CODEWITHSUNDEEP
c#
user2886946
user2886946

Reputation: 41

Find most common element in array

I have a string array that can contains 1 or more elements with various string values. I need to find the most common string in the array.

string aPOS[] = new string[]{"11","11","18","18","11","11"};

I need to return "11" in this case.

Upvotes: 3

Views: 5318

Answers (3)

TheTerribleProgrammer
TheTerribleProgrammer

Reputation: 546

If you don't like using LINQ or are using e.g. .Net 2.0 which does not have LINQ, you can use foreach loops

string[] aPOS = new string[] { "11", "11", "18", "18", "11", "11"};
        var count = new Dictionary<string, int>();
        foreach (string value in aPOS)
        {
            if (count.ContainsKey(value))
            {
                count[value]++;
            }
            else
            {
                count.Add(value, 1);
            }
        }
        string mostCommonString = String.Empty;
        int highestCount = 0;
        foreach (KeyValuePair<string, int> pair in count)
        {
            if (pair.Value > highestCount)
            {
                mostCommonString = pair.Key;
                highestCount = pair.Value;
            }
        }

Upvotes: 1

Jason
Jason

Reputation: 15931

You can do this with LINQ, the following is untested, but it should put you on the right track

var results = aPOS.GroupBy(v=>v) // group the array by value
                     .Select(g => new { // for each group select the value (key) and the number of items into an anonymous object
                                   Key = g.Key,
                                   Count = g.Count()
                                   })
                      .OrderByDescending(o=>o.Count); // order the results by count

// results contains the enumerable [{Key = "11", Count = 4}, {Key="18", Count=2}]

Here's the official Group By documentation

Upvotes: 0

Ryan Schlueter
Ryan Schlueter

Reputation: 2221

Try something like this using LINQ.

int mode = aPOS.GroupBy(v => v)
            .OrderByDescending(g => g.Count())
            .First()
            .Key;

Upvotes: 19

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