How do can a list can be filtered

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How can a list be filtered,
If suppose i got a model <list> like

lstEmpDetails:

EmpName  FineAmt  PaidAmt
  A       10        -
  A       -         10
  B       50        -
  A       -         25
  C       -         100

I need the output like:

EmpName  FineAmt  PaidAmt
  B       50        -
  A       -         25
  C       -         100

How can I do this using Linq by using the EmpName,FineAmt and PaidAmt

Posted 20-Jan-15 22:34pm

fiashieen

Updated 21-Jan-15 1:00am

v4

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Staffan Bruun 21-Jan-15 4:47am

Do you only need to list those entries where the EmpName occurs exactly once in the set, or is the output based on some arithmetic calculation?

fiashieen 21-Jan-15 4:52am

no no,i just need like, if the EmpName occur's twice and the same amount exist in two different column like FineAmt and PaidAmt then discard from the list else copy.

Thanks7872 21-Jan-15 5:22am

In this case,why A with FineAmt or PaidAmt 10 is removed? What is the exact criterion?

fiashieen 21-Jan-15 5:48am

Actually the Employee 'A' was having a Fine Amount of Rs. 10 afterwards that amount had got paid by him.So that two rows want to be discarded from the list.

2 solutions

Solution 2

Try this:

C#

var Result = lstEmpDetails.SkipWhile(x => lstEmpDetails.Any(y => x.FineAmt == y.PaidAmt && x.PaidAmt == y.FineAmt && x.EmpName== y.EmpName)).ToList();

Regards..

Posted 21-Jan-15 1:39am

Thanks7872

Updated 21-Jan-15 1:40am

v2

Comments

Staffan Bruun 21-Jan-15 9:42am

The problem with that approach is that it will allow one row with the same FineAmt to cancel out several rows with the same PaidAmt, and vice versa.

I understood that the idea was to make sure that each FineAmt row only cancels out one PaidAmt row, which is why my initial solution focuses on counting the number of identical rows of each type.

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Staffan Bruun · Accepted Answer · 2015-01-21T00:32:00

The expression below does the following:

First, it groups the records by name and amount (fine or paid).

Then, for each group:

It selects all the FineAmt rows but skips as many as there are PaidAmt rows also in the same group, so that if there are unpaired FineAmt rows, these will be the only elements in the list. If there are more PaidAmt rows than FineAmt rows, this results in an empty list.

It then does the same thing in reverse for PaidAmt, and concatenates this with the previous list (only one of these lists will have any rows.)

The resulting list, for each group, consists of any unpaired rows in the input.

NOTE: The query assumes that at least one of r.FineAmt or r.PaidAmt in each row has a value other than null.

C#

var filteredRows = lstEmpDetails
                   .GroupBy(r=>new {r.EmpName, Amount=r.FineAmt ?? r.PaidAmt})
                   .SelectMany(g=>
			          g.Where(r=>r.FineAmt.HasValue)
			           .Skip(g.Count(r=>!r.FineAmt.HasValue))
				   .Concat(g.Where(r=>!r.FineAmt.HasValue)
                                            .Skip(g.Count(r=>r.FineAmt.HasValue))));

Update:
To instead get the remaining sums of all the EmpName rows:

This statement groups the rows by name only, then computes the balance for each group.

Finally, it selects only those groups with non-zero balance, then generates the FineAmt, PaidAmt columns accordingly.

NOTE: This assumes you are using int as the data type; if not, change the last Select statement accordingly.

C#

var filteredRows = lstEmpDetails
                   .GroupBy(r=>r.EmpName)
                   .Select(g=>new{
                       EmpName=g.Key, 
                       Balance=g.Sum(r=>(r.FineAmt ?? 0) - (r.PaidAmt ?? 0))
                   })
                   .Where(r=>r.Balance != 0)
                   .Select(r=>new{
                       r.EmpName,
                       FineAmt = r.Balance > 0 ? (int?)r.Balance : null,
                       PaidAmt = r.Balance < 0 ? (int?)-r.Balance : null
                   });