Removing Duplicate rows from IEnumerable

Question

I would like to know how you would remove duplicate rows from a IEnumerable. I have this code:

public IEnumerable <Shipments> Shipments
        {
            get
            {
                Debug.Print("Initiated");
                
                foreach (var item in Loads)
                {
                    if (item.ShipTo.Contains(" "))
                    {
                        
                        foreach (var item2 in Routes.Where(d => d.DockCode == item.ShipTo.Substring(0, item.ShipTo.IndexOf(" ")) && d.CarrierDeparture.TimeOfDay == item.ShipTime.TimeOfDay))
                        {
                                yield return new Shipments() { Arrival = item2.CarrierArrival, Departure = item2.CarrierDeparture, Issuer = item.Customer, Destination = item.ShipTo, LoadType = item.LoadType };
                        }
                    }
                }
            }
        }

which gives me this data using it as a item source

My goal is to only return new shipment if one that is the same doesn't exist. How would I go about doing that?

Answer 1

You could create a class that implements IEqualityComparer<Routes>:

class RoutesComparer : IEqualityComparer<Routes>
{
    // Might want to add null checks here.
    public bool Equals(Routes route1, Routes route2) =>
        route1.DockCode == route2.DockCode
        && route1.CarrierArrival == route2.CarrierArrival;

    public int GetHashCode(Routes obj) =>
        obj.DockCode.GetHashCode() ^ (obj.CarrierArrival.GetHashCode() * 13);
}

Then pass that to .Distinct().

foreach (var item2 in Routes.Where(d => d.DockCode == item.ShipTo.Substring(0, item.ShipTo.IndexOf(" "))
    && d.CarrierDeparture.TimeOfDay == item.ShipTime.TimeOfDay).Distinct(new RoutesComparer()))