Struct BTreeSet 

pub struct BTreeSet<T, A = Global>
where
    A: Allocator + Clone,
{ /* private fields */ }

Available on crate features crypto and std only.

An ordered set based on a B-Tree.

See BTreeMap’s documentation for a detailed discussion of this collection’s performance benefits and drawbacks.

It is a logic error for an item to be modified in such a way that the item’s ordering relative to any other item, as determined by the Ord trait, changes while it is in the set. This is normally only possible through Cell, RefCell, global state, I/O, or unsafe code. The behavior resulting from such a logic error is not specified, but will be encapsulated to the BTreeSet that observed the logic error and not result in undefined behavior. This could include panics, incorrect results, aborts, memory leaks, and non-termination.

Iterators returned by BTreeSet::iter and BTreeSet::into_iter produce their items in order, and take worst-case logarithmic and amortized constant time per item returned.

Examples

use std::collections::BTreeSet;

// Type inference lets us omit an explicit type signature (which
// would be `BTreeSet<&str>` in this example).
let mut books = BTreeSet::new();

// Add some books.
books.insert("A Dance With Dragons");
books.insert("To Kill a Mockingbird");
books.insert("The Odyssey");
books.insert("The Great Gatsby");

// Check for a specific one.
if !books.contains("The Winds of Winter") {
    println!("We have {} books, but The Winds of Winter ain't one.",
             books.len());
}

// Remove a book.
books.remove("The Odyssey");

// Iterate over everything.
for book in &books {
    println!("{book}");
}

A BTreeSet with a known list of items can be initialized from an array:

use std::collections::BTreeSet;

let set = BTreeSet::from([1, 2, 3]);

Implementations

impl<T> BTreeSet<T>

pub const fn new() -> BTreeSet<T>

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Makes a new, empty BTreeSet.

Does not allocate anything on its own.

Examples

use std::collections::BTreeSet;

let mut set: BTreeSet<i32> = BTreeSet::new();

impl<T, A> BTreeSet<T, A>

where A: Allocator + Clone,

pub const fn new_in(alloc: A) -> BTreeSet<T, A>

🔬This is a nightly-only experimental API. (btreemap_alloc)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Makes a new BTreeSet with a reasonable choice of B.

Examples

use std::collections::BTreeSet;
use std::alloc::Global;

let mut set: BTreeSet<i32> = BTreeSet::new_in(Global);

pub fn range<K, R>(&self, range: R) -> Range<'_, T>

where K: Ord + ?Sized, T: Borrow<K> + Ord, R: RangeBounds<K>,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Constructs a double-ended iterator over a sub-range of elements in the set. 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::BTreeSet;
use std::ops::Bound::Included;

let mut set = BTreeSet::new();
set.insert(3);
set.insert(5);
set.insert(8);
for &elem in set.range((Included(&4), Included(&8))) {
    println!("{elem}");
}
assert_eq!(Some(&5), set.range(4..).next());

pub fn difference<'a>( &'a self, other: &'a BTreeSet<T, A>, ) -> Difference<'a, T, A>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Visits the elements representing the difference, i.e., the elements that are in self but not in other, in ascending order.

Examples

use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let mut b = BTreeSet::new();
b.insert(2);
b.insert(3);

let diff: Vec<_> = a.difference(&b).cloned().collect();
assert_eq!(diff, [1]);

pub fn symmetric_difference<'a>( &'a self, other: &'a BTreeSet<T, A>, ) -> SymmetricDifference<'a, T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Visits the elements representing the symmetric difference, i.e., the elements that are in self or in other but not in both, in ascending order.

Examples

use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let mut b = BTreeSet::new();
b.insert(2);
b.insert(3);

let sym_diff: Vec<_> = a.symmetric_difference(&b).cloned().collect();
assert_eq!(sym_diff, [1, 3]);

pub fn intersection<'a>( &'a self, other: &'a BTreeSet<T, A>, ) -> Intersection<'a, T, A>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Visits the elements representing the intersection, i.e., the elements that are both in self and other, in ascending order.

Examples

use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let mut b = BTreeSet::new();
b.insert(2);
b.insert(3);

let intersection: Vec<_> = a.intersection(&b).cloned().collect();
assert_eq!(intersection, [2]);

pub fn union<'a>(&'a self, other: &'a BTreeSet<T, A>) -> Union<'a, T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Visits the elements representing the union, i.e., all the elements in self or other, without duplicates, in ascending order.

Examples

use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);

let mut b = BTreeSet::new();
b.insert(2);

let union: Vec<_> = a.union(&b).cloned().collect();
assert_eq!(union, [1, 2]);

pub fn clear(&mut self)

where A: Clone,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Clears the set, removing all elements.

Examples

use std::collections::BTreeSet;

let mut v = BTreeSet::new();
v.insert(1);
v.clear();
assert!(v.is_empty());

pub fn contains<Q>(&self, value: &Q) -> bool

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns true if the set contains an element equal to the value.

The value may be any borrowed form of the set’s element type, but the ordering on the borrowed form must match the ordering on the element type.

Examples

use std::collections::BTreeSet;

let set = BTreeSet::from([1, 2, 3]);
assert_eq!(set.contains(&1), true);
assert_eq!(set.contains(&4), false);

pub fn get<Q>(&self, value: &Q) -> Option<&T>

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a reference to the element in the set, if any, that is equal to the value.

The value may be any borrowed form of the set’s element type, but the ordering on the borrowed form must match the ordering on the element type.

Examples

use std::collections::BTreeSet;

let set = BTreeSet::from([1, 2, 3]);
assert_eq!(set.get(&2), Some(&2));
assert_eq!(set.get(&4), None);

pub fn is_disjoint(&self, other: &BTreeSet<T, A>) -> bool

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns true if self has no elements in common with other. This is equivalent to checking for an empty intersection.

Examples

use std::collections::BTreeSet;

let a = BTreeSet::from([1, 2, 3]);
let mut b = BTreeSet::new();

assert_eq!(a.is_disjoint(&b), true);
b.insert(4);
assert_eq!(a.is_disjoint(&b), true);
b.insert(1);
assert_eq!(a.is_disjoint(&b), false);

pub fn is_subset(&self, other: &BTreeSet<T, A>) -> bool

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns true if the set is a subset of another, i.e., other contains at least all the elements in self.

Examples

use std::collections::BTreeSet;

let sup = BTreeSet::from([1, 2, 3]);
let mut set = BTreeSet::new();

assert_eq!(set.is_subset(&sup), true);
set.insert(2);
assert_eq!(set.is_subset(&sup), true);
set.insert(4);
assert_eq!(set.is_subset(&sup), false);

pub fn is_superset(&self, other: &BTreeSet<T, A>) -> bool

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns true if the set is a superset of another, i.e., self contains at least all the elements in other.

Examples

use std::collections::BTreeSet;

let sub = BTreeSet::from([1, 2]);
let mut set = BTreeSet::new();

assert_eq!(set.is_superset(&sub), false);

set.insert(0);
set.insert(1);
assert_eq!(set.is_superset(&sub), false);

set.insert(2);
assert_eq!(set.is_superset(&sub), true);

pub fn first(&self) -> Option<&T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a reference to the first element in the set, if any. This element is always the minimum of all elements in the set.

Examples

Basic usage:

use std::collections::BTreeSet;

let mut set = BTreeSet::new();
assert_eq!(set.first(), None);
set.insert(1);
assert_eq!(set.first(), Some(&1));
set.insert(2);
assert_eq!(set.first(), Some(&1));

pub fn last(&self) -> Option<&T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a reference to the last element in the set, if any. This element is always the maximum of all elements in the set.

Examples

Basic usage:

use std::collections::BTreeSet;

let mut set = BTreeSet::new();
assert_eq!(set.last(), None);
set.insert(1);
assert_eq!(set.last(), Some(&1));
set.insert(2);
assert_eq!(set.last(), Some(&2));

pub fn pop_first(&mut self) -> Option<T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Removes the first element from the set and returns it, if any. The first element is always the minimum element in the set.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::new();

set.insert(1);
while let Some(n) = set.pop_first() {
    assert_eq!(n, 1);
}
assert!(set.is_empty());

pub fn pop_last(&mut self) -> Option<T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Removes the last element from the set and returns it, if any. The last element is always the maximum element in the set.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::new();

set.insert(1);
while let Some(n) = set.pop_last() {
    assert_eq!(n, 1);
}
assert!(set.is_empty());

pub fn insert(&mut self, value: T) -> bool

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Adds a value to the set.

Returns whether the value was newly inserted. That is:

• If the set did not previously contain an equal value, true is returned.
• If the set already contained an equal value, false is returned, and the entry is not updated.

See the module-level documentation for more.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::new();

assert_eq!(set.insert(2), true);
assert_eq!(set.insert(2), false);
assert_eq!(set.len(), 1);

pub fn replace(&mut self, value: T) -> Option<T>

where T: Ord,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Adds a value to the set, replacing the existing element, if any, that is equal to the value. Returns the replaced element.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::new();
set.insert(Vec::<i32>::new());

assert_eq!(set.get(&[][..]).unwrap().capacity(), 0);
set.replace(Vec::with_capacity(10));
assert_eq!(set.get(&[][..]).unwrap().capacity(), 10);

pub fn get_or_insert(&mut self, value: T) -> &T

where T: Ord,

🔬This is a nightly-only experimental API. (btree_set_entry)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Inserts the given value into the set if it is not present, then returns a reference to the value in the set.

Examples

#![feature(btree_set_entry)]

use std::collections::BTreeSet;

let mut set = BTreeSet::from([1, 2, 3]);
assert_eq!(set.len(), 3);
assert_eq!(set.get_or_insert(2), &2);
assert_eq!(set.get_or_insert(100), &100);
assert_eq!(set.len(), 4); // 100 was inserted

pub fn get_or_insert_with<Q, F>(&mut self, value: &Q, f: F) -> &T

where T: Borrow<Q> + Ord, Q: Ord + ?Sized, F: FnOnce(&Q) -> T,

🔬This is a nightly-only experimental API. (btree_set_entry)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Inserts a value computed from f into the set if the given value is not present, then returns a reference to the value in the set.

Examples

#![feature(btree_set_entry)]

use std::collections::BTreeSet;

let mut set: BTreeSet<String> = ["cat", "dog", "horse"]
    .iter().map(|&pet| pet.to_owned()).collect();

assert_eq!(set.len(), 3);
for &pet in &["cat", "dog", "fish"] {
    let value = set.get_or_insert_with(pet, str::to_owned);
    assert_eq!(value, pet);
}
assert_eq!(set.len(), 4); // a new "fish" was inserted

pub fn entry(&mut self, value: T) -> Entry<'_, T, A>

where T: Ord,

🔬This is a nightly-only experimental API. (btree_set_entry)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Gets the given value’s corresponding entry in the set for in-place manipulation.

Examples

#![feature(btree_set_entry)]

use std::collections::BTreeSet;
use std::collections::btree_set::Entry::*;

let mut singles = BTreeSet::new();
let mut dupes = BTreeSet::new();

for ch in "a short treatise on fungi".chars() {
    if let Vacant(dupe_entry) = dupes.entry(ch) {
        // We haven't already seen a duplicate, so
        // check if we've at least seen it once.
        match singles.entry(ch) {
            Vacant(single_entry) => {
                // We found a new character for the first time.
                single_entry.insert()
            }
            Occupied(single_entry) => {
                // We've already seen this once, "move" it to dupes.
                single_entry.remove();
                dupe_entry.insert();
            }
        }
    }
}

assert!(!singles.contains(&'t') && dupes.contains(&'t'));
assert!(singles.contains(&'u') && !dupes.contains(&'u'));
assert!(!singles.contains(&'v') && !dupes.contains(&'v'));

pub fn remove<Q>(&mut self, value: &Q) -> bool

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

If the set contains an element equal to the value, removes it from the set and drops it. Returns whether such an element was present.

The value may be any borrowed form of the set’s element type, but the ordering on the borrowed form must match the ordering on the element type.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::new();

set.insert(2);
assert_eq!(set.remove(&2), true);
assert_eq!(set.remove(&2), false);

pub fn take<Q>(&mut self, value: &Q) -> Option<T>

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Removes and returns the element in the set, if any, that is equal to the value.

The value may be any borrowed form of the set’s element type, but the ordering on the borrowed form must match the ordering on the element type.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::from([1, 2, 3]);
assert_eq!(set.take(&2), Some(2));
assert_eq!(set.take(&2), None);

pub fn retain<F>(&mut self, f: F)

where T: Ord, F: FnMut(&T) -> bool,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Retains only the elements specified by the predicate.

In other words, remove all elements e for which f(&e) returns false. The elements are visited in ascending order.

Examples

use std::collections::BTreeSet;

let mut set = BTreeSet::from([1, 2, 3, 4, 5, 6]);
// Keep only the even numbers.
set.retain(|&k| k % 2 == 0);
assert!(set.iter().eq([2, 4, 6].iter()));

pub fn append(&mut self, other: &mut BTreeSet<T, A>)

where T: Ord, A: Clone,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

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

Examples

use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);
a.insert(3);

let mut b = BTreeSet::new();
b.insert(3);
b.insert(4);
b.insert(5);

a.append(&mut b);

assert_eq!(a.len(), 5);
assert_eq!(b.len(), 0);

assert!(a.contains(&1));
assert!(a.contains(&2));
assert!(a.contains(&3));
assert!(a.contains(&4));
assert!(a.contains(&5));

pub fn split_off<Q>(&mut self, value: &Q) -> BTreeSet<T, A>

where Q: Ord + ?Sized, T: Borrow<Q> + Ord, A: Clone,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Splits the collection into two at the value. Returns a new collection with all elements greater than or equal to the value.

Examples

Basic usage:

use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);
a.insert(3);
a.insert(17);
a.insert(41);

let b = a.split_off(&3);

assert_eq!(a.len(), 2);
assert_eq!(b.len(), 3);

assert!(a.contains(&1));
assert!(a.contains(&2));

assert!(b.contains(&3));
assert!(b.contains(&17));
assert!(b.contains(&41));

pub fn extract_if<F, R>( &mut self, range: R, pred: F, ) -> ExtractIf<'_, T, R, F, A>

where T: Ord, R: RangeBounds<T>, F: FnMut(&T) -> bool,

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Creates an iterator that visits elements in the specified range in ascending order and uses a closure to determine if an element should be removed.

If the closure returns true, the element is removed from the set and yielded. If the closure returns false, or panics, the element remains in the set and will not be yielded.

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 extract_if().for_each(drop) if you do not need the returned iterator, or retain with a negated predicate if you also do not need to restrict the range.

Examples

use std::collections::BTreeSet;

// Splitting a set into even and odd values, reusing the original set:
let mut set: BTreeSet<i32> = (0..8).collect();
let evens: BTreeSet<_> = set.extract_if(.., |v| v % 2 == 0).collect();
let odds = set;
assert_eq!(evens.into_iter().collect::<Vec<_>>(), vec![0, 2, 4, 6]);
assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 7]);

// Splitting a set into low and high halves, reusing the original set:
let mut set: BTreeSet<i32> = (0..8).collect();
let low: BTreeSet<_> = set.extract_if(0..4, |_v| true).collect();
let high = set;
assert_eq!(low.into_iter().collect::<Vec<_>>(), [0, 1, 2, 3]);
assert_eq!(high.into_iter().collect::<Vec<_>>(), [4, 5, 6, 7]);

pub fn iter(&self) -> Iter<'_, T>

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Gets an iterator that visits the elements in the BTreeSet in ascending order.

Examples

use std::collections::BTreeSet;

let set = BTreeSet::from([3, 1, 2]);
let mut set_iter = set.iter();
assert_eq!(set_iter.next(), Some(&1));
assert_eq!(set_iter.next(), Some(&2));
assert_eq!(set_iter.next(), Some(&3));
assert_eq!(set_iter.next(), None);

pub fn len(&self) -> usize

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns the number of elements in the set.

Examples

use std::collections::BTreeSet;

let mut v = BTreeSet::new();
assert_eq!(v.len(), 0);
v.insert(1);
assert_eq!(v.len(), 1);

pub fn is_empty(&self) -> bool

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns true if the set contains no elements.

Examples

use std::collections::BTreeSet;

let mut v = BTreeSet::new();
assert!(v.is_empty());
v.insert(1);
assert!(!v.is_empty());

pub fn lower_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, T>

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

🔬This is a nightly-only experimental API. (btree_cursors)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a Cursor pointing at the gap before the smallest element greater than the given bound.

Passing Bound::Included(x) will return a cursor pointing to the gap before the smallest element greater than or equal to x.

Passing Bound::Excluded(x) will return a cursor pointing to the gap before the smallest element greater than x.

Passing Bound::Unbounded will return a cursor pointing to the gap before the smallest element in the set.

Examples

#![feature(btree_cursors)]

use std::collections::BTreeSet;
use std::ops::Bound;

let set = BTreeSet::from([1, 2, 3, 4]);

let cursor = set.lower_bound(Bound::Included(&2));
assert_eq!(cursor.peek_prev(), Some(&1));
assert_eq!(cursor.peek_next(), Some(&2));

let cursor = set.lower_bound(Bound::Excluded(&2));
assert_eq!(cursor.peek_prev(), Some(&2));
assert_eq!(cursor.peek_next(), Some(&3));

let cursor = set.lower_bound(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), None);
assert_eq!(cursor.peek_next(), Some(&1));

pub fn lower_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, T, A>

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

🔬This is a nightly-only experimental API. (btree_cursors)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a CursorMut pointing at the gap before the smallest element greater than the given bound.

Passing Bound::Included(x) will return a cursor pointing to the gap before the smallest element greater than or equal to x.

Passing Bound::Excluded(x) will return a cursor pointing to the gap before the smallest element greater than x.

Passing Bound::Unbounded will return a cursor pointing to the gap before the smallest element in the set.

Examples

#![feature(btree_cursors)]

use std::collections::BTreeSet;
use std::ops::Bound;

let mut set = BTreeSet::from([1, 2, 3, 4]);

let mut cursor = set.lower_bound_mut(Bound::Included(&2));
assert_eq!(cursor.peek_prev(), Some(&1));
assert_eq!(cursor.peek_next(), Some(&2));

let mut cursor = set.lower_bound_mut(Bound::Excluded(&2));
assert_eq!(cursor.peek_prev(), Some(&2));
assert_eq!(cursor.peek_next(), Some(&3));

let mut cursor = set.lower_bound_mut(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), None);
assert_eq!(cursor.peek_next(), Some(&1));

pub fn upper_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, T>

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

🔬This is a nightly-only experimental API. (btree_cursors)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a Cursor pointing at the gap after the greatest element smaller than the given bound.

Passing Bound::Included(x) will return a cursor pointing to the gap after the greatest element smaller than or equal to x.

Passing Bound::Excluded(x) will return a cursor pointing to the gap after the greatest element smaller than x.

Passing Bound::Unbounded will return a cursor pointing to the gap after the greatest element in the set.

Examples

#![feature(btree_cursors)]

use std::collections::BTreeSet;
use std::ops::Bound;

let set = BTreeSet::from([1, 2, 3, 4]);

let cursor = set.upper_bound(Bound::Included(&3));
assert_eq!(cursor.peek_prev(), Some(&3));
assert_eq!(cursor.peek_next(), Some(&4));

let cursor = set.upper_bound(Bound::Excluded(&3));
assert_eq!(cursor.peek_prev(), Some(&2));
assert_eq!(cursor.peek_next(), Some(&3));

let cursor = set.upper_bound(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), Some(&4));
assert_eq!(cursor.peek_next(), None);

pub fn upper_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, T, A>

where T: Borrow<Q> + Ord, Q: Ord + ?Sized,

🔬This is a nightly-only experimental API. (btree_cursors)

Available on (crate features rustls or boring or acme) and crate feature rustls only.

Returns a CursorMut pointing at the gap after the greatest element smaller than the given bound.

Passing Bound::Included(x) will return a cursor pointing to the gap after the greatest element smaller than or equal to x.

Passing Bound::Excluded(x) will return a cursor pointing to the gap after the greatest element smaller than x.

Passing Bound::Unbounded will return a cursor pointing to the gap after the greatest element in the set.

Examples

#![feature(btree_cursors)]

use std::collections::BTreeSet;
use std::ops::Bound;

let mut set = BTreeSet::from([1, 2, 3, 4]);

let mut cursor = set.upper_bound_mut(Bound::Included(&3));
assert_eq!(cursor.peek_prev(), Some(&3));
assert_eq!(cursor.peek_next(), Some(&4));

let mut cursor = set.upper_bound_mut(Bound::Excluded(&3));
assert_eq!(cursor.peek_prev(), Some(&2));
assert_eq!(cursor.peek_next(), Some(&3));

let mut cursor = set.upper_bound_mut(Bound::Unbounded);
assert_eq!(cursor.peek_prev(), Some(&4));
assert_eq!(cursor.peek_next(), None);

Trait Implementations

impl<T, A> BitAnd<&BTreeSet<T, A>> for &BTreeSet<T, A>

where T: Ord + Clone, A: Allocator + Clone,

fn bitand(self, rhs: &BTreeSet<T, A>) -> BTreeSet<T, A>

Returns the intersection of self and rhs as a new BTreeSet<T>.

Examples

use std::collections::BTreeSet;

let a = BTreeSet::from([1, 2, 3]);
let b = BTreeSet::from([2, 3, 4]);

let result = &a & &b;
assert_eq!(result, BTreeSet::from([2, 3]));

type Output = BTreeSet<T, A>

The resulting type after applying the & operator.

impl<T, A> BitOr<&BTreeSet<T, A>> for &BTreeSet<T, A>

where T: Ord + Clone, A: Allocator + Clone,

fn bitor(self, rhs: &BTreeSet<T, A>) -> BTreeSet<T, A>

Returns the union of self and rhs as a new BTreeSet<T>.

Examples

use std::collections::BTreeSet;

let a = BTreeSet::from([1, 2, 3]);
let b = BTreeSet::from([3, 4, 5]);

let result = &a | &b;
assert_eq!(result, BTreeSet::from([1, 2, 3, 4, 5]));

type Output = BTreeSet<T, A>

The resulting type after applying the | operator.

impl<T, A> BitXor<&BTreeSet<T, A>> for &BTreeSet<T, A>

where T: Ord + Clone, A: Allocator + Clone,

fn bitxor(self, rhs: &BTreeSet<T, A>) -> BTreeSet<T, A>

Returns the symmetric difference of self and rhs as a new BTreeSet<T>.

Examples

use std::collections::BTreeSet;

let a = BTreeSet::from([1, 2, 3]);
let b = BTreeSet::from([2, 3, 4]);

let result = &a ^ &b;
assert_eq!(result, BTreeSet::from([1, 4]));

type Output = BTreeSet<T, A>

The resulting type after applying the ^ operator.

impl<T> CheckDerConstraints for BTreeSet<T>

where T: CheckDerConstraints,

fn check_constraints(any: &Any<'_>) -> Result<(), Error>

impl<T, A> Clone for BTreeSet<T, A>

where T: Clone, A: Allocator + Clone,

fn clone(&self) -> BTreeSet<T, A>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &BTreeSet<T, A>)

Performs copy-assignment from source.

impl<T, A> Debug for BTreeSet<T, A>

where T: Debug, A: Allocator + Clone,

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

Formats the value using the given formatter.

impl<T> Default for BTreeSet<T>

fn default() -> BTreeSet<T>

Creates an empty BTreeSet.

impl<'de, T> Deserialize<'de> for BTreeSet<T>

where T: Deserialize<'de> + Eq + Ord,

Available on crate features std or alloc only.

fn deserialize<D>( deserializer: D, ) -> Result<BTreeSet<T>, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'a, T, A> Extend<&'a T> for BTreeSet<T, A>

where T: 'a + Ord + Copy, A: Allocator + Clone,

fn extend<I>(&mut self, iter: I)

where I: IntoIterator<Item = &'a T>,

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, _: &'a T)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

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.

impl<T, A> Extend<T> for BTreeSet<T, A>

where T: Ord, A: Allocator + Clone,

fn extend<Iter>(&mut self, iter: Iter)

where Iter: IntoIterator<Item = T>,

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, elem: T)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

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.

impl<T, const N: usize> From<[T; N]> for BTreeSet<T>

where T: Ord,

fn from(arr: [T; N]) -> BTreeSet<T>

Converts a [T; N] into a BTreeSet<T>.

If the array contains any equal values, all but one will be dropped.

Examples

use std::collections::BTreeSet;

let set1 = BTreeSet::from([1, 2, 3, 4]);
let set2: BTreeSet<_> = [1, 2, 3, 4].into();
assert_eq!(set1, set2);

impl<'a, T, E> FromDer<'a, E> for BTreeSet<T>

where T: FromDer<'a, E> + Ord, E: From<Error> + Debug,

manual impl of FromDer, so we do not need to require TryFrom<Any> + CheckDerConstraints

fn from_der(bytes: &'a [u8]) -> Result<(&'a [u8], BTreeSet<T>), Err<E>>

Attempt to parse input bytes into a DER object (enforcing constraints)

impl<T> FromIterator<T> for BTreeSet<T>

where T: Ord,

fn from_iter<I>(iter: I) -> BTreeSet<T>

where I: IntoIterator<Item = T>,

Creates a value from an iterator.

impl<T, A> Hash for BTreeSet<T, A>

where T: Hash, A: Allocator + Clone,

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

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'de, T, E> IntoDeserializer<'de, E> for BTreeSet<T>

where T: IntoDeserializer<'de, E> + Eq + Ord, E: Error,

Available on crate features std or alloc only.

type Deserializer = SeqDeserializer<<BTreeSet<T> as IntoIterator>::IntoIter, E>

The type of the deserializer being converted into.

fn into_deserializer( self, ) -> <BTreeSet<T> as IntoDeserializer<'de, E>>::Deserializer

Convert this value into a deserializer.

impl<'a, T, A> IntoIterator for &'a BTreeSet<T, A>

where A: Allocator + Clone,

type Item = &'a T

The type of the elements being iterated over.

type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a, T>

Creates an iterator from a value.

impl<T, A> IntoIterator for BTreeSet<T, A>

where A: Allocator + Clone,

fn into_iter(self) -> IntoIter<T, A>

Gets an iterator for moving out the BTreeSet’s contents in ascending order.

Examples

use std::collections::BTreeSet;

let set = BTreeSet::from([1, 2, 3, 4]);

let v: Vec<_> = set.into_iter().collect();
assert_eq!(v, [1, 2, 3, 4]);

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T, A>

Which kind of iterator are we turning this into?

impl<T, A> Ord for BTreeSet<T, A>

where T: Ord, A: Allocator + Clone,

fn cmp(&self, other: &BTreeSet<T, A>) -> Ordering

This method returns an Ordering between self and other.

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

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T, A> PartialEq for BTreeSet<T, A>

where T: PartialEq, A: Allocator + Clone,

fn eq(&self, other: &BTreeSet<T, A>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T, A> PartialOrd for BTreeSet<T, A>

where T: PartialOrd, A: Allocator + Clone,

fn partial_cmp(&self, other: &BTreeSet<T, A>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T> Serialize for BTreeSet<T>

where T: Serialize,

Available on crate features std or alloc only.

fn serialize<S>( &self, serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<T, A> Sub<&BTreeSet<T, A>> for &BTreeSet<T, A>

where T: Ord + Clone, A: Allocator + Clone,

fn sub(self, rhs: &BTreeSet<T, A>) -> BTreeSet<T, A>

Returns the difference of self and rhs as a new BTreeSet<T>.

Examples

use std::collections::BTreeSet;

let a = BTreeSet::from([1, 2, 3]);
let b = BTreeSet::from([3, 4, 5]);

let result = &a - &b;
assert_eq!(result, BTreeSet::from([1, 2]));

type Output = BTreeSet<T, A>

The resulting type after applying the - operator.

impl<T> Tagged for BTreeSet<T>

const TAG: Tag = Tag::Set

impl<T> ToDer for BTreeSet<T>

where T: ToDer,

fn to_der_len(&self) -> Result<usize, Error>

Get the length of the object (including the header), when encoded

fn write_der_header( &self, writer: &mut dyn Write, ) -> Result<usize, SerializeError>

Attempt to write the DER header to this writer.

fn write_der_content( &self, writer: &mut dyn Write, ) -> Result<usize, SerializeError>

Attempt to write the DER content (all except header) to this writer.

fn to_der_vec(&self) -> Result<Vec<u8>, SerializeError>

Write the DER encoded representation to a newly allocated Vec<u8>.

fn to_der_vec_raw(&self) -> Result<Vec<u8>, SerializeError>

Similar to using to_vec, but uses provided values without changes. This can generate an invalid encoding for a DER object.

fn write_der(&self, writer: &mut dyn Write) -> Result<usize, SerializeError>

Attempt to write the DER encoded representation (header and content) into this writer.

fn write_der_raw(&self, writer: &mut dyn Write) -> Result<usize, SerializeError>

Similar to using to_der, but uses provided values without changes. This can generate an invalid encoding for a DER object.

impl<'a, T> TryFrom<Any<'a>> for BTreeSet<T>

where T: FromBer<'a> + Ord,

type Error = Error

The type returned in the event of a conversion error.

fn try_from(any: Any<'a>) -> Result<BTreeSet<T>, Error>

Performs the conversion.

impl<T, A> Eq for BTreeSet<T, A>

where T: Eq, A: Allocator + Clone,