Count forward and backward string

Question

Hi All,
How to count in three 3 number forward and backwark.
By click button1 the result show

698 = 6
075 = 5
150 = 4

here code;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Checking_12  
{  
    public partial class Form1 : Form  
    {  
        //..Text File=" 968, 986, 698, 689, 896, 869, 075, 051, 057, 105, 150, 705, 750, 501, 507 "  
  
        public Form1()  
        {  
            InitializeComponent();  
        }  
  
        private void Form1_Load(object sender, EventArgs e)  
        {  
            foreach (var s in File.ReadLines(@"D:\Ro.txt"))  
            {  
                listBox1.Items.Add(s);  
            }  
        }  
  
        private void button1_Click(object sender, EventArgs e)  
        {  
  
            var count = listBox1.Items.ToString().Split(new[] { ',', ':' });  
            var count_ = count.Where(s => s.Count().ToString() ="xxx");  
            listBox2.Items.Add(count_);  
        }  
  
    }  
}  
  

Answer 1

Try an alternative suggestion too:

private void button1_Click( object sender, EventArgs e )  
{  
    var r = listBox1.Items  
        .Cast<string>( )  
        .Select( i => i.Split( ',' ).Select( n => string.Concat( n.Trim( ).OrderBy( c => c ) ) ) )  
        .SelectMany( a => a )  
        .GroupBy( n => n )  
        .Select( g => new { n = g.Key, c = g.Count( ) } );  
  
    listBox2.Items.AddRange( r.Select( z => $"{z.n} = {z.c}" ).ToArray( ) );  
}  

Answer 2

How to count in three 3 number forward and backward.

Your example is very confusing as it counts backward by 5 first then by 4 not 3! It is not clear how you get 6, 5, 4 or what these values represent and why you are using a listbox when you have one item in the listbox1.

This is a very basic math question. I'll assume you want to count backward by 3 as stated in your post. There are 15 items in the collection so the first item is 15-(3*i)= 12 where i =1. The second item is 15-(2*i) = 9 where i = 2. Simply do the math until the results of the addition/subtraction is less than or equal to 0. In your button click simply increment i. The following example counts backward. To count forward the index math is simply (i*3) where i starts at 0.

    public partial class Form1 : Form  
    {  
        private int i;  
        private int totalItems;  
        private List<string> items;  
        private const int backwardCount = 3;  

        public Form1()  
        {  
            InitializeComponent();  
            i = 1;  
        }  

        private void Form1_Load(object sender, EventArgs e)  
        {  
            foreach (var s in File.ReadLines(@"Ro.txt"))  
            {  
                listBox1.Items.Add(s);  
            }  

            items = listBox1.Items[0].ToString().Split(new[] { ',', ':' }).ToList();  
            totalItems = items.Count();  
        }  

        private void button1_Click(object sender, EventArgs e)  
        {  
            int idx = totalItems - (backwardCount * i++);  
            label1.Text = idx.ToString();  
            if(idx >= 0)  
            {  
                listBox2.Items.Add(items[idx]);  
            }  

        }  
    }  

If the code does not meet your requirements, I'm sure you can tweak the code to suite your needs since all you're doing is basic addition and subtraction.

Answer 3

Another option is to use Chunk and Reverse done here with .NET Core 6. Extra blank entries are for clarity.

using System.ComponentModel;  
  
namespace WinFormsApp3;  
  
public partial class Form1 : Form  
{  
    private readonly BindingList<string> _bindingList1 = new();  
    private readonly BindingList<string> _bindingList2 = new();  
    private readonly BindingSource _bindingSource1 = new();  
    private readonly BindingSource _bindingSource2 = new();  
    public Form1()  
    {  
              
        InitializeComponent();  
  
        _bindingSource1.DataSource = _bindingList1;  
        _bindingSource2.DataSource = _bindingList2;  
  
        listBox1.DataSource = _bindingSource1;  
        listBox2.DataSource = _bindingSource2;  
    }  
  
    private void ChunkButton_Click(object sender, EventArgs e)  
    {  
        var container = " 968, 986, 698, 689, 896, 869, 075, 051, 057, 105, 150, 705, 750, 501, 507"  
            .Split(',')  
            .Select(x => x)  
            .ToList();  
  
        var chunked = container.Chunk(3).ToList();  
  
        foreach (var chunker in chunked)  
        {  
            foreach (var data in chunker)  
            {  
                _bindingList1.Add(data);  
            }  
  
            _bindingList1.Add("");  
        }  
  
        chunked.Reverse();  
  
        foreach (var chunker in chunked)  
        {  
            foreach (var data in chunker)  
            {  
                _bindingList2.Add(data);  
            }  
  
            _bindingList2.Add("");  
        }  
  
    }  
}