Let's say that we have a collection of integers as {104723, 104729, 9998,448 }. Objective is to find the largest prime among a collection of numbers. The below program will do so
Imports System.Collections.Generic
Imports System.Linq
Namespace ConsoleApplication1
Class Program
Private Shared Sub Main(args As String())
Dim numberCollection = New List(Of Integer)() From { _
104723, _
104729, _
9998, _
448 _
}
Dim nonPrimeCollection = New List(Of Integer)()
For j As Integer = 0 To numberCollection.Count - 1
For i As Integer = 2 To numberCollection(j) - 1
If numberCollection(j) Mod i = 0 Then
nonPrimeCollection.Add(numberCollection(j))
Exit For
End If
Next
Next
Console.WriteLine("Largest Prime {0} ", numberCollection.Except(nonPrimeCollection).Max())
Console.ReadKey()
End Sub
End Class
End Namespace
Result
--------
Largest Prime 104729
The outer for loop is looping thru the entire collection. The inner for loop starts at 2 and picks up those elements that are not primes. And then we are finding the numbers which are prime and finally finding the max.