Compare two list Items using LINQ

Question

I have an object with the following Properties

public class Name
{
    public string FirstName 
    {
        get;
        set;
    }
    public string LastName
    {
        get;
        set;
    }

}

I get a list of Name Object as NameList which contains two objects as item

I want to compare these two objects in the list to get the object which has same FirstName. I have been looking for a solution for past 2 hours.

In the List of Name object I get two Name objects as

ListItem 1: FirstName : Steve ; LastName : Rogers;

ListItem 2 : FirstName : Steve ; LastName : David;

What i want is to compare these to list Items check if the FirstName Properties are same

Can you provide an example of your data Your question isn't quite clear. Are you saying you have List<Name> which contains just two Name objects? It isn't clear what you mean by "get the object which has same FirstName" because a single object can't have a "same firstname" (same as what?) — Eterm
– Eterm, Commented May 16, 2015 at 13:32
As per my understanding, I think you have a single list and you want to check items with same name inside that list. So you should try grouping... — Anupam Sharma
– Anupam Sharma, Commented May 16, 2015 at 13:36
@Eterm I think he has one list with some Name objects. He want to get all Name objects which has the same FirstName as another Listitem — Simon
– Simon, Commented May 16, 2015 at 13:37
Ok, so a group by then filtering the groups so they have count > 1 should do it. — Eterm
– Eterm, Commented May 16, 2015 at 13:41

Riad Baghbanli · Accepted Answer · 2015-05-16 13:39:01Z

1

If you are looking to get all objects with the same FirstName you should be using GroupBy:

var groups = NameList.GroupBy(li => li.FirstName);

answered May 16, 2015 at 13:39

Riad Baghbanli

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Comments

ffffff01 · Accepted Answer · 2015-05-16 13:42:09Z

1

You want to find all duplicates.

var duplicates = NameList.GroupBy(o => o.FirstName).Where(g => g.Skip(1).Any()).SelectMany(g => g);

edited May 16, 2015 at 13:42

answered May 16, 2015 at 13:37

ffffff01

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7 Comments

Simon Over a year ago

Seems like you understood it wrong :) OP made an edit, check it out

Midhun Over a year ago

Please check the updated question. hope you understood the query

ffffff01 Over a year ago

@Simon Updated answer to get all objects with duplicate firstnames.

ffffff01 Over a year ago

@Midhun Please see updated solution. This gets all duplicates.

Midhun Over a year ago

Sorry for Asking again.. is there any way to check this for immediate preceding listitem?

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