SortedSet. Often we must create a List of items and then sort it. With a SortedSet, we can keep the elements sorted as we add them, potentially improving performance.
And with this collection, we can ensure no duplicate elements are added. The SortedSet thus is a good way to have a collection of unique, ordered items.
Initial example. This program uses the SortedSet collection: it adds 3 strings to a SortedSet of Strings. It then uses the For-Each loop on the SortedSet.
Also The code uses Contains() to see if an element is in the set. We can quickly test to see whether the set contains something.
Module Module1
Sub Main()
' Create new SortedSet.
Dim sorted = New SortedSet(Of String)()
sorted.Add("carrot")
sorted.Add("apple")
sorted.Add("bird")
' Loop over items in SortedSet.
For Each item As String In sorted
Console.WriteLine("SORTEDSET: {0}", item)
Next
' See if SortedSet contains a string.
If sorted.Contains("bird") Then
Console.WriteLine("CONTAINS bird")
End If
End Sub
End ModuleSORTEDSET: apple
SORTEDSET: bird
SORTEDSET: carrot
CONTAINS bird
Overlaps. Does any element in the SortedSet also occur in another collection? The Overlaps method will test a SortedSet against an IEnumerable—this means a List or array (usually).
Start We create a SortedSet, and a List. The value 20 occurs in both collections, so Overlaps returns true.
Finally We create an empty array (where the maximum index is -1). No elements are in common, so Overlaps returns false.
Module Module1
Sub Main()
Dim sorted = New SortedSet(Of Integer)()
sorted.Add(10)
sorted.Add(20)
Dim list = New List(Of Integer)()
list.Add(20)
list.Add(30)
' One element is the same, so Overlaps returns true.
If sorted.Overlaps(list) Then
Console.WriteLine("OVERLAPS = true")
End If
' Create an empty array.' ... The Overlaps method will then return false.
Dim array(-1) As Integer
If sorted.Overlaps(array) Then
Console.WriteLine("NOT REACHED")
End If
End Sub
End ModuleOVERLAPS = true
Notes, performance. It is possible to use SortedSet to improve performance. It lets us eliminate duplicates, and keep a collection sorted, as we go along.
Detail There is no need to sort the items after we are done adding them to the collection.
And There is no need to check for duplicates as we add them—the SortedSet is automatically restricted to distinct elements.
Summary. We explored the SortedSet generic collection in VB.NET. String elements, Integer elements, or many other types can be used in a SortedSet.
Dot Net Perls is a collection of pages with code examples, which are updated to stay current. Programming is an art, and it can be learned from examples.
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This page was last updated on Oct 11, 2023 (text).