Struct vec_map::VecMap

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pub struct VecMap<V> { /* private fields */ }
Expand description

A map optimized for small integer keys.

§Examples

use vec_map::VecMap;

let mut months = VecMap::new();
months.insert(1, "Jan");
months.insert(2, "Feb");
months.insert(3, "Mar");

if !months.contains_key(12) {
    println!("The end is near!");
}

assert_eq!(months.get(1), Some(&"Jan"));

if let Some(value) = months.get_mut(3) {
    *value = "Venus";
}

assert_eq!(months.get(3), Some(&"Venus"));

// Print out all months
for (key, value) in &months {
    println!("month {} is {}", key, value);
}

months.clear();
assert!(months.is_empty());

Implementations§

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impl<V> VecMap<V>

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pub fn new() -> Self

Creates an empty VecMap.

§Examples
use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::new();
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pub fn with_capacity(capacity: usize) -> Self

Creates an empty VecMap with space for at least capacity elements before resizing.

§Examples
use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::with_capacity(10);
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pub fn capacity(&self) -> usize

Returns the number of elements the VecMap can hold without reallocating.

§Examples
use vec_map::VecMap;
let map: VecMap<String> = VecMap::with_capacity(10);
assert!(map.capacity() >= 10);
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pub fn reserve_len(&mut self, len: usize)

Reserves capacity for the given VecMap to contain len distinct keys. In the case of VecMap this means reallocations will not occur as long as all inserted keys are less than len.

The collection may reserve more space to avoid frequent reallocations.

§Examples
use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::new();
map.reserve_len(10);
assert!(map.capacity() >= 10);
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pub fn reserve_len_exact(&mut self, len: usize)

Reserves the minimum capacity for the given VecMap to contain len distinct keys. In the case of VecMap this means reallocations will not occur as long as all inserted keys are less than len.

Note that the allocator may give the collection more space than it requests. Therefore capacity cannot be relied upon to be precisely minimal. Prefer reserve_len if future insertions are expected.

§Examples
use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::new();
map.reserve_len_exact(10);
assert!(map.capacity() >= 10);
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pub fn shrink_to_fit(&mut self)

Trims the VecMap of any excess capacity.

The collection may reserve more space to avoid frequent reallocations.

§Examples
use vec_map::VecMap;
let mut map: VecMap<&str> = VecMap::with_capacity(10);
map.shrink_to_fit();
assert_eq!(map.capacity(), 0);
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pub fn keys(&self) -> Keys<'_, V>

Returns an iterator visiting all keys in ascending order of the keys. The iterator’s element type is usize.

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pub fn values(&self) -> Values<'_, V>

Returns an iterator visiting all values in ascending order of the keys. The iterator’s element type is &'r V.

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pub fn values_mut(&mut self) -> ValuesMut<'_, V>

Returns an iterator visiting all values in ascending order of the keys. The iterator’s element type is &'r mut V.

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pub fn iter(&self) -> Iter<'_, V>

Returns an iterator visiting all key-value pairs in ascending order of the keys. The iterator’s element type is (usize, &'r V).

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(3, "c");
map.insert(2, "b");

// Print `1: a` then `2: b` then `3: c`
for (key, value) in map.iter() {
    println!("{}: {}", key, value);
}
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pub fn iter_mut(&mut self) -> IterMut<'_, V>

Returns an iterator visiting all key-value pairs in ascending order of the keys, with mutable references to the values. The iterator’s element type is (usize, &'r mut V).

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(2, "b");
map.insert(3, "c");

for (key, value) in map.iter_mut() {
    *value = "x";
}

for (key, value) in &map {
    assert_eq!(value, &"x");
}
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pub fn append(&mut self, other: &mut Self)

Moves all elements from other into the map while overwriting existing keys.

§Examples
use vec_map::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.insert(2, "b");

let mut b = VecMap::new();
b.insert(3, "c");
b.insert(4, "d");

a.append(&mut b);

assert_eq!(a.len(), 4);
assert_eq!(b.len(), 0);
assert_eq!(a[1], "a");
assert_eq!(a[2], "b");
assert_eq!(a[3], "c");
assert_eq!(a[4], "d");
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pub fn split_off(&mut self, at: usize) -> Self

Splits the collection into two at the given key.

Returns a newly allocated Self. self contains elements [0, at), and the returned Self contains elements [at, max_key).

Note that the capacity of self does not change.

§Examples
use vec_map::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.insert(2, "b");
a.insert(3, "c");
a.insert(4, "d");

let b = a.split_off(3);

assert_eq!(a[1], "a");
assert_eq!(a[2], "b");

assert_eq!(b[3], "c");
assert_eq!(b[4], "d");
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pub fn drain(&mut self) -> Drain<'_, V>

Returns an iterator visiting all key-value pairs in ascending order of the keys, emptying (but not consuming) the original VecMap. The iterator’s element type is (usize, &'r V). Keeps the allocated memory for reuse.

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(3, "c");
map.insert(2, "b");

let vec: Vec<(usize, &str)> = map.drain().collect();

assert_eq!(vec, [(1, "a"), (2, "b"), (3, "c")]);
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pub fn len(&self) -> usize

Returns the number of elements in the map.

§Examples
use vec_map::VecMap;

let mut a = VecMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);
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pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

§Examples
use vec_map::VecMap;

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

Clears the map, removing all key-value pairs.

§Examples
use vec_map::VecMap;

let mut a = VecMap::new();
a.insert(1, "a");
a.clear();
assert!(a.is_empty());
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pub fn get(&self, key: usize) -> Option<&V>

Returns a reference to the value corresponding to the key.

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.get(1), Some(&"a"));
assert_eq!(map.get(2), None);
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pub fn contains_key(&self, key: usize) -> bool

Returns true if the map contains a value for the specified key.

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(1), true);
assert_eq!(map.contains_key(2), false);
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pub fn get_mut(&mut self, key: usize) -> Option<&mut V>

Returns a mutable reference to the value corresponding to the key.

§Examples
use vec_map::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");
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pub fn insert(&mut self, key: usize, value: V) -> Option<V>

Inserts a key-value pair into the map. If the key already had a value present in the map, that value is returned. Otherwise, None is returned.

§Examples
use vec_map::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");
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pub fn remove(&mut self, key: usize) -> Option<V>

Removes a key from the map, returning the value at the key if the key was previously in the map.

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
assert_eq!(map.remove(1), Some("a"));
assert_eq!(map.remove(1), None);
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pub fn entry(&mut self, key: usize) -> Entry<'_, V>

Gets the given key’s corresponding entry in the map for in-place manipulation.

§Examples
use vec_map::VecMap;

let mut count: VecMap<u32> = VecMap::new();

// count the number of occurrences of numbers in the vec
for x in vec![1, 2, 1, 2, 3, 4, 1, 2, 4] {
    *count.entry(x).or_insert(0) += 1;
}

assert_eq!(count[1], 3);
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pub fn retain<F>(&mut self, f: F)
where F: FnMut(usize, &mut V) -> bool,

Retains only the elements specified by the predicate.

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

§Examples
use vec_map::VecMap;

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

Trait Implementations§

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impl<V: Clone> Clone for VecMap<V>

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<V: Debug> Debug for VecMap<V>

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

Formats the value using the given formatter. Read more
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impl<V> Default for VecMap<V>

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fn default() -> Self

Returns the “default value” for a type. Read more
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impl<'a, V: Copy> Extend<(usize, &'a V)> for VecMap<V>

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fn extend<I: IntoIterator<Item = (usize, &'a V)>>(&mut self, iter: I)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
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fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<V> Extend<(usize, V)> for VecMap<V>

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fn extend<I: IntoIterator<Item = (usize, V)>>(&mut self, iter: I)

Extends a collection with the contents of an iterator. Read more
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fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)
Extends a collection with exactly one element.
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fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)
Reserves capacity in a collection for the given number of additional elements. Read more
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impl<V> FromIterator<(usize, V)> for VecMap<V>

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fn from_iter<I: IntoIterator<Item = (usize, V)>>(iter: I) -> Self

Creates a value from an iterator. Read more
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impl<V: Hash> Hash for VecMap<V>

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fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'a, V> Index<&'a usize> for VecMap<V>

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type Output = V

The returned type after indexing.
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fn index(&self, i: &usize) -> &V

Performs the indexing (container[index]) operation. Read more
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impl<V> Index<usize> for VecMap<V>

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type Output = V

The returned type after indexing.
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fn index(&self, i: usize) -> &V

Performs the indexing (container[index]) operation. Read more
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impl<'a, V> IndexMut<&'a usize> for VecMap<V>

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fn index_mut(&mut self, i: &usize) -> &mut V

Performs the mutable indexing (container[index]) operation. Read more
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impl<V> IndexMut<usize> for VecMap<V>

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fn index_mut(&mut self, i: usize) -> &mut V

Performs the mutable indexing (container[index]) operation. Read more
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impl<'a, T> IntoIterator for &'a VecMap<T>

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type Item = (usize, &'a T)

The type of the elements being iterated over.
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type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> Iter<'a, T>

Creates an iterator from a value. Read more
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impl<'a, T> IntoIterator for &'a mut VecMap<T>

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type Item = (usize, &'a mut T)

The type of the elements being iterated over.
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type IntoIter = IterMut<'a, T>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> IterMut<'a, T>

Creates an iterator from a value. Read more
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impl<T> IntoIterator for VecMap<T>

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fn into_iter(self) -> IntoIter<T>

Returns an iterator visiting all key-value pairs in ascending order of the keys, consuming the original VecMap. The iterator’s element type is (usize, &'r V).

§Examples
use vec_map::VecMap;

let mut map = VecMap::new();
map.insert(1, "a");
map.insert(3, "c");
map.insert(2, "b");

let vec: Vec<(usize, &str)> = map.into_iter().collect();

assert_eq!(vec, [(1, "a"), (2, "b"), (3, "c")]);
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type Item = (usize, T)

The type of the elements being iterated over.
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type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?
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impl<V: Ord> Ord for VecMap<V>

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fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl<V: PartialEq> PartialEq for VecMap<V>

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fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<V: PartialOrd> PartialOrd for VecMap<V>

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fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<V: Eq> Eq for VecMap<V>

Auto Trait Implementations§

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impl<V> RefUnwindSafe for VecMap<V>
where V: RefUnwindSafe,

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impl<V> Send for VecMap<V>
where V: Send,

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impl<V> Sync for VecMap<V>
where V: Sync,

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impl<V> Unpin for VecMap<V>
where V: Unpin,

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impl<V> UnwindSafe for VecMap<V>
where V: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.