在数组中查找最高和最低值并删除它们以计算平均 C#

Question

I am trying to write code that finds the lowest and highest values stored in an array and then removes them from the array to compute an average.

Currently I have written code to produce the average of all numbers in the array but I need to change that once I figure out how to remove Highest and lowest value.

Code I have:

private void HighAndLow()
{
    try
    {
        int[] HighAndLowGrade;
        int[] highest = HighAndLowGrade.Max();
        int lowest = HighAndLowGrade.Min();
    }
    catch
    {
        MessageBox.Show("HighAndLow Method failed");
    }
}
        
//find average without highest and lowest values
private void ComputeMean()
{
    double total = 0;
    for (int index = 2; index < 9; index ++)
    {
        total += double.Parse(lineContent[index]);
    }
    averageTestScore = total / 7;
 }

Answer 1

This only requires one iteration through the collection:

public double ComputeAdjustedMean(IEnumerable<int> items)
{
    int total = 0;
    int count = 0;
    int min = int.MaxValue;
    int max = int.MinValue;

    foreach(int item in items)
    {
        count++;
        total += item;
        if (item < min) min = item;
        if (item > max) max = item;
    }

    if (count <= 2) // not enough items
    {
       // do something here
    }
    return (total - (min + max)) / (double)(count - 2);
}

    

Answer 2

This should work from what I have tested so far.

int[] numberArray = new int[] {1,2,5,9,5,2};
double answer = 0;

var ignoreList = new List<decimal>() {
    numberArray.Max(),
    numberArray.Min()
};

var cleanList = numberArray.Where(x => !ignoreList.Contains(x));

answer = cleanList.Any() ? cleanList.Average() : 0;

Answer 3

Try this using bubble sorting algorithm-

 static void Main(string[] args)
    {
        int[] array = { 12, 6, 34, 23, 89 };
        int temp;


            for (int i = 0; i <= array.Length - 2; i++)
            {
                if (array[i] > array[i + 1])
                {
                    temp = array[i];
                    array[i] = array[i + 1];
                    array[i + 1] = temp;
                }
            }
        array = array.Skip(1).SkipLast(1).ToArray();
        Console.WriteLine((array.Sum()) / (array.Length));
        Console.Read();
    }

Answer 4

If you have an array of values then you can do this neat LINQ query:

var average_skip_min_and_max =
    values
        .OrderBy(x => x)
        .Skip(1)
        .Take(values.Length - 2)
        .Average();

Answer 5

I really don't get people when they encounter this kind of questions, they became insanely eager to provide a direct answer . This question is obviously a homework assignment. I'm not saying we don't help OPs but we need to lead them to solutions.

Dear OP,

Do not use the LINQ, yet . I think your instructor is meaning you to learn the sorting algorithms and memory operations. Do some research about them, say, Buble Sort , to sort the array you have. Then it'll be in front of you how to implement and use. After then, you should use the framework provided methods like LINQ's Min() / Max() extension methods.

The approach to your problem is could be like this:

1. Sort the array ascending.
2. Get the first element which is now the minimum valued element.
3. Reallocate a new array but 1 element shorter
4. Copy your entire array with the current ordered state to newly allocated array but skip the first element when copying, start with next element.
5. Get the minimum again, but this time search in the newly allocated array and check with the previous minimum
   • If they are equal go the 3rd operation, if you need to eliminate the repeating minimums ( [1, 1, 2, 3 ...] ), which I think you need to.
   • If they are not equal, then it means you've found the minimum element of your array and removed all occurences

Now if you repeat the approach to finding the maximum valued element you are done with the elimination process.