Struct PopulatedBTreeMap

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pub struct PopulatedBTreeMap<K, V>(/* private fields */);

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An ordered map based on a B-Tree that is guaranteed to have at least one key-value pair.

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impl<K: Ord, V> PopulatedBTreeMap<K, V>

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pub fn new(key: K, value: V) -> PopulatedBTreeMap<K, V>

Makes a new PopulatedBTreeMap with a single key-value pair.

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pub fn get<Q: Ord + ?Sized>(&self, k: &Q) -> Option<&V>
where K: Borrow<Q>,

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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pub fn get_key_value<Q: Ord + ?Sized>(&self, k: &Q) -> Option<(&K, &V)>
where K: Borrow<Q>,

Returns the key-value pair corresponding to the supplied key.

The supplied key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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pub fn first_key_value(&self) -> (&K, &V)

Returns the first key-value pair in the map. The key in this pair is the minimum key in the map.

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pub fn pop_first(self) -> ((K, V), BTreeMap<K, V>)

Removes and returns the first element in the map. The key of this element is the minimum key that was in the map.

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pub fn last_key_value(&self) -> (&K, &V)

Returns the last key-value pair in the map. The key in this pair is the maximum key in the map.

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pub fn pop_last(self) -> (BTreeMap<K, V>, (K, V))

Removes and returns the last element in the map. The key of this element is the maximum key that was in the map.

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pub fn contains_key<Q: Ord + ?Sized>(&self, k: &Q) -> bool
where K: Borrow<Q>,

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

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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pub fn get_mut<Q: Ord + ?Sized>(&mut self, k: &Q) -> Option<&mut V>
where K: Borrow<Q>,

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

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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pub fn insert(&mut self, key: K, value: V) -> Option<V>

Inserts a key-value pair into the map.

If the map did not have this key present, None is returned.

If the map did have this key present, the value is updated, and the old value is returned. The key is not updated, though; this matters for types that can be == without being identical. See the module-level documentation for more.

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pub fn remove<Q: Ord + ?Sized>( self, k: &Q, ) -> Result<(V, BTreeMap<K, V>), PopulatedBTreeMap<K, V>>
where K: Borrow<Q>,

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

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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pub fn remove_entry<Q: Ord + ?Sized>(self, k: &Q) -> EntryRemovalResult<K, V>
where K: Borrow<Q>,

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

The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.

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pub fn retain(self, predicate: impl FnMut(&K, &mut V) -> bool) -> BTreeMap<K, V>

Retains only the elements specified by the predicate.

In other words, remove all pairs (k, v) for which f(&k, &mut v) returns false. The elements are visited in ascending key order.

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pub fn append(&mut self, other: &mut BTreeMap<K, V>)

Moves all elements from other into self, leaving other empty.

If a key from other is already present in self, the respective value from self will be overwritten with the respective value from other.

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pub fn range<T: Ord + ?Sized>( &self, range: impl RangeBounds<T>, ) -> Range<'_, K, V>
where K: Borrow<T>,

Constructs a double-ended iterator over a sub-range of elements in the map. The simplest way is to use the range syntax min..max, thus range(min..max) will yield elements from min (inclusive) to max (exclusive). The range may also be entered as (Bound<T>, Bound<T>), so for example range((Excluded(4), Included(10))) will yield a left-exclusive, right-inclusive range from 4 to 10.

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