pub type UserReceipts = BTreeMap<OwnedUserId, Receipt>;
events
only.Expand description
A mapping of user ID to receipt.
The user ID is the entity who sent this receipt.
Aliased Type§
struct UserReceipts { /* private fields */ }
Implementations
Source§impl<K, V> BTreeMap<K, V>
impl<K, V> BTreeMap<K, V>
1.0.0 (const: 1.66.0) · Sourcepub const fn new() -> BTreeMap<K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub const fn new() -> BTreeMap<K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Makes a new, empty BTreeMap
.
Does not allocate anything on its own.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
// entries can now be inserted into the empty map
map.insert(1, "a");
Source§impl<K, V, A> BTreeMap<K, V, A>
impl<K, V, A> BTreeMap<K, V, A>
1.0.0 · Sourcepub fn iter(&self) -> Iter<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn iter(&self) -> Iter<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Gets an iterator over the entries of the map, sorted by key.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(3, "c");
map.insert(2, "b");
map.insert(1, "a");
for (key, value) in map.iter() {
println!("{key}: {value}");
}
let (first_key, first_value) = map.iter().next().unwrap();
assert_eq!((*first_key, *first_value), (1, "a"));
1.0.0 · Sourcepub fn iter_mut(&mut self) -> IterMut<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn iter_mut(&mut self) -> IterMut<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Gets a mutable iterator over the entries of the map, sorted by key.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::from([
("a", 1),
("b", 2),
("c", 3),
]);
// add 10 to the value if the key isn't "a"
for (key, value) in map.iter_mut() {
if key != &"a" {
*value += 10;
}
}
1.0.0 · Sourcepub fn keys(&self) -> Keys<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn keys(&self) -> Keys<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Gets an iterator over the keys of the map, in sorted order.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(2, "b");
a.insert(1, "a");
let keys: Vec<_> = a.keys().cloned().collect();
assert_eq!(keys, [1, 2]);
1.0.0 · Sourcepub fn values(&self) -> Values<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn values(&self) -> Values<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Gets an iterator over the values of the map, in order by key.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "hello");
a.insert(2, "goodbye");
let values: Vec<&str> = a.values().cloned().collect();
assert_eq!(values, ["hello", "goodbye"]);
1.10.0 · Sourcepub fn values_mut(&mut self) -> ValuesMut<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn values_mut(&mut self) -> ValuesMut<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Gets a mutable iterator over the values of the map, in order by key.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, String::from("hello"));
a.insert(2, String::from("goodbye"));
for value in a.values_mut() {
value.push_str("!");
}
let values: Vec<String> = a.values().cloned().collect();
assert_eq!(values, [String::from("hello!"),
String::from("goodbye!")]);
1.0.0 (const: unstable) · Sourcepub fn len(&self) -> usize
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn len(&self) -> usize
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns the number of elements in the map.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);
1.0.0 (const: unstable) · Sourcepub fn is_empty(&self) -> bool
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn is_empty(&self) -> bool
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns true
if the map contains no elements.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());
Sourcepub fn lower_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, K, V>
🔬This is a nightly-only experimental API. (btree_cursors
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn lower_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, K, V>
btree_cursors
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns a Cursor
pointing at the gap before the smallest key
greater than the given bound.
Passing Bound::Included(x)
will return a cursor pointing to the
gap before the smallest key greater than or equal to x
.
Passing Bound::Excluded(x)
will return a cursor pointing to the
gap before the smallest key greater than x
.
Passing Bound::Unbounded
will return a cursor pointing to the
gap before the smallest key in the map.
§Examples
#![feature(btree_cursors)]
use std::collections::BTreeMap;
use std::ops::Bound;
let map = BTreeMap::from([
(1, "a"),
(2, "b"),
(3, "c"),
(4, "d"),
]);
let cursor = map.lower_bound(Bound::Included(&2));
assert_eq!(cursor.peek_prev(), Some((&1, &"a")));
assert_eq!(cursor.peek_next(), Some((&2, &"b")));
let cursor = map.lower_bound(Bound::Excluded(&2));
assert_eq!(cursor.peek_prev(), Some((&2, &"b")));
assert_eq!(cursor.peek_next(), Some((&3, &"c")));
let cursor = map.lower_bound(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), None);
assert_eq!(cursor.peek_next(), Some((&1, &"a")));
Sourcepub fn lower_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A>
🔬This is a nightly-only experimental API. (btree_cursors
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn lower_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A>
btree_cursors
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns a CursorMut
pointing at the gap before the smallest key
greater than the given bound.
Passing Bound::Included(x)
will return a cursor pointing to the
gap before the smallest key greater than or equal to x
.
Passing Bound::Excluded(x)
will return a cursor pointing to the
gap before the smallest key greater than x
.
Passing Bound::Unbounded
will return a cursor pointing to the
gap before the smallest key in the map.
§Examples
#![feature(btree_cursors)]
use std::collections::BTreeMap;
use std::ops::Bound;
let mut map = BTreeMap::from([
(1, "a"),
(2, "b"),
(3, "c"),
(4, "d"),
]);
let mut cursor = map.lower_bound_mut(Bound::Included(&2));
assert_eq!(cursor.peek_prev(), Some((&1, &mut "a")));
assert_eq!(cursor.peek_next(), Some((&2, &mut "b")));
let mut cursor = map.lower_bound_mut(Bound::Excluded(&2));
assert_eq!(cursor.peek_prev(), Some((&2, &mut "b")));
assert_eq!(cursor.peek_next(), Some((&3, &mut "c")));
let mut cursor = map.lower_bound_mut(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), None);
assert_eq!(cursor.peek_next(), Some((&1, &mut "a")));
Sourcepub fn upper_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, K, V>
🔬This is a nightly-only experimental API. (btree_cursors
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn upper_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, K, V>
btree_cursors
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns a Cursor
pointing at the gap after the greatest key
smaller than the given bound.
Passing Bound::Included(x)
will return a cursor pointing to the
gap after the greatest key smaller than or equal to x
.
Passing Bound::Excluded(x)
will return a cursor pointing to the
gap after the greatest key smaller than x
.
Passing Bound::Unbounded
will return a cursor pointing to the
gap after the greatest key in the map.
§Examples
#![feature(btree_cursors)]
use std::collections::BTreeMap;
use std::ops::Bound;
let map = BTreeMap::from([
(1, "a"),
(2, "b"),
(3, "c"),
(4, "d"),
]);
let cursor = map.upper_bound(Bound::Included(&3));
assert_eq!(cursor.peek_prev(), Some((&3, &"c")));
assert_eq!(cursor.peek_next(), Some((&4, &"d")));
let cursor = map.upper_bound(Bound::Excluded(&3));
assert_eq!(cursor.peek_prev(), Some((&2, &"b")));
assert_eq!(cursor.peek_next(), Some((&3, &"c")));
let cursor = map.upper_bound(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), Some((&4, &"d")));
assert_eq!(cursor.peek_next(), None);
Sourcepub fn upper_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A>
🔬This is a nightly-only experimental API. (btree_cursors
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn upper_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A>
btree_cursors
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns a CursorMut
pointing at the gap after the greatest key
smaller than the given bound.
Passing Bound::Included(x)
will return a cursor pointing to the
gap after the greatest key smaller than or equal to x
.
Passing Bound::Excluded(x)
will return a cursor pointing to the
gap after the greatest key smaller than x
.
Passing Bound::Unbounded
will return a cursor pointing to the
gap after the greatest key in the map.
§Examples
#![feature(btree_cursors)]
use std::collections::BTreeMap;
use std::ops::Bound;
let mut map = BTreeMap::from([
(1, "a"),
(2, "b"),
(3, "c"),
(4, "d"),
]);
let mut cursor = map.upper_bound_mut(Bound::Included(&3));
assert_eq!(cursor.peek_prev(), Some((&3, &mut "c")));
assert_eq!(cursor.peek_next(), Some((&4, &mut "d")));
let mut cursor = map.upper_bound_mut(Bound::Excluded(&3));
assert_eq!(cursor.peek_prev(), Some((&2, &mut "b")));
assert_eq!(cursor.peek_next(), Some((&3, &mut "c")));
let mut cursor = map.upper_bound_mut(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), Some((&4, &mut "d")));
assert_eq!(cursor.peek_next(), None);
Source§impl<K, V, A> BTreeMap<K, V, A>
impl<K, V, A> BTreeMap<K, V, A>
1.0.0 · Sourcepub fn clear(&mut self)
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn clear(&mut self)
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Clears the map, removing all elements.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "a");
a.clear();
assert!(a.is_empty());
Sourcepub const fn new_in(alloc: A) -> BTreeMap<K, V, A>
🔬This is a nightly-only experimental API. (btreemap_alloc
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub const fn new_in(alloc: A) -> BTreeMap<K, V, A>
btreemap_alloc
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Makes a new empty BTreeMap with a reasonable choice for B.
§Examples
use std::collections::BTreeMap;
use std::alloc::Global;
let mut map = BTreeMap::new_in(Global);
// entries can now be inserted into the empty map
map.insert(1, "a");
Source§impl<K, V, A> BTreeMap<K, V, A>
impl<K, V, A> BTreeMap<K, V, A>
1.0.0 · Sourcepub fn get<Q>(&self, key: &Q) -> Option<&V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn get<Q>(&self, key: &Q) -> Option<&V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);
1.40.0 · Sourcepub fn get_key_value<Q>(&self, k: &Q) -> Option<(&K, &V)>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn get_key_value<Q>(&self, k: &Q) -> Option<(&K, &V)>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns the key-value pair corresponding to the supplied key. This is potentially useful:
- for key types where non-identical keys can be considered equal;
- for getting the
&K
stored key value from a borrowed&Q
lookup key; or - for getting a reference to a key with the same lifetime as the collection.
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.
§Examples
use std::cmp::Ordering;
use std::collections::BTreeMap;
#[derive(Clone, Copy, Debug)]
struct S {
id: u32,
name: &'static str, // ignored by equality and ordering operations
}
impl PartialEq for S {
fn eq(&self, other: &S) -> bool {
self.id == other.id
}
}
impl Eq for S {}
impl PartialOrd for S {
fn partial_cmp(&self, other: &S) -> Option<Ordering> {
self.id.partial_cmp(&other.id)
}
}
impl Ord for S {
fn cmp(&self, other: &S) -> Ordering {
self.id.cmp(&other.id)
}
}
let j_a = S { id: 1, name: "Jessica" };
let j_b = S { id: 1, name: "Jess" };
let p = S { id: 2, name: "Paul" };
assert_eq!(j_a, j_b);
let mut map = BTreeMap::new();
map.insert(j_a, "Paris");
assert_eq!(map.get_key_value(&j_a), Some((&j_a, &"Paris")));
assert_eq!(map.get_key_value(&j_b), Some((&j_a, &"Paris"))); // the notable case
assert_eq!(map.get_key_value(&p), None);
1.66.0 · Sourcepub fn first_key_value(&self) -> Option<(&K, &V)>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn first_key_value(&self) -> Option<(&K, &V)>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns the first key-value pair in the map. The key in this pair is the minimum key in the map.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
assert_eq!(map.first_key_value(), None);
map.insert(1, "b");
map.insert(2, "a");
assert_eq!(map.first_key_value(), Some((&1, &"b")));
1.66.0 · Sourcepub fn first_entry(&mut self) -> Option<OccupiedEntry<'_, K, V, A>>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn first_entry(&mut self) -> Option<OccupiedEntry<'_, K, V, A>>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns the first entry in the map for in-place manipulation. The key of this entry is the minimum key in the map.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
map.insert(2, "b");
if let Some(mut entry) = map.first_entry() {
if *entry.key() > 0 {
entry.insert("first");
}
}
assert_eq!(*map.get(&1).unwrap(), "first");
assert_eq!(*map.get(&2).unwrap(), "b");
1.66.0 · Sourcepub fn pop_first(&mut self) -> Option<(K, V)>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn pop_first(&mut self) -> Option<(K, V)>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Removes and returns the first element in the map. The key of this element is the minimum key that was in the map.
§Examples
Draining elements in ascending order, while keeping a usable map each iteration.
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
map.insert(2, "b");
while let Some((key, _val)) = map.pop_first() {
assert!(map.iter().all(|(k, _v)| *k > key));
}
assert!(map.is_empty());
1.66.0 · Sourcepub fn last_key_value(&self) -> Option<(&K, &V)>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn last_key_value(&self) -> Option<(&K, &V)>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns the last key-value pair in the map. The key in this pair is the maximum key in the map.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "b");
map.insert(2, "a");
assert_eq!(map.last_key_value(), Some((&2, &"a")));
1.66.0 · Sourcepub fn last_entry(&mut self) -> Option<OccupiedEntry<'_, K, V, A>>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn last_entry(&mut self) -> Option<OccupiedEntry<'_, K, V, A>>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Returns the last entry in the map for in-place manipulation. The key of this entry is the maximum key in the map.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
map.insert(2, "b");
if let Some(mut entry) = map.last_entry() {
if *entry.key() > 0 {
entry.insert("last");
}
}
assert_eq!(*map.get(&1).unwrap(), "a");
assert_eq!(*map.get(&2).unwrap(), "last");
1.66.0 · Sourcepub fn pop_last(&mut self) -> Option<(K, V)>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn pop_last(&mut self) -> Option<(K, V)>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Removes and returns the last element in the map. The key of this element is the maximum key that was in the map.
§Examples
Draining elements in descending order, while keeping a usable map each iteration.
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
map.insert(2, "b");
while let Some((key, _val)) = map.pop_last() {
assert!(map.iter().all(|(k, _v)| *k < key));
}
assert!(map.is_empty());
1.0.0 · Sourcepub fn contains_key<Q>(&self, key: &Q) -> bool
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn contains_key<Q>(&self, key: &Q) -> bool
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);
1.0.0 · Sourcepub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
if let Some(x) = map.get_mut(&1) {
*x = "b";
}
assert_eq!(map[&1], "b");
1.0.0 · Sourcepub fn insert(&mut self, key: K, value: V) -> Option<V>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn insert(&mut self, key: K, value: V) -> Option<V>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::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");
Sourcepub fn try_insert(
&mut self,
key: K,
value: V,
) -> Result<&mut V, OccupiedError<'_, K, V, A>>where
K: Ord,
🔬This is a nightly-only experimental API. (map_try_insert
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn try_insert(
&mut self,
key: K,
value: V,
) -> Result<&mut V, OccupiedError<'_, K, V, A>>where
K: Ord,
map_try_insert
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Tries to insert a key-value pair into the map, and returns a mutable reference to the value in the entry.
If the map already had this key present, nothing is updated, and an error containing the occupied entry and the value is returned.
§Examples
#![feature(map_try_insert)]
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
assert_eq!(map.try_insert(37, "a").unwrap(), &"a");
let err = map.try_insert(37, "b").unwrap_err();
assert_eq!(err.entry.key(), &37);
assert_eq!(err.entry.get(), &"a");
assert_eq!(err.value, "b");
1.0.0 · Sourcepub fn remove<Q>(&mut self, key: &Q) -> Option<V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn remove<Q>(&mut self, key: &Q) -> Option<V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.remove(&1), Some("a"));
assert_eq!(map.remove(&1), None);
1.45.0 · Sourcepub fn remove_entry<Q>(&mut self, key: &Q) -> Option<(K, V)>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn remove_entry<Q>(&mut self, key: &Q) -> Option<(K, V)>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.remove_entry(&1), Some((1, "a")));
assert_eq!(map.remove_entry(&1), None);
1.53.0 · Sourcepub fn retain<F>(&mut self, f: F)
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn retain<F>(&mut self, f: F)
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x*10)).collect();
// Keep only the elements with even-numbered keys.
map.retain(|&k, _| k % 2 == 0);
assert!(map.into_iter().eq(vec![(0, 0), (2, 20), (4, 40), (6, 60)]));
1.11.0 · Sourcepub fn append(&mut self, other: &mut BTreeMap<K, V, A>)
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn append(&mut self, other: &mut BTreeMap<K, V, A>)
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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
.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "a");
a.insert(2, "b");
a.insert(3, "c"); // Note: Key (3) also present in b.
let mut b = BTreeMap::new();
b.insert(3, "d"); // Note: Key (3) also present in a.
b.insert(4, "e");
b.insert(5, "f");
a.append(&mut b);
assert_eq!(a.len(), 5);
assert_eq!(b.len(), 0);
assert_eq!(a[&1], "a");
assert_eq!(a[&2], "b");
assert_eq!(a[&3], "d"); // Note: "c" has been overwritten.
assert_eq!(a[&4], "e");
assert_eq!(a[&5], "f");
1.17.0 · Sourcepub fn range<T, R>(&self, range: R) -> Range<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn range<T, R>(&self, range: R) -> Range<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.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.
§Panics
Panics if range start > end
.
Panics if range start == end
and both bounds are Excluded
.
§Examples
use std::collections::BTreeMap;
use std::ops::Bound::Included;
let mut map = BTreeMap::new();
map.insert(3, "a");
map.insert(5, "b");
map.insert(8, "c");
for (&key, &value) in map.range((Included(&4), Included(&8))) {
println!("{key}: {value}");
}
assert_eq!(Some((&5, &"b")), map.range(4..).next());
1.17.0 · Sourcepub fn range_mut<T, R>(&mut self, range: R) -> RangeMut<'_, K, V>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn range_mut<T, R>(&mut self, range: R) -> RangeMut<'_, K, V>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Constructs a mutable 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.
§Panics
Panics if range start > end
.
Panics if range start == end
and both bounds are Excluded
.
§Examples
use std::collections::BTreeMap;
let mut map: BTreeMap<&str, i32> =
[("Alice", 0), ("Bob", 0), ("Carol", 0), ("Cheryl", 0)].into();
for (_, balance) in map.range_mut("B".."Cheryl") {
*balance += 100;
}
for (name, balance) in &map {
println!("{name} => {balance}");
}
1.0.0 · Sourcepub fn entry(&mut self, key: K) -> Entry<'_, K, V, A>where
K: Ord,
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn entry(&mut self, key: K) -> Entry<'_, K, V, A>where
K: Ord,
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Gets the given key’s corresponding entry in the map for in-place manipulation.
§Examples
use std::collections::BTreeMap;
let mut count: BTreeMap<&str, usize> = BTreeMap::new();
// count the number of occurrences of letters in the vec
for x in ["a", "b", "a", "c", "a", "b"] {
count.entry(x).and_modify(|curr| *curr += 1).or_insert(1);
}
assert_eq!(count["a"], 3);
assert_eq!(count["b"], 2);
assert_eq!(count["c"], 1);
1.11.0 · Sourcepub fn split_off<Q>(&mut self, key: &Q) -> BTreeMap<K, V, A>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn split_off<Q>(&mut self, key: &Q) -> BTreeMap<K, V, A>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Splits the collection into two at the given key. Returns everything after the given key, including the key.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "a");
a.insert(2, "b");
a.insert(3, "c");
a.insert(17, "d");
a.insert(41, "e");
let b = a.split_off(&3);
assert_eq!(a.len(), 2);
assert_eq!(b.len(), 3);
assert_eq!(a[&1], "a");
assert_eq!(a[&2], "b");
assert_eq!(b[&3], "c");
assert_eq!(b[&17], "d");
assert_eq!(b[&41], "e");
Sourcepub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F, A>
🔬This is a nightly-only experimental API. (btree_extract_if
)Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F, A>
btree_extract_if
)client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Creates an iterator that visits all elements (key-value pairs) in
ascending key order and uses a closure to determine if an element should
be removed. If the closure returns true
, the element is removed from
the map and yielded. If the closure returns false
, or panics, the
element remains in the map and will not be yielded.
The iterator also lets you mutate the value of each element in the closure, regardless of whether you choose to keep or remove it.
If the returned ExtractIf
is not exhausted, e.g. because it is dropped without iterating
or the iteration short-circuits, then the remaining elements will be retained.
Use retain
with a negated predicate if you do not need the returned iterator.
§Examples
Splitting a map into even and odd keys, reusing the original map:
#![feature(btree_extract_if)]
use std::collections::BTreeMap;
let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
let evens: BTreeMap<_, _> = map.extract_if(|k, _v| k % 2 == 0).collect();
let odds = map;
assert_eq!(evens.keys().copied().collect::<Vec<_>>(), [0, 2, 4, 6]);
assert_eq!(odds.keys().copied().collect::<Vec<_>>(), [1, 3, 5, 7]);
1.54.0 · Sourcepub fn into_keys(self) -> IntoKeys<K, V, A>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn into_keys(self) -> IntoKeys<K, V, A>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Creates a consuming iterator visiting all the keys, in sorted order.
The map cannot be used after calling this.
The iterator element type is K
.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(2, "b");
a.insert(1, "a");
let keys: Vec<i32> = a.into_keys().collect();
assert_eq!(keys, [1, 2]);
1.54.0 · Sourcepub fn into_values(self) -> IntoValues<K, V, A>
Available on (crate features client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.
pub fn into_values(self) -> IntoValues<K, V, A>
client-api-c
or client-api-s
) and (crate features client
or server
) and crate feature api
only.Creates a consuming iterator visiting all the values, in order by key.
The map cannot be used after calling this.
The iterator element type is V
.
§Examples
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "hello");
a.insert(2, "goodbye");
let values: Vec<&str> = a.into_values().collect();
assert_eq!(values, ["hello", "goodbye"]);
Trait Implementations
Source§impl<'de, K, V> Deserialize<'de> for BTreeMap<K, V>
Available on crate features std
or alloc
only.
impl<'de, K, V> Deserialize<'de> for BTreeMap<K, V>
std
or alloc
only.Source§fn deserialize<D>(
deserializer: D,
) -> Result<BTreeMap<K, V>, <D as Deserializer<'de>>::Error>where
D: Deserializer<'de>,
fn deserialize<D>(
deserializer: D,
) -> Result<BTreeMap<K, V>, <D as Deserializer<'de>>::Error>where
D: Deserializer<'de>,
1.2.0 · Source§impl<'a, K, V, A> Extend<(&'a K, &'a V)> for BTreeMap<K, V, A>
impl<'a, K, V, A> Extend<(&'a K, &'a V)> for BTreeMap<K, V, A>
Source§fn extend<I>(&mut self, iter: I)
fn extend<I>(&mut self, iter: I)
Source§fn extend_one(&mut self, _: (&'a K, &'a V))
fn extend_one(&mut self, _: (&'a K, &'a V))
extend_one
)Source§fn extend_reserve(&mut self, additional: usize)
fn extend_reserve(&mut self, additional: usize)
extend_one
)1.0.0 · Source§impl<K, V, A> Extend<(K, V)> for BTreeMap<K, V, A>
impl<K, V, A> Extend<(K, V)> for BTreeMap<K, V, A>
Source§fn extend<T>(&mut self, iter: T)where
T: IntoIterator<Item = (K, V)>,
fn extend<T>(&mut self, iter: T)where
T: IntoIterator<Item = (K, V)>,
Source§fn extend_one(&mut self, _: (K, V))
fn extend_one(&mut self, _: (K, V))
extend_one
)Source§fn extend_reserve(&mut self, additional: usize)
fn extend_reserve(&mut self, additional: usize)
extend_one
)Source§impl<'de, K, V, E> IntoDeserializer<'de, E> for BTreeMap<K, V>
Available on crate features std
or alloc
only.
impl<'de, K, V, E> IntoDeserializer<'de, E> for BTreeMap<K, V>
std
or alloc
only.Source§type Deserializer = MapDeserializer<'de, <BTreeMap<K, V> as IntoIterator>::IntoIter, E>
type Deserializer = MapDeserializer<'de, <BTreeMap<K, V> as IntoIterator>::IntoIter, E>
Source§fn into_deserializer(
self,
) -> <BTreeMap<K, V> as IntoDeserializer<'de, E>>::Deserializer
fn into_deserializer( self, ) -> <BTreeMap<K, V> as IntoDeserializer<'de, E>>::Deserializer
1.0.0 · Source§impl<K, V, A> IntoIterator for BTreeMap<K, V, A>
impl<K, V, A> IntoIterator for BTreeMap<K, V, A>
1.0.0 · Source§impl<K, V, A> Ord for BTreeMap<K, V, A>
impl<K, V, A> Ord for BTreeMap<K, V, A>
1.21.0 · Source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
1.0.0 · Source§impl<K, V, A> PartialOrd for BTreeMap<K, V, A>
impl<K, V, A> PartialOrd for BTreeMap<K, V, A>
Source§impl<K, V> Serialize for BTreeMap<K, V>
Available on crate features std
or alloc
only.
impl<K, V> Serialize for BTreeMap<K, V>
std
or alloc
only.