How Can I Use Rank Function With Array?

Hi,

You need to pass an excel range object as the second argument . Please refer below link for details on Excel Rank function.

https://msdn.microsoft.com/en-us/library/office/ff840358.aspx[^]

Please refer below code and see how Range is set and used as an argument for Rank() function .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Excel= Microsoft.Office.Interop.Excel;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] list = new int[] { 6, 50, 99, 35, 1, 2, 7 };

                     
           Excel.Application xlApp = new Excel.Application();
           xlApp.Visible = true;
           Excel.Workbook xlWb = xlApp.Workbooks.Add() as Excel.Workbook;
           Excel.Worksheet xlSheet = xlWb.Sheets[1] as Excel.Worksheet;
           Microsoft.Office.Interop.Excel.WorksheetFunction wsf1 = xlApp.WorksheetFunction;


           Excel.Range range = xlSheet.get_Range("A1:A7");

           for (int i = 0; i < list.Count();i++)
           {
               range.Cells[i+1] = list[i];
              
           }
            
           for (int i = 0; i < list.Count(); i++)
           {
               Console.WriteLine(" {0} -  Rank is  : {1} ", list[i] ,wsf1.Rank(list[i], range.get_Range("A1:A7"),0));
               
           }

             //  xlWb.Close(SaveChanges:false);
            //   xlApp.Visible = false;
             //  xlApp = null;

            Console.ReadKey();
        }
    }
}

I do not recommend to use any specific library, unless it's standard .net.

Based on your requirements, i'd suggest to use "index":

int[] list = new int[] {6,50,99,35,1,2,7};

var qry = list
            .OrderBy(i=>i)
            .Select((i, index)=>new
                {
                    number = i,
                    rank = index+1
                });

Result:

number rank
1      1
2      2
6      3
7      4
35     5
50     6
99     7

Note, you can always write extension method[^].