Question

I want to merge all data in two arraylist in c#. Some data in arraylist got same with another arraylist. i don’t want duplicate data when merge.

ArrayList1   ArrayList2
    1             1
    2             2
    3             4
                  5

I’ve try the coding below. but the result not as i expected:

for(int i = 0; i<arrayList2;i++)
{
  for(int j = 0; j<arrayList1;j++)
  {
     if(arraylist1[i] == arraylist2[j])
     {
        newArraylist.add(arraylist[i]+"-same");
     }
     else
     {
        newArraylist.add(arraylist[i]+"-from arrayList2");
     }
  }
}

The result from code above is :

newArrayList
   1 - same
   2 - same
   4 - from arraylist2
   5 - from arraylist2

the result that i want :

 newArrayList
       1 - same
       2 - same
       3 - from arraylist1
       4 - from arraylist2
       5 - from arraylist2

Answer 1

How about this:

var arrayList1 = new ArrayList {1, 2, 3};
var arrayList2 = new ArrayList {1, 2, 4, 5};
var newList = new ArrayList();

foreach (var item in arrayList1)
{
    if(arrayList2.Contains(item))
    {
        newList.Add(string.Format("{0} - same", item));
        arrayList2.Remove(item);
    }
    else
    {
        newList.Add(string.Format("{0} - from arrayList1", item));
    }
}

foreach(var item in arrayList2)
{
    newList.Add(string.Format("{0} - from arrayList2", item));
}

This will give you this result:

1 - same
2 - same
3 - from arraylist1
4 - from arraylist2
5 - from arraylist2