Sort String Array As Int

Question

Is there some way to use IComparer with ArrayList.Sort() to sort a group of strings as ints?

Answer 1

Sure. Just create the appropriate comparer that does the conversion.

public class StringAsIntComparer : IComparer {
  public int Compare(object l, object r) {
    int left = Int32.Parse((string)l);
    int right = Int32.Parse((string)r);
    return left.CompareTo(right);
}

Answer 2

If they are all strings, why are you using an ArrayList? If you're on .Net 2.0 or later, List<string> is a much better choice.

If you're on .Net 3.5 or later:

var result = MyList.OrderBy(o => int.Parse(o.ToString() ) ).ToList();

Answer 3

A slight variation based on Joel's solution

string[] strNums = {"111","32","33","545","1","" ,"23",null};
    var nums = strNums.Where( s => 
  {
  int result;
  return !string.IsNullOrEmpty(s) && int.TryParse(s,out result);
  }
 )
 .Select(s => int.Parse(s))
 .OrderBy(n => n);

 foreach(int num in nums)
 {
     Console.WriteLine(num);
 }