CODEWITHSUNDEEP
c#
Josh
Josh

Reputation: 1901

Search and remove Duplicates in a List

In this post Other Post I used the programmers suggestion of List<KeyValuePair<string, string>> IdentityLines = new List<KeyValuePair<string, string>>(); to collect multiple string values within certain files of a directory. I now want to remove the duplicate values from that list. Any idea how I can do that in C#? Thanks

Upvotes: 1

Views: 1539

Answers (3)

El Kabong
El Kabong

Reputation: 717

I know this an old question, but here's how I do this:

var inputKeys = new List<KeyValuePair<string, string>>
                          {
                              new KeyValuePair<string, string>("myFirstKey", "one"),
                              new KeyValuePair<string, string>("myFirstKey", "two"),
                              new KeyValuePair<string, string>("mySecondKey", "one"),
                              new KeyValuePair<string, string>("mySecondKey", "two"),
                              new KeyValuePair<string, string>("mySecondKey", "two"),
                          };
 var uniqueKeys = new List<KeyValuePair<string, string>>();

 //get rid of any duplicates
 uniqueKeys.AddRange(inputKeys.Where(keyPair => !uniqueKeys.Contains(keyPair)));

 Assert.AreEqual(inputKeys.Count(), 5);
 Assert.AreEqual(uniqueKeys.Count(), 4);

Upvotes: 0

Robert Harvey
Robert Harvey

Reputation: 180787

static List<T> RemoveDuplicates<T>(List<T> inputList) 
{ 
    Dictionary<T, int> uniqueStore = new Dictionary<T, int>(); 
    List<T> finalList = new List<T>(); 

    foreach (string currValue in inputList) 
    { 
        if (!uniqueStore.ContainsKey(currValue)) 
        { 
            uniqueStore.Add(currValue, 0); 
            finalList.Add(currValue); 
        } 
    } 
    return finalList; 
}

http://www.kirupa.com/net/removingDuplicates.htm

If you want to return an IEnumerable instead, change your return type to IEnumerable<T> and yield return currValue instead of adding it to the final list.

Upvotes: 2

Jerod Houghtelling
Jerod Houghtelling

Reputation: 4867

Use the Distinct method that is found with Linq. Here is an example using a list of ints.

Using System.Linq;

List<int> list = new List<int> { 1, 2, 3, 1, 3, 5 };
List<int> distinctList = list.Distinct().ToList();

Upvotes: 5

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