Select only those values from object where element occurs one time

Question

I need to select only those items from List object where segmentname is one time only e.g. in image which is attached, only return element with SegmentName = "C" as it is only one time in List...

this is sample code which i have tried so far.

var empty = count
  .Where(x => x.Count > 1 & x.SegmentName.Count() == 1)
  .Select(k => new { 
     SegName = k.SegmentName, 
     Value = k.FieldValue, 
     No = k.Count })
  .ToList();

Sample: this is sample

See http://stackoverflow.com/questions/489258/linqs-distinct-on-a-particular-property for an example of linq distinct `elements.DistinctBy(e => e.SegmentName)` — user783836, Dec 15 '16 at 06:13

Mohit S · Answer 1 · 2016-12-15T06:30:53.930

1

This might do the trick for you

elements.GroupBy(x => x).Where(y => y.Count() <= 1).Select(z => z.Key).ToList();

This will return the list of all the elements which exists only once

Example

List<string> SegmentName = new List<string>();
SegmentName.Add("A");
SegmentName.Add("A");
SegmentName.Add("B");
SegmentName.Add("B");
SegmentName.Add("C");
List<string> newlist = SegmentName.GroupBy(x => x).Where(g => g.Count() <= 1).Select(y => y.Key).ToList();

output is

"C"

So for your custom object it should be

count.GroupBy(x => x.SegmentName)
     .Where(y=> y.Count()<=1)
     .Select(k => new {
                        SegName = k.SegmentName, 
                        Value = k.FieldValue, 
                        Count = k.Count 
                      })
     .ToList()

edited Dec 15 '16 at 06:30

answered Dec 15 '16 at 06:22

Mohit S

13,723
6
34
69

`GroupBy` should be based on `x.SegmentName` not `x`; for his example – sujith karivelil Dec 15 '16 at 06:26
Yeah You are correct @un-lucky but the example I have taken is not the object of custom type but its just string list thus we dont need it here .. yes but in the edit I should make the example according to his need – Mohit S Dec 15 '16 at 06:28

score 1 · Accepted Answer · answered Dec 15 '16 at 06:25

1

Hope that you are looking for something like this:

var result = count.GroupBy(x=>x.SegmentName)
                  .Where(y=> y.Count()==1)
                  .Select(k => new {
                                      SegName = k.SegmentName, 
                                      Value = k.FieldValue, 
                                      No = k.Count 
                                    }).ToList()

answered Dec 15 '16 at 06:25

sujith karivelil

28,671
6
55
88

this worked for me var result = count.GroupBy(x => x.SegmentName) .Where(y => y.Count() == 1) .Select(k => k);.. Thanks buddy.. – J.SMTBCJ15 Dec 15 '16 at 06:42
I think the code won't compiled, you cannot access the field `FieldValue` and `Count` after group by the `SegmentName` – Eric Dec 15 '16 at 07:21

score 0 · Answer 3 · answered Dec 15 '16 at 06:29

0

Give GroupBy a go

var empty = count.GroupBy(x => x.SegmentName)
  .Select(x => x.First())
  .ToList();

answered Dec 15 '16 at 06:29

user783836

3,099
2
29
34

score 0 · Answer 4 · answered Dec 15 '16 at 06:47

0

this may help you, check out this one

http://www.dotnettricks.com/learn/linq/sql-joins-with-csharp-linq

answered Dec 15 '16 at 06:47

SUF3

1
1

score 0 · Answer 5 · answered Dec 15 '16 at 07:23

var count = new [] { 
    new { SegmentName = "A", FieldValue = "", Count = 2 }, 
    new { SegmentName = "A", FieldValue = "ABC", Count = 1 },
    new { SegmentName = "B", FieldValue = "", Count = 2 },
    new { SegmentName = "B", FieldValue = "ABC", Count = 1 },
    new { SegmentName = "C", FieldValue = "", Count = 3 },
};

var result = count
    .GroupBy(x => x.SegmentName)
    .Where(y => y.Count() == 1)
    .Select(z => z.First()) // Need to implicitly get the first item here
    .ToList();

foreach(var item in result)
{
    Console.WriteLine("SegmentName={0} FieldValue={1} Count={2}", item.SegmentName, item.FieldValue, item.Count);
}

Select only those values from object where element occurs one time

5 Answers5