Check for missing number in sequence

Question

I have an List which contains 1,2,4,7,9 for example.

I have a range from 0 to 10.

Is there a way to determine what numbers are missin

Answer 1

Turn the range you want to check into a HashSet:

public IEnumerable FindMissing(IEnumerable values)
{
  HashSet myRange = new HashSet(Enumerable.Range(0,10));
  myRange.ExceptWith(values);
  return myRange;
}

Will return the values that aren't in values.