How do I find the mode of a list<double>?

mode of a list python
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how to print the mode in python

I have a list:

List<double> final=new List<double>();
final.Add(1);
final.Add(2);
final.Add(3);

What sort of method could I use to find the mode of this list? Also, if there are two modes, the function would return the smaller of the two.

int? modeValue =
 final
 .GroupBy(x => x)
 .OrderByDescending(x => x.Count()).ThenBy(x => x.Key)
 .Select(x => (int?)x.Key)
 .FirstOrDefault();

All it takes are a few composed LINQ operations. You can also express the same with query expressions.

If the list is empty, modeValue will be null.

Finding the mode of a list, MathHelp.com. There are nine numbers in the list, so the middle one will be the (9 + 1) ÷ 2 = 10 ÷ 2 = 5th number: So the median is 14. The mode is the number that is repeated more often than any other, so 13 is the mode. The largest value in the list is 21, and the smallest is 13, so the range is 21 – 13 = 8. 1. An alternative solution: var counts = final .Distinct() .Select(o => new { Value = o, Count = final.Count(c => c == o) }) .OrderByDescending(o => o.Count); This will return a collection indicating how many times each of the values appears in the list, with the most popular (mean) first.

The answer given by usr seems like it would do the trick, but if you are wanting something non-Linq, try this:

    public int? FindMode(List<int> sample)
    {
        if (sample == null || sample.Count == 0)
        {
            return null;
        }

        List<int> indices = new List<int>();
        sample.Sort();

        //Calculate the Discrete derivative of the sample and record the indices
        //where it is positive.
        for (int i = 0; i < sample.Count; i++)
        {
            int derivative;

            if (i == sample.Count - 1)
            {
                //This ensures that there is a positive derivative for the
                //last item in the sample. Without this, the mode could not
                //also be the largest value in the sample.
                derivative = int.MaxValue - sample[i];
            }
            else
            {
                derivative = sample[i + 1] - sample[i];
            }

            if (derivative > 0)
            {
                indices.Add(i + 1);
            }
        }

        int maxDerivative = 0, maxDerivativeIndex = -1;

        //Calculate the discrete derivative of the indices, recording its
        //maxima and index.
        for (int i = -1; i < indices.Count - 1; i++)
        {
            int derivative;

            if (i == -1)
            {
                derivative = indices[0];
            }
            else
            {
                derivative = indices[i + 1] - indices[i];
            }

            if (derivative > maxDerivative)
            {
                maxDerivative = derivative;
                maxDerivativeIndex = i + 1;
            }
        }

        //The mode is then the value of the sample indexed by the
        //index of the largest derivative.
        return sample[indices[maxDerivativeIndex] - 1];
    }

What I've done here is essentially an implementation of the algorithm described on the Wikipedia page in the section Mode of a sample. Note that by sorting the sample first, this will return the smaller mode in the multi-mode case.

Also, the Octave code on the Wikipedia page assumes 1-based indexing; because C# is 0-based, you'll see I used indices.Add(i + 1) and maxDerivativeIndex = i + 1 to compensate. For the same reason I also used indices[maxDerivativeIndex] - 1 to map back to 0-based indexing when returning the final mode.


Because this method is a little less obvious than the intuitive method of using a Dictionary to accumulate counts, here is a sort of worked example.

Calling the above method:

int? mode = FindMode(new List<int>(new int[] { 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17 }));

After that initial check and sort, the discrete derivative (i.e., the indices list) will look like this at the end of that first for loop:

[1, 2, 6, 8, 10, 11]

Next, we calculate the discrete derivative of indices. For efficiency reasons I am not storing these in a list (we only want the largest of them, after all), but they work out to be:

[1, 1, 4, 2, 2, 1]

Therefore, maxDerivative ends up being 4, and maxDerivativeIndex 2. Hence:

sample[indices[maxDerivativeIndex] - 1]
    -> sample[indices[2] - 1]
    -> sample[6 - 1]
    -> 6

Mean, Median, Mode, and Range, We'll learn how to recognize the mode, as well as learn about bi-modal lists with two short Duration: 2:55 Posted: Feb 7, 2015 Finding the Mode. To find the mode, or modal value, it is best to put the numbers in order. Then count how many of each number. A number that appears most often is the mode.

An alternative solution:

var counts = final
    .Distinct()
    .Select(o => new { Value = o, Count = final.Count(c => c == o) })
    .OrderByDescending(o => o.Count);

This will return a collection indicating how many times each of the values appears in the list, with the most popular (mean) first. You can get to this using counts.FirstOrDefault();, but a collection may be more useful as you'll be able to see when there is more than one mode!

I find GroupBy LINQ queries can be a bit tricky to understand, but that's my personal opinion.

Finding the Mode of a List of Numbers, We define a list of numbers and calculate the length of the list. We then use sum() function to get sum of all the elements in a list. We finally divide the total sum by  Use a dictionary with the value as the key and a count as value. If you're using Python 3, this is the Counter data type. When you've tallied all the entries, find the max of the values. Make a list comprehension of all elements with that value.

An alternative solution that is more correct due to the other methods not returning all numbers if they occur the same amount of times

Input: 1,2,3,4,5

Output: 1,2,3,4,5

Input: 1,1,2,2

Output: 1,2

Input: 1,1,2,4,5 Output 1

string getMode()
    {
        IDictionary<float, int> mode = new Dictionary<float, int>();    //Dictionary (Float is the number) (Int is  the occurences)
        foreach (float number in numbers)                               //Loop through List named numbers (List is made of floats)
        {
            if (mode.ContainsKey(number))                               //If dictionary already contains current number increase occurences by 1
            {
                mode[number] ++;
            }
            else
            {
                mode.Add(number, 1);                                    //If dictionary does not contain current number add new occurence
            }
        }

        List<float> currentMax = new List<float>();                     //Create new List of the max number
        int occurences = 0;                                             //Max occurences
        bool foundMultiple = false;                                     //Check if multiple found
        foreach (KeyValuePair<float, int> entry in mode.Reverse())      //Loop through dictionary
        {
            if(occurences < entry.Value)                                //If occurences is smaller than current input
                                                                        //Clear old input and add current number to list
            {
                currentMax.Clear();
                currentMax.Add(entry.Key);
                occurences = entry.Value;
                foundMultiple = false;
            }
            else if(occurences == entry.Value)                          //If number with the same amount of occurences occures
                                                                        //Add to List
            {
                currentMax.Add(entry.Key);
                foundMultiple = true;
            }
        }

        string returnText = "";                                         //Text to return
        if(foundMultiple == true)                                           
        {
           foreach(float number in currentMax)                          //Loop through text
            {
                returnText += number.ToString() + ",";                  //Add to return text
            }
        }
        else
        {
            returnText = currentMax[0].ToString();                         //If there aren't multiple return just first index
        }

        if (returnText.EndsWith(","))
        {
            returnText = returnText.Remove(returnText.Length - 1);      //Format string to avoid a comma at the end
        }
        return returnText;
    }

Finding Mean, Median, Mode in Python without libraries , Syntax : mode([data-set]) Parameters : [data-set] which is a tuple, list or a iterator of real valued numbers as well as Strings. Return type : Returns the  The mode of a data set is the number that occurs most frequently in the set. To easily find the mode, put the numbers in order from least to greatest and count how many times each number occurs. The number that occurs the most is the mode!

Python statistics, List the data values in numerical order. Count the number of times each value appears. The mode is the value with the highest frequency. example. The  Find the mode for text values from a list/column with formula Find the mode for text values from a list /column with Kutools for Excel Easily sort by frequency of occurrences in Excel Kutools for Excel's Advanced Sort utility supports sorting data by text length, last name, absolute value, frequency, etc. in Excel quickly.

Identifying the Mode of a Set of Numbers, Modes are typically taken from sets of statistical data points or lists of numerical values. Thus, to find a mode, you'll need a data set to find it for. The fifth and sixth numbers are the last 10 and the first 11, so: (10 + 11) ÷ 2 = 21 ÷ 2 = 10.5. The mode is the number repeated most often. This list has two values that are repeated three times; namely, 10 and 11, each repeated three times. The largest value is 13 and the smallest is 8, so the range is 13 – 8 = 5.

How to Find the Mode of a Set of Numbers: 8 Steps (with Pictures), Mode is described as the most frequent occurring number when all numbers are sorted from Duration: 14:26 Posted: Apr 30, 2019 The mode is the number in a data set that occurs most frequently. Count how many times each number occurs in the data set. The mode is the number with the highest tally. It's ok if there is more than one mode. And if all numbers occur the same number of times there is no mode. How to Find the Mean. Add up all data values to get the sum

Comments
  • What is the List mode?
  • I think he means the element that appears in the list most often. Have a look at: en.wikipedia.org/wiki/Mode_%28statistics%29
  • You can explain a lttle more about mode
  • @Edward: What are you looking for besides usr's answer?
  • If you don't already know about LINQ, you might want to make yourself familiar with it. int? is a nullable type.
  • @EdwardKarak Nullable types are explained here msdn.microsoft.com/en-us/library/1t3y8s4s.aspx
  • what about var distinct=final.Distinct(); var modes=distinct.Except<int>(distinct);