C# parsing page-number strings. Esto retorna: Hello World 1 2 3 4 3 5 6 7 8 9 10 12

parsingPageNumbersString.cs

using System;
using System.Collections.Generic;		
using System.Linq;
public class Program
{
	public static void Main()
	{
		Console.WriteLine("Hello World");
		var result = GetNumbers("1-4,3,5-10,12");
		
		foreach (var item in result){
			Console.WriteLine(item);
		}
	}
	
	public static IEnumerable<int> GetNumbers(string pagesToExtract){
	
		
		foreach( string s in pagesToExtract.Split(',') ) 
{
    // try and get the number
    int num;
    if( int.TryParse( s, out num ) )
    {
        yield return num;
        continue; // skip the rest
    }

    // otherwise we might have a range
    // split on the range delimiter
    string[] subs = s.Split('-');
    int start, end;

    // now see if we can parse a start and end
    if( subs.Length > 1 &&
        int.TryParse(subs[0], out start) &&
        int.TryParse(subs[1], out end) &&
        end >= start )
    {
        // create a range between the two values
        int rangeLength = end - start + 1;
        foreach(int i in Enumerable.Range(start, rangeLength))
        {
            yield return i;
        }
    }
}
		
	}
}