Test if a list of dates is sorted 1

[graabein]

Hi, I'm pretty new to C# .Net 3.5 so go easy on me... I want to test if a list of dates is sorted.

I use LINQ to extract the DateTime field from a ObservableCollection<T> with either ToArray or ToList. I do this twice, with and without orderby clause.

The (simple?) problem is how do I compare the two lists?

Is this even the best way to attack this?


graabein

 

[graabein]

Here is what I've got so far but it's probably not the best way to go about this. Suggestions are welcome!

private bool IsSorted(ObservableCollection<CustomEntity> coll)
{
    List<DateTime> unsorted = (from n in coll 
        where n.EventDateTime > DateTime.MinValue 
        select n.EventDateTime).ToList<DateTime>();
            
    List<DateTime> sorted = (from n in coll 
        where n.EventDateTime > DateTime.MinValue 
        orderby n.EventDateTime 
        select n.EventDateTime).ToList<DateTime>();

    for (int i = 0; i < unsorted.Count; i++)
    {
        if (unsorted[i] != sorted[i])
        {
            return false;
        }
    }
    return true;
}

graabein

 

[jmeckley]

why do you need to know if the list is sorted. just sort the list.

Jason Meckley
Programmer
Specialty Bakers, Inc.

faq855-7190

 

[graabein]

The user registers a list of dates. I want to see if they are in order.


graabein

 

[jmeckley]

why not just sort them then? then they are in order. adding the complexity of knowing if they are sorted seems extraneous.

however, here is more condensed code.

private bool IsSorted(IEnumerable<CustomEntity> items)
{
   var previous = DateTime.MinValue;
   foreach(var item in items)
   {
      if(previous > item.EventDateTime) return false;
      previous = item.EventDateTime;
   }
   return true;
}

Jason Meckley
Programmer
Specialty Bakers, Inc.

faq855-7190

 

[graabein]

Well I'm trying to write some tests to run on the code (not written yet). They're not registrations of the same thing, they're a series of events connected with a bigger operation so we need to know what happened when for later on. Some of these events have to be in the proper order.

Thanks for the code! It's so obvious I smacked my forehead. Been on holiday for too long I guess!


graabein