C# Linq Finding Similar Rows in Datatable

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Hello all, I have a datatable which includes 3 conclusion rows (C) and 1 decision row (D). I want to find rows with similar conclusion values but different decision value using LINQ. How can I achieve this? Thanks for the help.
For example:

SetName :C1-C2-C3-D
Set1    :1-2-2-3
Set2    :2-1-1-2
Set3    :1-2-2-2

.....
Here the result is Set1 and Set3.

Posted 13-Nov-13 1:18am

Member 12

Updated 14-Nov-13 2:10am

Nelek

v2

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Erik Rude 13-Nov-13 7:27am

Have you thought about GroupBy?

2 solutions

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Dave Kreskowiak · Answer 1 · 2013-11-13T04:52:00

Solution 1

You hvae to define "similar" in terms that the computer will understand. I have no idea how you're going to do that and, to complicate things, it's going to depend on how you store this data in the database. If the database has to manipulate (change) the data on every record to make a determination you're going to kill the query performance.

Posted 13-Nov-13 4:52am

Dave Kreskowiak

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Member 12 13-Nov-13 11:56am

First of all thanks for the replies. I know this is not an easy job. I tried many things including grouping columns but it gives nothing. I think I should write my own data row comparer but I have limited knowledge.

Dave Kreskowiak 13-Nov-13 15:53pm

Grouping isn't going to do anything for you.

You can't even think about writing code until you define in very exact terms what you mean by "similar". What constitutes "similarity" between records? How many records are you comparing? What does the result set look like? If you can't describe the answers to these questions, and more of them, to yourself you have no hope of ever describing it to a computer, which is FAR more picky about it.

Member 12 13-Nov-13 16:50pm

Let me be more specific. My sets contain nominal values about a disease. Condition values are the symptoms and decision value represents whether he/she is ill or not. For example C1 may represent headache symptoms. I though that the best way to deal with nominal values is converting them to numerical values. Therefore I converted them and save to a data table. Now, my goal is to find conflicting records and remove them from the dataset. For example: Suppose that there are two patients. Both have the same symptoms but only one of them is ill (in my example this is Set1 and Set3). These are outlier values and must be removed. That's my goal.

Member 12 · Answer 2 · 2013-11-14T02:07:00

Solution 2

I think this solves my problem.
SELECT C1,C2,C3 FROM
(SELECT C1,C2,C3,D FROM <datatable> GROUP BY C1,C2,C3,D ) AS A
GROUP BY C1,C2,C3
HAVING COUNT(C1)> 1

Posted 14-Nov-13 2:07am

Member 12