Calculate Mode Using LINQ C#

Question

I'm new with using Linq and was wondering how I could print out multiple values of my Mode value. At the minute I can only get 1 value from the Mode but I want it to show multiples ones.

string[] list = TextBox1.Text.Split(new string[] { "," }, 
    StringSplitOptions.RemoveEmptyEntries);
int[] numbers = new int[list.Length];
for (int i = 0; i < numbers.Length; i++)
{
    numbers[i] = Convert.ToInt32(list[i].Trim());
}
int mode = numbers.GroupBy(v => v)
                  .OrderByDescending(g => g.Count())
                  .First()
                  .Key;

You use `First`, that's why you get only one. Use `Select(g => g.Key)` and then loop the result — Tim Schmelter, Nov 29 '18 at 14:48
I know it is not the main topic of your question, but what if you use string[] list = Textbox1.Text.split(',');?? — ger, Nov 29 '18 at 14:52
https://stackoverflow.com/questions/5069687, https://stackoverflow.com/questions/355945, https://stackoverflow.com/questions/8260555 — Drag and Drop, Nov 29 '18 at 15:00
Possible duplicate of [Find character with most occurrences in string with C#?](https://stackoverflow.com/questions/5069687/find-character-with-most-occurrences-in-string-with-c) — Drag and Drop, Nov 29 '18 at 15:02
In the linked duplicate consider a string as an array a char like your numbers is an array of int. — Drag and Drop, Nov 29 '18 at 15:03
Those answers sems to be the best fit for your question with complete answer : https://stackoverflow.com/a/16817294/6560478 , https://stackoverflow.com/a/16818909/6560478 — Drag and Drop, Nov 29 '18 at 15:06

Nathan Werry · Answer 1 · 2018-11-29T21:28:48.327

0

You need to save off the collection before taking the item(s) you want.

string[] list = TextBox1.Text.Split(new string[] { "," }, 
  StringSplitOptions.RemoveEmptyEntries);
IEnumerable<IGrouping<int, int>> modes = list.GroupBy(v => v);
IEnumerable<IGrouping<int, IGrouping<int, int>>> groupedModes = modes.GroupBy(v => v.Count());
var sortedGroupedModes = groupedModes.OrderByDescending(g => g.Key).ToList();

TextBox2.Text = string.Join(" ", sortedGroupedModes[0].Select(x => x.Key)));

edited Nov 29 '18 at 21:28

answered Nov 29 '18 at 14:54

Nathan Werry

876
7
18

Getting an error: Cannot implicitly convert type 'System.Linq.IOrderedEnumerable to 'System.Collctions.Generic.IEnumerable' when implmenting your changes. – Swail Nov 29 '18 at 15:01
I have corrected the errors, sorry. If you want distinct values of the mode in order, then you can add a `.Distinct()` between the `.SelectMany()` and the `.ToList()` – Nathan Werry Nov 29 '18 at 15:22
Thanks Nathan you are a star! Finally I was hoping to output the result into a textbox instead of the console: TextBox2.Text = modes.ToString();. What way would I go about this? – Swail Nov 29 '18 at 15:27
I am not sure on your format that you need it in the textbox, but if you need it just how your example details then: `TextBox2.Text = modes[0].ToString();` – Nathan Werry Nov 29 '18 at 15:30

score -1 · Answer 2 · answered Nov 29 '18 at 15:02

-1

You could get all of the groups and just extract those with the highest count (including ties):

var counts = numbers.GroupBy(v => v)
                    .Select(g => g.Key, Count = g.Count())
                    .OrderByDescending(g => g.Count);

var modes = numbers.Where(g => g.Count == counts.First().Count)
                   .Select(g => g.Key);

answered Nov 29 '18 at 15:02

D Stanley

149,601
11
178
240

Where would i initilaise Count variable ? – Swail Nov 29 '18 at 15:07
@Swail it's initialized in the `Select` of the first query. – D Stanley Nov 29 '18 at 16:26

Calculate Mode Using LINQ C#

2 Answers2

Linked