Get unique elements from a List

Question

I would like to remove the duplicate elements from a List. Some elements of the list looks like this:

Book  23
Book  22
Book  19
Notebook 23
Notebook 22
Notebook 19
Pen 23
Pen 22
Pen 19

I would like to keep in the list just

Book 23
Notebook 23
Pen 23

How can i do that ?

What is the second column? Are the numbers part of the strings or are they stored in another list? — Daniel Le, Mar 01 '12 at 09:00
Criteria for choosing those particular strings? First of each? — pavanred, Mar 01 '12 at 09:09
If they are part of the string then they are already unique. — Dave Becker, Mar 01 '12 at 09:14
They are but when you have book 23 and book 22 i would like to keep only book 23 (book 23 and book 22 are unique). — Emil Dumbazu, Mar 01 '12 at 09:15
possible duplicate of [Remove duplicated elements from a List](http://stackoverflow.com/questions/9512385/remove-duplicated-elements-from-a-liststring) — L.B, Mar 01 '12 at 09:34

score 2 · Accepted Answer · answered Mar 01 '12 at 09:54

What about basic looping?

List<string> nodup = dup.Distinct().ToList();
List<int> remIndex = new List<int>();
for (int nIdx = 0; nIdx < nodup.Count; nIdx++)
{
    string[] strArr = nodup[nIdx].Split(' ');
    if (String.Compare(strArr[1], "23", true) != 0)
        remIndex.Add(nIdx);
}
foreach (int remIdx in remIndex)
    nodup.RemoveAt(remIdx);

Hope this is of some help...

score 1 · Answer 2 · edited May 23 '17 at 12:12

1

try this

  List<Person> distinctPeople = allPeople
  .GroupBy(p => p.PersonId)
  .Select(g => g.First())
  .ToList();

from this discussion

use your column names

edited May 23 '17 at 12:12

Community

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answered Mar 01 '12 at 09:02

robasta

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score 0 · Answer 3 · answered Mar 01 '12 at 09:31

0

Try this

list.Sort();

Int32 index = 0; while (index < list.Count - 1) { if (list[index] == list[index +1]) list.RemoveAt(index); else index++; }

answered Mar 01 '12 at 09:31

JayOnDotNet

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Get unique elements from a List

3 Answers3