Struct sp_std::collections::btree_set::BTreeSet

pub struct BTreeSet<T> { /* fields omitted */ }

A 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 not result in undefined behavior. This could include panics, incorrect results, aborts, memory leaks, and non-termination.

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);
}

Implementations

impl<T> BTreeSet<T>

pub const fn new() -> BTreeSet<T> where
    T: Ord, 

Makes a new, empty BTreeSet.

Does not allocate anything on its own.

Examples

use std::collections::BTreeSet;

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

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

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.

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 self, other: &'a BTreeSet<T>) -> Difference<'a, T> where
    T: Ord, 

Visits the values representing the difference, i.e., the values 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 self,
    other: &'a BTreeSet<T>
) -> SymmetricDifference<'a, T> where
    T: Ord, 

Visits the values representing the symmetric difference, i.e., the values 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 self, other: &'a BTreeSet<T>) -> Intersection<'a, T> where
    T: Ord, 

Visits the values representing the intersection, i.e., the values 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 self, other: &'a BTreeSet<T>) -> Union<'a, T> where
    T: Ord, 

Visits the values representing the union, i.e., all the values 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)

Clears the set, removing all values.

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, 

Returns true if the set contains a value.

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

Examples

use std::collections::BTreeSet;

let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
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, 

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

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

Examples

use std::collections::BTreeSet;

let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
assert_eq!(set.get(&2), Some(&2));
assert_eq!(set.get(&4), None);

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

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<_> = [1, 2, 3].iter().cloned().collect();
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>) -> bool where
    T: Ord, 

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

Examples

use std::collections::BTreeSet;

let sup: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
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>) -> bool where
    T: Ord, 

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

Examples

use std::collections::BTreeSet;

let sub: BTreeSet<_> = [1, 2].iter().cloned().collect();
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, 

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

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

Examples

Basic usage:

#![feature(map_first_last)]
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, 

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

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

Examples

Basic usage:

#![feature(map_first_last)]
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, 

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

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

Examples

#![feature(map_first_last)]
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, 

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

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

Examples

#![feature(map_first_last)]
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, 

Adds a value to the set.

If the set did not have this value present, true is returned.

If the set did have this value present, 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, 

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

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 remove<Q>(&mut self, value: &Q) -> bool where
    T: Borrow<Q> + Ord,
    Q: Ord + ?Sized, 

Removes a value from the set. Returns whether the value was present in the set.

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

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

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

Examples

use std::collections::BTreeSet;

let mut set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect();
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, 

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

Retains only the elements specified by the predicate.

In other words, remove all elements e such that f(&e) returns false.

Examples

#![feature(btree_retain)]
use std::collections::BTreeSet;

let xs = [1, 2, 3, 4, 5, 6];
let mut set: BTreeSet<i32> = xs.iter().cloned().collect();
// 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>) where
    T: Ord, 

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, key: &Q) -> BTreeSet<T> where
    T: Borrow<Q> + Ord,
    Q: Ord + ?Sized, 

Splits the collection into two at the given key. Returns everything after the given key, including the key.

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 drain_filter<'a, F>(&'a mut self, pred: F) -> DrainFilter<'a, T, F> where
    T: Ord,
    F: 'a + FnMut(&T) -> bool, 

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

Creates an iterator which uses a closure to determine if a value should be removed.

If the closure returns true, then the value is removed and yielded. If the closure returns false, the value will remain in the list and will not be yielded by the iterator.

If the iterator is only partially consumed or not consumed at all, each of the remaining values will still be subjected to the closure and removed and dropped if it returns true.

It is unspecified how many more values will be subjected to the closure if a panic occurs in the closure, or if a panic occurs while dropping a value, or if the DrainFilter itself is leaked.

Examples

Splitting a set into even and odd values, reusing the original set:

#![feature(btree_drain_filter)]
use std::collections::BTreeSet;

let mut set: BTreeSet<i32> = (0..8).collect();
let evens: BTreeSet<_> = set.drain_filter(|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]);

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

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

Examples

use std::collections::BTreeSet;

let set: BTreeSet<usize> = [1, 2, 3].iter().cloned().collect();
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);

Values returned by the iterator are returned in ascending order:

use std::collections::BTreeSet;

let set: BTreeSet<usize> = [3, 1, 2].iter().cloned().collect();
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 const fn len(&self) -> usize

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 const fn is_empty(&self) -> bool

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());

Trait Implementations

impl<'_, '_, T> BitAnd<&'_ BTreeSet<T>> for &'_ BTreeSet<T> where
    T: Clone + Ord, 

type Output = BTreeSet<T>

The resulting type after applying the & operator.

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

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

Examples

use std::collections::BTreeSet;

let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
let b: BTreeSet<_> = vec![2, 3, 4].into_iter().collect();

let result = &a & &b;
let result_vec: Vec<_> = result.into_iter().collect();
assert_eq!(result_vec, [2, 3]);

impl<'_, '_, T> BitOr<&'_ BTreeSet<T>> for &'_ BTreeSet<T> where
    T: Clone + Ord, 

type Output = BTreeSet<T>

The resulting type after applying the | operator.

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

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

Examples

use std::collections::BTreeSet;

let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
let b: BTreeSet<_> = vec![3, 4, 5].into_iter().collect();

let result = &a | &b;
let result_vec: Vec<_> = result.into_iter().collect();
assert_eq!(result_vec, [1, 2, 3, 4, 5]);

impl<'_, '_, T> BitXor<&'_ BTreeSet<T>> for &'_ BTreeSet<T> where
    T: Clone + Ord, 

type Output = BTreeSet<T>

The resulting type after applying the ^ operator.

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

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

Examples

use std::collections::BTreeSet;

let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
let b: BTreeSet<_> = vec![2, 3, 4].into_iter().collect();

let result = &a ^ &b;
let result_vec: Vec<_> = result.into_iter().collect();
assert_eq!(result_vec, [1, 4]);

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

pub fn clone(&self) -> BTreeSet<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for BTreeSet<T> where
    T: Debug, 

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

Formats the value using the given formatter.

impl<T> Default for BTreeSet<T> where
    T: Ord, 

pub fn default() -> BTreeSet<T>

Creates an empty BTreeSet.

impl<T> Eq for BTreeSet<T> where
    T: Eq, 

impl<'a, T> Extend<&'a T> for BTreeSet<T> where
    T: 'a + Ord + Copy, 

pub fn extend<I>(&mut self, iter: I) where
    I: IntoIterator<Item = &'a T>, 

Extends a collection with the contents of an iterator.

pub fn extend_one(&mut self, &'a T)

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

Extends a collection with exactly one element.

pub 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> Extend<T> for BTreeSet<T> where
    T: Ord, 

pub fn extend<Iter>(&mut self, iter: Iter) where
    Iter: IntoIterator<Item = T>, 

Extends a collection with the contents of an iterator.

pub fn extend_one(&mut self, elem: T)

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

Extends a collection with exactly one element.

pub 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> FromIterator<T> for BTreeSet<T> where
    T: Ord, 

pub fn from_iter<I>(iter: I) -> BTreeSet<T> where
    I: IntoIterator<Item = T>, 

Creates a value from an iterator.

impl<T> Hash for BTreeSet<T> where
    T: Hash, 

pub fn hash<__H>(&self, state: &mut __H) where
    __H: Hasher, 

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

impl<T> IntoIterator for BTreeSet<T>

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

pub fn into_iter(self) -> IntoIter<T>

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

Examples

use std::collections::BTreeSet;

let set: BTreeSet<usize> = [1, 2, 3, 4].iter().cloned().collect();

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

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

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?

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

Creates an iterator from a value.

impl<T> Ord for BTreeSet<T> where
    T: Ord, 

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

This method returns an Ordering between self and other.

#[must_use]pub fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]pub fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl<T> PartialEq<BTreeSet<T>> for BTreeSet<T> where
    T: PartialEq<T>, 

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl<T> PartialOrd<BTreeSet<T>> for BTreeSet<T> where
    T: PartialOrd<T>, 

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

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

#[must_use]pub fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

#[must_use]pub fn le(&self, other: &Rhs) -> bool

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

#[must_use]pub fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

#[must_use]pub fn ge(&self, other: &Rhs) -> bool

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

impl<T> StructuralEq for BTreeSet<T>

impl<T> StructuralPartialEq for BTreeSet<T>

impl<'_, '_, T> Sub<&'_ BTreeSet<T>> for &'_ BTreeSet<T> where
    T: Clone + Ord, 

type Output = BTreeSet<T>

The resulting type after applying the - operator.

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

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

Examples

use std::collections::BTreeSet;

let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect();
let b: BTreeSet<_> = vec![3, 4, 5].into_iter().collect();

let result = &a - &b;
let result_vec: Vec<_> = result.into_iter().collect();
assert_eq!(result_vec, [1, 2]);