Struct HashSet

pub struct HashSet<T>
where
    T: Hash + Eq,
{ /* private fields */ }

A hash set implementation based on HashMap.

References:

• Rust Standard Library: std::collections::HashSet

Implementations

impl<T> HashSet<T>

where T: Hash + Eq,

pub fn new() -> Self

Creates an empty set.

pub fn len(&self) -> usize

Gets the number of non-repetitive elements, equivalently to the cardinality of a set.

Complexity

Constant.

pub fn is_empty(&self) -> bool

Returns whether there is no any element in the set.

Complexity

Constant.

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

Inserts an element into the set.

Returns true if there were no such element in the set; returns false if an identical element is already in the set.

Parameters

• value - Element to be inserted.

Complexity

Constant.

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

where T: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns whether an element is present in the set.

This is equivalent to “belongs to ∈” relation in mathematics.

Parameters

• value - Element to be checked whether is in the set.

Complexity

Constant.

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

where T: Borrow<Q>, Q: Hash + Eq + ?Sized,

Removes an element from the set.

Returns true if such item was present and removed; returns false if no such item was found in the set.

Parameters

• value - Element to be removed.

Complexity

Constant.

pub fn iter(&self) -> impl Iterator<Item = &T>

Creates an iterator yielding immutable reference of each item in arbitrary order.

pub fn union<'a>(&'a self, other: &'a HashSet<T>) -> impl Iterator<Item = &T>

Returns an iterator visiting items that exists in self, in other, or in both self and other

This is equivalent to self ∪ other in mathematics.

Parameters

• other - The other set.

pub fn difference<'a>( &'a self, other: &'a HashSet<T>, ) -> impl Iterator<Item = &T>

Returns an iterator visiting items that exists in self but not in other.

This is equivalent to self \ other in mathematics.

Parameters

• other - The other set.

pub fn symmetric_difference<'a>( &'a self, other: &'a HashSet<T>, ) -> impl Iterator<Item = &T>

Returns an iterator visiting items that only exists in either self or other but not in their intersection.

This is equivalent to self △ other in mathematics.

Parameters

• other - The other set.

pub fn intersection<'a>( &'a self, other: &'a HashSet<T>, ) -> impl Iterator<Item = &T>

Returns an iterator visiting items that exists in both self and other.

This is equivalent to self ∩ other in mathematics.

Parameters

• other - The other set.

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

Returns true if self has no elements in common with other.

This is equivalent to checking for an empty intersection, which means their intersection is the empty set ∅.

Parameters

• other - The other set.

Complexity

Linear in the size of self.

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

Returns true if other contains at least all elements in self.

This is equivalent to self ⊆ other in mathematics.

Parameters

• other - The other set.

Complexity

Linear in the size of self.

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

Returns true if self contains at least all elements in other.

This is equivalent to self ⊇ other in mathematics.

Parameters

• other - The other set.

Complexity

Linear in the size of other.

Trait Implementations

impl<'a, 'b, T> BitAnd<&'b HashSet<T>> for &'a HashSet<T>

where T: Hash + Eq + Clone,

The bit_and operator &, as an alias of intersection().

type Output = HashSet<T>

The resulting type after applying the & operator.

fn bitand(self, rhs: &'b HashSet<T>) -> Self::Output

Performs the & operation.

impl<'a, 'b, T> BitOr<&'b HashSet<T>> for &'a HashSet<T>

where T: Hash + Eq + Clone,

The bitor operator |, as an alias of union().

type Output = HashSet<T>

The resulting type after applying the | operator.

fn bitor(self, rhs: &'b HashSet<T>) -> Self::Output

Performs the | operation.

impl<'a, 'b, T> BitXor<&'b HashSet<T>> for &'a HashSet<T>

where T: Hash + Eq + Clone,

The bitxor operator ^, as an alias of symmetric_difference().

type Output = HashSet<T>

The resulting type after applying the ^ operator.

fn bitxor(self, rhs: &'b HashSet<T>) -> Self::Output

Performs the ^ operation.

impl<T> Default for HashSet<T>

where T: Hash + Eq,

fn default() -> Self

Returns the “default value” for a type.

impl<T> FromIterator<T> for HashSet<T>

where T: Hash + Eq,

fn from_iter<I>(iter: I) -> Self

where I: IntoIterator<Item = T>,

Creates a value from an iterator.

impl<T> PartialEq for HashSet<T>

where T: Hash + Eq,

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

Checks the equality of sets.

Two sets are defined to be equal if they contain the same elements and their cardinality are equal.

Set theory definition: x = y ⇒ ∀z, (z ∈ x ⇔ z ∈ y)

Parameters

• other - The other set.

Complexity

Linear in the size of self.

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> PartialOrd for HashSet<T>

where T: Hash + Eq,

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

Compares sets to determine whether one is a subset of the other or not.

Parameters

• other - The other set.

Complexity

Linear in the size of max(self, other).

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<'a, 'b, T> Sub<&'b HashSet<T>> for &'a HashSet<T>

where T: Hash + Eq + Clone,

The sub operator -, as an alias of difference().

type Output = HashSet<T>

The resulting type after applying the - operator.

fn sub(self, rhs: &'b HashSet<T>) -> Self::Output

Performs the - operation.

impl<T> Eq for HashSet<T>

where T: Hash + Eq,

A set is reflecxively equal to itself.