Sorting Arraylist collection having items as Strings

similar kind of question and some accepted solutions can be found in below link

c# linq orderby numbers that are string (and you cannot convert them to int)

You can use IComparable to implement custom sorting for your class. Basicaly, IComparable allows custom sorting of objects when implemented.

Just check the following Example:

class Employee : IComparable<Employee>
{
public int Salary { get; set; }
public string Name { get; set; }

public int CompareTo(Employee other)
{
    // Alphabetic sort if salary is equal. [A to Z]
    if (this.Salary == other.Salary)
    {
        return this.Name.CompareTo(other.Name);
    }
    // Default to salary sort. [High to low]
    return other.Salary.CompareTo(this.Salary);
}
}

Regards.

What you are trying to do is called Natural sort
There is a NuGet package for .Net implementation

Then you can sort your array very easy

arr.OrderBy(x => x, StringComparer.OrdinalIgnoreCase.WithNaturalSort());

Here you are, without any external packages:

     class Program
  {
    static void Main(string[] args)
    {
      // Initializing your list of strings
      List<string> list = new List<string>()
      {
        "M9", "M2", "M7", "M11", "M5", "M6", "M3", "M8", "M1", "M10", "M4", "M12"
      };

      SortStringList(list);
    }

    private static void SortStringList(List<string> list)
    {
      // Bubble sort
      bool change = true;

      while (change)
      {
        change = false;
        for (int i = 0; i < list.Count; i++)
        {
          if (i + 1 < list.Count)
          {
            // here im converting the string to a number removing the first char "M"
            int currentElement = Convert.ToInt32(list[i].Remove(0, 1));
            int nextElement = Convert.ToInt32(list[i + 1].Remove(0, 1));
            // comparing two integers and swapping the strings elements
            if (currentElement > nextElement)
            {
              string tmp = list[i];
              list[i] = list[i + 1];
              list[i + 1] = tmp;
              change = true;
            }
          }
        }
      }
    }
  }

OrderBy with custom IComparer could be useful. Try this:

var list = new List<string> { "M10", "M2", "M9", "M1", "M22" };
Console.WriteLine(string.Join(", ", list.OrderBy(_ => _, new Comparer())));
// M1, M2, M9, M10, M22

Where custom IComparer<string> could be implemented like this:

class Comparer : IComparer<string>
{
    public int Compare(string x, string y) 
        => x.Length != y.Length ? x.Length - y.Length : string.Compare(x, y);
}