How to union data in ArrayList C# 2.0 ?

Question

How to union data in ArrayList C# in dotnet framework 2?

example of data : 1, 2, 2, 3, 4, 5, 5, 6, 6
how to get 1, 2, 3, 4, 5, 6

Answer 1

Hashtable htCopy = new Hashtable();

foreach (int item in arrListFull) 
{   
    htCopy[item] = null;
}

ArrayList distinctArrayList = new ArrayList(htCopy.Keys);

Answer 2

// Assuming your data is an ArrayList called "source"
ArrayList dest = new ArrayList();
foreach(int i in source) if(!dest.Contains(i)) dest.Add(i);

You should be using List<int> instead of ArrayList, though.

Edit: Alternate solution using Sort+BinarySearch, as suggested by Kobi:

// Assuming your data is an ArrayList called "source"
source.Sort();
ArrayList dest = new ArrayList();
foreach (int i in source) if (dest.BinarySearch(i)<0) dest.Add(i);

Answer 3

public ArrayList RemoveDups ( ArrayList input )
{
    ArrayList single_values = new ArrayList();

    foreach( object item in input)
    {
        if( !single_values.Contains(item) )
        {
            single_values.Add(item);
        }
    }
    return single_values;
}

Answer 4

Have you considered changing your ArrayList to IEnumerable<int>, or perhaps List<int> ?

ArrayList myAL = new ArrayList {8, 1, 1, 1, 2, 1 ,2, 3, 4, 5, 5, 5, 6 };

var myInts = (from i in myAL.Cast<int>()  
              orderby i  
              select  i).Distinct();


foreach (int i in myInts)
{
    Console.WriteLine(i);
}