HashSet<T>

Struct · namespace System

struct HashSet<T>

A set of values (T must be a valid Dictionary key: numbers, bool, char, enums, string, or a struct with GetHashCode/Equals).

var seen = HashSet<string>.Create();
if (seen.Add("a")) ...       // true if the value was new

Static methods

Name	Description
Create	A new, empty set.

Create

static HashSet<T> Create()

A new, empty set.

Methods

Name	Description
IsCreated	Whether the set has storage: made by Create() or [], not the zero value (which cannot change).
Count	The number of values in the set.
Contains	Whether value is in the set.
Add	Adds value to the set.
Remove	Removes value from the set.
Clear	Removes all values.
ToArray	A new array with the values of the set (in no particular order).

IsCreated

bool IsCreated()

Whether the set has storage: made by Create() or [], not the zero value (which cannot change).

Since 0.26

Count

int Count()

The number of values in the set.

Contains

bool Contains(T value)

Whether value is in the set.

Add

bool Add(T value)

Adds value to the set.

Returns true if the value was added, false if it was already in the set.

Panics when the set was not created (HashSet<T>.IsCreated).

Remove

bool Remove(T value)

Removes value from the set.

Returns whether the value was in the set.

Clear

void Clear()

Removes all values.

ToArray

T[] ToArray()

A new array with the values of the set (in no particular order).