Convert range of number in string to list of integer

Question

I have a string "2-6,8,10-15,20-23"

I need to have it converted to a fully populated range of numbers in an array as below:

{2,3,4,5,6,8,10,11,12,13,14,15,20,21,22,23}

Do you have any ideas how to convert it?

Answer 1

Mark Heath has a course on LINQ at PluralSight that addresses this very well. Using LINQ, you can quickly do this using the example shown below.

string value = "7-10,2,5,12,17-18";
var result = value.Split(',')
                  .Select(x => x.Split('-'))
                  .Select(p => new { First = int.Parse(p.First()), Last = int.Parse(p.Last()) })
                  .SelectMany(x => Enumerable.Range(x.First, x.Last - x.First + 1))
                  .OrderBy(z=>z);

The Split creates an array out of the string. The first Select creates an array of arrays that have 1 or 2 elements apiece. The second Select creates an anonymous type indicating the starting and ending value based on the array values. The SelectMany uses the Enumerable.Range method to create a range of numbers from each anonymous object, then flattens it into an IEnumerable collection of integers. Finally, the OrderBy puts the numbers in order for reporting and other use.