Question

I have a situation that is well explained in this question:

Range intersection / union

I need a C# implementation (a collection maybe) that takes a list of ranges (of ints) and do the union of them.
Then I need to iterate through all ints in this collection (also numbers between ranges)
Are there any library/implementation so that I don’t have to rewrite everything by myself?

Answer 1

The simplest thing that comes to my mind is to use Enumerable.Range, and then treat the different IEnumerable with standard linq operators. Something like:

var list = Enumerable.Range(1, 5)
.Concat(Enumerable.Range(7, 11))
.Concat(Enumerable.Range(13, 22))

foreach(var number in list)
  // Do something

Obviously you can use Union and Intersect as well… clearly you can also put your ranges in a List<IEnumerable<int>> or something similar and then iterate over the elements for producing a single list of the elements:

var ranges = new List<IEnumerable<int>> 
{ 
    Enumerable.Range(1, 5), 
    Enumerable.Range(7, 11), 
    Enumerable.Range(10, 22) 
};
var unionOfRanges = Enumerable.Empty<int>();

foreach(var range in ranges)
    unionOfRanges = unionOfRanges.Union(range);

foreach(var item in unionOfRanges)
    // Do something