Distinct items in List

Question

I have an excel spreadsheet that I am trying to populate a list with only unique values. I have found LinqToExcel which I would prefer not to use. At most there will be 2000 rows which isn't very much.

My thought was:

List<string> lst = new List<string>();
string item;

for (i=2; i<2001; i++)
{
    item = ws.cells[i,3];
    if(lst.**notInList**(item))
    {
        lst.Add(item);
    }
}

I know that there isn't notInList(), but I was hoping for something similar or another idea.

Have you tried if ( ! lst.Contains(item) )? – Shar1er80 Jun 04 '15 at 13:25 — Shar1er80, Jun 04 '15 at 13:25
What's wrong with `!lst.Contains(string)`? – Grant Thomas Jun 04 '15 at 13:25 — Grant Thomas, Jun 04 '15 at 13:25

score 2 · Answer 1 · answered Jun 04 '15 at 13:28

2

var values = Enumerable.Range(2, 1999)
                       .Select(i => ws.cells[i,3])
                       .Distinct()
                       .ToList();

answered Jun 04 '15 at 13:28

nvoigt

75,013
26
93
142

score 0 · Answer 2 · answered Jun 04 '15 at 13:26

0

List<string> lst = new List<string>();
string item;

for (i=2; i<2001; i++)
{
    item = ws.cells[i,3];
    if(!lst.Contains(item))
    {
        lst.Add(item);
    }
}

answered Jun 04 '15 at 13:26

mac

485
1
6
29

Additional explanation would improve your answer. – ryanyuyu Jun 04 '15 at 14:02

score 0 · Accepted Answer · answered Jun 04 '15 at 13:26

0

Use Contains instead

List<string> lst = new List<string>();
string item;

for (i=2; i<2001; i++)
{
    item = ws.cells[i,3];
    if(!lst.Contains(item))
    {
        lst.Add(item);
    }
}

answered Jun 04 '15 at 13:26

Brian Dishaw

5,767
34
49

score 0 · Answer 4 · answered Jun 04 '15 at 13:26

If you want the items filtered for identical entries, you could use the .Distinct method from linq.

var distinctList = lst.Distinct();

There's also List.Contains(item)

If you know from the get-go that this collection should contain only unique elements, also consider using a HashSet<T> instead.

Distinct items in List

4 Answers4