How to find Duplicates Elements with LINQ

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By pranay rana On 05 Mar 2011 05:03:59

Tag : LINQ , How to

Skill Level: Beginner

In this snippet I am going to discuss about how to get list of duplicate items for the collection that we do in sql.

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Introduction

In this snippet I am going to discuss about how to get list of duplicate items for the collection that we do in sql.

Implementation

For example I have to get list of the email id which is get entered in user table more than one time.

SELECT email, 
  COUNT(email) AS NumOccurrences
FROM users
GROUP BY email
HAVING ( COUNT(email) > 1 )

Linq query work same as on the set of collection and which make use of count

DataClassesDataContext db = new DataClassesDataContext();
var duplicates = db.Users
    .GroupBy(i => i.emailid)
    .Where(g => g.Count() > 1)
    .Select(g => g.emailid);
foreach (var d in duplicates)
    Console.WriteLine(d);

So by using above query you can easily achieve task of finding duplicate for your set of collection.

About Author

pranay rana

Occupation	-	CEO
Company	-	GMind Solusion
Member Type	-	Expert
Location	-	India
Joined date	-	08 Jan 2011
Home Page	-	http://pranayamr.blogspot.com
Blog Page	-	http://pranayamr.blogspot.com

Hey, I am Pranay Rana, working as a Senior Software engineer in mid-size company located in ahmedabad. Web development in Asp.Net with C# and MS sql server are the experience tools that I have had for the past 4.3 years now. For me def. of programming is : Programming is something that you do once and that get used by multiple for many years You can visit me on my blog - http://pranayamr.blogspot.com/ StackOverFlow - http://stackoverflow.com/users/314488/pranay My CV :- http://careers.stackoverflow.com/pranayamr


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