Getting unmatched array from two array objects

Question

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {

        string Card = (Request.Params["Card"]);
        DateTime Date = DateTime.Parse(Request.Params["Date"]);

        using ( AttendanceContext db = new AttendanceContext())
        {
            lblEmpName.Text = db.users.Where(t => t.Card == Card).SingleOrDefault().EmployeeName;
            lblDate.Text = Date.ToString("dd/MM/yyyy");
            if (lblEmpName.Text == null)
            {
                lblEmpName.Text = "No Data";
            }
            if (lblDate.Text == null)
            {
                lblDate.Text = "No Date";
            }

            var firstArray = db.TimeoutJustification.Where(x => x.Date == Date && x.Card == Card && x.GeneralJustification != null).ToList();

            var SecondArray = GetTimeOutData(Card, Date).OrderByDescending(t => t.Date).ToList();

            ///This is where i need to check both arrays
            var filtered = firstArray.Except(SecondArray);
            //var d = newTimeoutdata.Where(t => !newTimeoutdata.Contains(t.TimeOut.ToString())).ToList();
            if(filtered!=null){
                //This is where i will insert the unmatched array
                db.TimeoutJustification.AddRange(filtered);
                db.SaveChanges();
            }
        }

    }
}
}

My first array contains 3 items that are identical to 3 of the items in my second array.

I need to get the 4th unmatched item from my second array only. keep in mind that I need to compare both arrays a using datetime TimeOut since date and card will always be the same in all arrays

Does this answer your question? c# linq - get elements from array which do not exist in a different array — Heretic Monkey
– Heretic Monkey, Commented Dec 11, 2019 at 14:05
Or Getting the “diff” between two arrays in C#?, or Use LINQ to get items in one List, that are not in another List, or Using LINQ to Objects to find items in one collection that do not match another, or LINQ - Find all items in one list that aren't in another list — Heretic Monkey
– Heretic Monkey, Commented Dec 11, 2019 at 14:21

Salah Akbari · Accepted Answer · 2019-12-11 14:41:44Z

1

You can use the Except method, something like this:

secondArray.Except(firstArray)

However you might also need to use a custom equality comparer for this purpose. I am not sure about your properties inside your class, you can do something like this for instance:

public class DistinctItemComparer : IEqualityComparer<yourClass>
{

    public bool Equals(yourClass x, yourClass y)
    {
        return x.Id == y.Id &&
            x.Date == y.Date &&
            x.Card == y.Card;
    }

    public int GetHashCode(yourClass obj)
    {
        return obj.Id.GetHashCode() ^
            obj.Date.GetHashCode() ^
            obj.Card.GetHashCode();
    }
}

And then using it like this:

secondArray.Except(firstArray, new DistinctItemComparer())

edited Dec 11, 2019 at 14:41

answered Dec 11, 2019 at 14:02

Salah Akbari

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2 Comments

Natrium Over a year ago

learn.microsoft.com/en-us/dotnet/csharp/programming-guide/…

Sam Over a year ago

Thank you so much @SalahAkbari

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