Add Method

HashSet<T>.Add Method (T)

 

Adds the specified element to a set.

Namespace:   System.Collections.Generic
Assembly:  System.Core (in System.Core.dll)

public bool Add(
	T item
)

Parameters

item
Type: T

The element to add to the set.

Return Value

Type: System.Boolean

true if the element is added to the HashSet<T> object; false if the element is already present.

Implements

ISet<T>.Add(T)

If Count already equals the capacity of the HashSet<T> object, the capacity is automatically adjusted to accommodate the new item.

If Count is less than the capacity of the internal array, this method is an O(1) operation. If the HashSet<T> object must be resized, this method becomes an O(n) operation, where n is Count.

The following example demonstrates how to create and populate two HashSet<T> objects. This example is part of a larger example provided for the UnionWith method.

HashSet<int> evenNumbers = new HashSet<int>();
HashSet<int> oddNumbers = new HashSet<int>();

for (int i = 0; i < 5; i++)
{
    // Populate numbers with just even numbers.
    evenNumbers.Add(i * 2);

    // Populate oddNumbers with just odd numbers.
    oddNumbers.Add((i * 2) + 1);
}

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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