);
assert_eq!(map, VecMap::from([("a", 1)]));
assert_eq!(map2, VecMap::from([("b", 2), ("c", 3)]));

Removes the specified range from the vector in bulk, returning all removed elements as an iterator. If the iterator is dropped before being fully consumed, it drops the remaining removed elements.

The returned iterator keeps a mutable borrow on the vector to optimize its implementation.

Panics

Panics if the starting point is greater than the end point or if the end point is greater than the length of the vector.

Examples
use vecmap::{vecmap, VecMap};

let mut v = vecmap!["a" => 1, "b" => 2, "c" => 3];
let u: VecMap<_, _> = v.drain(1..).collect();
assert_eq!(v, vecmap!["a" => 1]);
assert_eq!(u, vecmap!["b" => 2, "c" => 3]);

// A full range clears the vector, like `clear()` does
v.drain(..);
assert_eq!(v, vecmap![]);

Sorts the map by key.

This sort is stable (i.e., does not reorder equal elements) and O(n * log(n)) worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See sort_unstable_keys.

Examples
use vecmap::VecMap;

let mut map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);

map.sort_keys();
let vec: Vec<_> = map.into_iter().collect();
assert_eq!(vec, [("a", 1), ("b", 2), ("c", 3)]);

Sorts the map by key.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

Examples
use vecmap::VecMap;

let mut map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);

map.sort_unstable_keys();
let vec: Vec<_> = map.into_iter().collect();
assert_eq!(vec, [("a", 1), ("b", 2), ("c", 3)]);

Sorts the map with a comparator function.

This sort is stable (i.e., does not reorder equal elements) and O(n * log(n)) worst-case.

Examples
use vecmap::VecMap;

let mut map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);

map.sort_by(|(k1, _), (k2, _)| k2.cmp(&k1));
let vec: Vec<_> = map.into_iter().collect();
assert_eq!(vec, [("c", 3), ("b", 2), ("a", 1)]);

Sorts the map with a comparator function.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

Examples
use vecmap::VecMap;

let mut map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);

map.sort_unstable_by(|(k1, _), (k2, _)| k2.cmp(&k1));
let vec: Vec<_> = map.into_iter().collect();
assert_eq!(vec, [("c", 3), ("b", 2), ("a", 1)]);

Extracts a slice containing the map entries.

use vecmap::VecMap;

let map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);
let slice = map.as_slice();
assert_eq!(slice, [("b", 2), ("a", 1), ("c", 3)]);

Copies the map entries into a new Vec<(K, V)>.

use vecmap::VecMap;

let map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);
let vec = map.to_vec();
assert_eq!(vec, [("b", 2), ("a", 1), ("c", 3)]);
// Here, `map` and `vec` can be modified independently.

Takes ownership of the map and returns its entries as a Vec<(K, V)>.

use vecmap::VecMap;

let map = VecMap::from([("b", 2), ("a", 1), ("c", 3)]);
let vec = map.into_vec();
assert_eq!(vec, [("b", 2), ("a", 1), ("c", 3)]);

Return true if an equivalent to key exists in the map.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);

Get the first key-value pair.

use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1), ("b", 2)]);
assert_eq!(map.first(), Some((&"a", &1)));

Get the first key-value pair, with mutable access to the value.

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1), ("b", 2)]);

if let Some((_, v)) = map.first_mut() {
    *v = *v + 10;
}
assert_eq!(map.first(), Some((&"a", &11)));

Get the last key-value pair.

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1), ("b", 2)]);
assert_eq!(map.last(), Some((&"b", &2)));
map.pop();
map.pop();
assert_eq!(map.last(), None);

Get the last key-value pair, with mutable access to the value.

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1), ("b", 2)]);

if let Some((_, v)) = map.last_mut() {
    *v = *v + 10;
}
assert_eq!(map.last(), Some((&"b", &12)));

Return a reference to the value stored for key, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);

Return a mutable reference to the value stored for key, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
if let Some(x) = map.get_mut(&1) {
    *x = "b";
}
assert_eq!(map[&1], "b");

Return references to the key-value pair stored at index, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.get_index(0), Some((&1, &"a")));
assert_eq!(map.get_index(1), None);

Return a reference to the key and a mutable reference to the value stored at index, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
if let Some((_, v)) = map.get_index_mut(0) {
    *v = "b";
}
assert_eq!(map[0], "b");

Return the index and references to the key-value pair stored for key, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.get_full(&1), Some((0, &1, &"a")));
assert_eq!(map.get_full(&2), None);

Return the index, a reference to the key and a mutable reference to the value stored for key, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");

if let Some((_, _, v)) = map.get_full_mut(&1) {
    *v = "b";
}
assert_eq!(map.get(&1), Some(&"b"));

Return references to the key-value pair stored for key, if it is present, else None.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
assert_eq!(map.get_key_value(&2), None);

Return item index, if it exists in the map.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
map.insert("a", 10);
map.insert("b", 20);
assert_eq!(map.get_index_of("a"), Some(0));
assert_eq!(map.get_index_of("b"), Some(1));
assert_eq!(map.get_index_of("c"), None);

Removes the last element from the map and returns it, or None if it is empty.

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([("a", 1), ("b", 2)]);
assert_eq!(map.pop(), Some(("b", 2)));
assert_eq!(map.pop(), Some(("a", 1)));
assert!(map.is_empty());
assert_eq!(map.pop(), None);

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!

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([(1, "a"), (2, "b"), (3, "c"), (4, "d")]);
assert_eq!(map.remove(&2), Some("b"));
assert_eq!(map.remove(&2), None);
assert_eq!(map, VecMap::from_iter([(1, "a"), (3, "c"), (4, "d")]));
source

pub fn remove_entry<Q>(&mut self, key: &Q) -> Option<(K, V)>where
    K: Borrow<Q>,
    Q: Eq + ?Sized,

Remove and return the key-value pair equivalent to key.

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!

Examples
use vecmap::VecMap;

let mut map = VecMap::from_iter([(1, "a"), (2, "b"), (3, "c"), (4, "d")]);
assert_eq!(map.remove_entry(&2), Some((2, "b")));
assert_eq!(map.remove_entry(&2), None);
assert_eq!(map, VecMap::from_iter([(1, "a"), (3, "c"), (4, "d")]));

Removes and returns the key-value pair at position index within the map, shifting all elements after it to the left.

If you don’t need the order of elements to be preserved, use swap_remove instead.

Panics

Panics if index is out of bounds.

Examples
use vecmap::VecMap;

let mut v = VecMap::from([("a", 1), ("b", 2), ("c", 3)]);
assert_eq!(v.remove_index(1), ("b", 2));
assert_eq!(v, VecMap::from([("a", 1), ("c", 3)]));

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 position of what used to be the last element!

Return None if key is not in map.

use vecmap::VecMap;

let mut map = VecMap::from_iter([(1, "a"), (2, "b"), (3, "c"), (4, "d")]);
assert_eq!(map.swap_remove(&2), Some("b"));
assert_eq!(map.swap_remove(&2), None);
assert_eq!(map, VecMap::from_iter([(1, "a"), (4, "d"), (3, "c")]));
source

pub fn swap_remove_entry<Q>(&mut self, key: &Q) -> Option<(K, V)>where
    K: Borrow<Q>,
    Q: Eq + ?Sized,

Remove and return the key-value pair equivalent to key.

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 position of what used to be the last element!

Return None if key is not in map.

use vecmap::VecMap;

let mut map = VecMap::from_iter([(1, "a"), (2, "b"), (3, "c"), (4, "d")]);
assert_eq!(map.swap_remove_entry(&2), Some((2, "b")));
assert_eq!(map.swap_remove_entry(&2), None);
assert_eq!(map, VecMap::from_iter([(1, "a"), (4, "d"), (3, "c")]));

Removes a key-value pair from the map and returns it.

The removed key-value pair is replaced by the last key-value pair of the map.

If you need to preserve the element order, use remove instead.

Panics

Panics if index is out of bounds.

Examples
use vecmap::VecMap;

let mut v = VecMap::from([("foo", 1), ("bar", 2), ("baz", 3), ("qux", 4)]);

assert_eq!(v.swap_remove_index(0), ("foo", 1));
assert_eq!(v, VecMap::from([("qux", 4), ("bar", 2), ("baz", 3)]));

assert_eq!(v.swap_remove_index(0), ("qux", 4));
assert_eq!(v, VecMap::from([("baz", 3), ("bar", 2)]));

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.

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.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
assert_eq!(map.insert(37, "a"), None);
assert_eq!(map.is_empty(), false);

map.insert(37, "b");
assert_eq!(map.insert(37, "c"), Some("b"));
assert_eq!(map[&37], "c");

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.

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.

Examples
use vecmap::VecMap;

let mut map = VecMap::new();
assert_eq!(map.insert_full("a", 1), (0, None));
assert_eq!(map.insert_full("b", 2), (1, None));
assert_eq!(map.insert_full("b", 3), (1, Some(2)));
assert_eq!(map["b"], 3);

Get the given key’s corresponding entry in the map for insertion and/or in-place manipulation.

Examples
use vecmap::VecMap;

let mut letters = VecMap::new();

for ch in "a short treatise on fungi".chars() {
    letters.entry(ch).and_modify(|counter| *counter += 1).or_insert(1);
}

assert_eq!(letters[&'s'], 2);
assert_eq!(letters[&'t'], 3);
assert_eq!(letters[&'u'], 1);
assert_eq!(letters.get(&'y'), None);

An iterator visiting all key-value pairs in insertion order. The iterator element type is (&'a K, &'a V).

Examples
use vecmap::VecMap;

let map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for (key, val) in map.iter() {
    println!("key: {key} val: {val}");
}

An iterator visiting all key-value pairs in insertion order, with mutable references to the values. The iterator element type is (&'a K, &'a mut V).

Examples
use vecmap::VecMap;

let mut map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

// Update all values
for (_, val) in map.iter_mut() {
    *val *= 2;
}

for (key, val) in &map {
    println!("key: {key} val: {val}");
}

An iterator visiting all keys in insertion order. The iterator element type is &'a K.

Examples
use vecmap::VecMap;

let map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for key in map.keys() {
    println!("{key}");
}

Creates a consuming iterator visiting all the keys in insertion order. The object cannot be used after calling this. The iterator element type is K.

Examples
use vecmap::VecMap;

let map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

let mut vec: Vec<&str> = map.into_keys().collect();
assert_eq!(vec, ["a", "b", "c"]);

An iterator visiting all values in insertion order. The iterator element type is &'a V.

Examples
use vecmap::VecMap;

let map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for val in map.values() {
    println!("{val}");
}

An iterator visiting all values mutably in insertion order. The iterator element type is &'a mut V.

Examples
use vecmap::VecMap;

let mut map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

for val in map.values_mut() {
    *val = *val + 10;
}

for val in map.values() {
    println!("{val}");
}

Creates a consuming iterator visiting all the values in insertion order. The object cannot be used after calling this. The iterator element type is V.

Examples
use vecmap::VecMap;

let map = VecMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

let mut vec: Vec<i32> = map.into_values().collect();
assert_eq!(vec, [1, 2, 3]);

Trait Implementations§

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Returns the “default value” for a type. Read more
Deserialize this value from the given Serde deserializer. Read more
Extends a collection with the contents of an iterator. Read more
🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
Extends a collection with the contents of an iterator. Read more
🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
Creates a value from an iterator. Read more
The returned type after indexing.
Performs the indexing (container[index]) operation. Read more
The returned type after indexing.
Performs the indexing (container[index]) operation. Read more
Performs the mutable indexing (container[index]) operation. Read more
Performs the mutable indexing (container[index]) operation. Read more
The type of the deserializer being converted into.
Convert this value into a deserializer.
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
Serialize this value into the given Serde serializer. Read more

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.