C# List with Unique Entries - asp.net-mvc-3

Question

I have a list like this,
List A
ItemNum FileName
001 A.txt,B.txt,A.txt,B.txt
002 A.txt,C.txt,A.txt,C.txt
I need to make a list like this.
ItemNum FileName
001 A.txt,B.txt
002 A.txt,C.txt
Is there any way to do it?

Answer 1

Case sensitive, in a method format:
public List<string> ToDistinct(IEnumerable<string> input)
{
List<string> unique = new List<string>();
foreach (string s in input)
{
List<string> files = s.Split(',').ToList();
unique.Add(String.Join(",", files.Distinct()));
}
return unique;
}
Here's a console method that displays the output like you have above and you can tweak it if you like:
public static void Main(string[] args)
{
List<string> input = new List<string>{"A.txt,B.txt,A.txt,B.txt", "A.txt,C.txt,A.txt,C.txt"};
//Display Input
Console.WriteLine("Input");
Console.WriteLine("ItemNum FileNames");
for(int i = 0; i < input.Count(); i++)
{
Console.WriteLine(String.Format(" {0,-23:000}{1}", i + 1, input[i]));
}
//Build the Unique List
List<string> unique = new List<string>();
foreach (string s in input)
{
List<string> files = s.Split(',').ToList();
unique.Add(String.Join(",", files.Distinct()));
}
//Display Output
Console.WriteLine();
Console.WriteLine("Output");
Console.WriteLine("ItemNum FileNames");
for(int i = 0; i < unique.Count(); i++)
{
Console.WriteLine(String.Format(" {0,-23:000}{1}", i + 1, unique[i]));
}
Console.ReadKey();
}

Answer 2

I'm going to suggest that you convert the FileName's to a List<string>, then all you need is this:
listA.ForEach(x => x.FileNames = x.FileNames.Distinct().ToList());
If there is no specific reason why you're storing what is - for all intents - a list in a string.. why not store it as one? List<string> will allow you to add and remove as you see fit.

Answer 3

List<Item> list = new List<Item>();
list.Add(new Item("001", "A.txt,B.txt,A.txt,B.txt"));
list.Add(new Item("002", "A.txt,C.txt,A.txt,C.txt"));
var newList = from l in list
select new Item() { ItemNum = l.ItemNum,
FileName = string.Join(",", l.FileName.Split(',').Distinct()) };