I have the a list called orderList of type Order which has two properties. The list looks something like below.
Id Status
123 Good
878 Good
432 Good
123 Void
What I would like to do is to remove any orders that have a Status which is void and any Good orders which have the same Id as a void order. So the result would give me,
Id Status
878 Good
432 Good
What is the best way to do this? Is it just getting a list of void orders using linq and then looping through this new list to remove Good orders which share the same Id?
You can group and filter later, and flatten the groups at the end:
var result= list.GroupBy(e=>e.Id)
.Where(g=>g.Any(r=>r.Status=="Good") && g.All(r=>r.Status!="Void"))
.SelectMany(g=>g);
So you need to group first by your ID, after that specified your data and create new Field Remove which should be true if you have any Status Void in your group status collection. After that take objects only where the Remove is false and in the end create your RootOrder.
var result = list.GroupBy(x => x.ID)
.Select(x => new { ID = x.Key, Status = x.FirstOrDefault().Status, Remove = x.Any(y => y.Status == "Void") })
.Where(g => g.Remove == false)
.Select(r => new RootOrder { ID = r.ID, Status = r.Status }).ToList();
Full code example: dotNetFiddle
One way would be grouping, filtering and flattening the remaining groups - If you want a more 'literal' query you can try the following:
First filter out all of the non-Good Orders using Where:
orderList = orderList.Where(x => x.Status == Status.Good)
Then filter out all of the remaining Orders for which there are non-Good Orders in orderList containing the same Id using Where and Any:
.Where(x => !orderList
.Any(y => y.Status == Status.Void && y.Id == x.Id)
Finally, use the ToList() to take the returned IEnumerable as a List:
orderList = orderList
.Where(x => x.Status == Status.Good)
.Where(x => !orderList
.Any(y => y.Status == Status.Void && y.Id == x.Id)
.ToList();
Related
Inside method I have a list that contains grouped data:
var listofData = _context.DBONE.where(x => x.Id==3 && x.Status!=0)
.GroupBy(x => new { x.Name, x.Class })
.Select(q => new { Result = q.ToList() }).ToList();
if (methodParam == 10)
{
data = listofData.Where(x => FunctionCheck(---CANNOT ACCESS THE FIELDS FROM GROUP DATA TO PASS AS PARAMETERS---) == 10).ToList();
}
And this is the function that will receive 2 parameter from the grouped data:
private int FunctionCheck(int id, string name)
{...}
But, I cannot access the desired field inside 'listofData'. I can access only in case the listofData is not using groupBy().
If I understand what you are trying to do correctly, you are able to access your data but you are actually creating a "list of a list"
Watch my example, I think I have reproduced your scenario here:
As you can see, I then have a "result" which contains a list of users where Id == 3. The problem is that you create a new anonymous object with a props that is a list. So if you try the last thing you see in my image above, I think you will be able to access your rows.
The reason is that after your GroupBy call, the result is of a grouping type - every item of your list is an Enumerable of the original item, so you would have to operate on that grouping in a following manner:
// Groups such that all items in that group pass your check
listofData
.Where(group => group.All(item => FunctionCheck(item.Id, item.Name) == 10))
.ToList();
// Groups where at least one item matches
listofData
.Where(group => group.Any(item => FunctionCheck(item.Id, item.Name) == 10))
.ToList();
The desired outcome is not really clear from the question but this is the step you are likely missing.
Another approach which might be potentially useful is pre-filter the colleciton of items before grouping them:
var listOfGroupedDatas = _context.DBONE
.Where(x => x.Id ==3 && x.Status != 0 && FunctionCheck(item.Id, item.Name) == 10)
.GroupBy(x => new { x.Name, x.Class })
.ToList();
// This will result in a list of groupings in which all items pass your check
I think you want to call SelectMany to project into one dimensional array.
var listofData = _context.DBONE.where(x => x.Id==3 && x.Status!=0)
.GroupBy(x => new { x.Name, x.Class })
.SelectMany(q => q.ToList()).ToList();
Consider the following LINQ statements:
var model = getModel();
// apptId is passed in, not the order, so get the related order id
var order = (model.getMyData
.Where(x => x.ApptId == apptId)
.Select(y => y.OrderId));
var orderId = 0;
var orderId = order.LastOrDefault();
// see if more than one appt is associated to the order
var apptOrders = (model.getMyData
.Where(x => x.OrderId == orderId)
.Select(y => new { y.OrderId, y.AppointmentsId }));
This code works as expected, but I could not help but think that there is a more efficient way to accomplish the goal ( one call to the db ).
Is there a way to combine the two LINQ statements above into one? For this question please assume I need to use LINQ.
You can use GroupBy method to group all orders by OrderId. After applying LastOrDefault and ToList will give you the same result which you get from above code.
Here is a sample code:
var apptOrders = model.getMyData
.Where(x => x.ApptId == apptId)
.GroupBy(s => s.OrderId)
.LastOrDefault().ToList();
Entity Framework can't translate LastOrDefault, but it can handle Contains with sub-queries, so lookup the OrderId as a query and filter the orders by that:
// apptId is passed in, not the order, so get the related order id
var orderId = model.getMyData
.Where(x => x.ApptId == apptId)
.Select(y => y.OrderId);
// see if more than one appt is associated to the order
var apptOrders = model.getMyData
.Where(a => orderId.Contains(a.OrderId))
.Select(a => a.ApptId);
It seems like this is all you need:
var apptOrders =
model
.getMyData
.Where(x => x.ApptId == apptId)
.Select(y => new { y.OrderId, y.AppointmentsId });
So I have a table like this:
Now I want distinct ShortCode order by the ID descending. In other words, the distinct last records. Like this:
So I tried GroupBy like:
var data = db.ShortCodes.GroupBy(x => x.ShortCode).Select(x => x.FirstOrDefault()).OrderByDescending(s=> s.ID);
This gave me distinct records but not the last ones, nor ordered by ID descending:
Now I also tried like suggested here
var data = db.ShortCodeManager
.GroupBy(s => s. ShortCode)
.Select(g => g.First())
.OrderByDescending(s => s.ID);
This gave me the error The method 'First' can only be used as a final query operation. Consider using the method 'FirstOrDefault' in this instance instead.
So I modified to FirstOrDefault() like:
var data = db.ShortCodeManager
.GroupBy(s => s. ShortCode)
.Select(g => g.FirstOrDefault())
.OrderByDescending(s => s.ID);
This also gave me distinct records but not the last records:
So finally I tried like suggested here:
var data = db.ShortCodeManager.Where(a => a.ID > 0).GroupBy(x => x.ShortCode).OrderByDescending(grp => grp.Max(g => g.ID)).Select(a => a.FirstOrDefault());
Again, this gave me distinct records but not the last ones, nor ordered by ID descending:
So how am I to write the query to get the result I want in Linq? Also note, I need more of the distinct last records than ordering by ID descending. If anyone also knows how to write it in raw SQL it might be useful as well.
This LINQ query should work for your case:
var result = db.ShortCodeManager
.GroupBy(x => x.ShortCode)
.Select(gr => new { Id = gr.Max(g => g.Id), ShortCode = gr.Key})
.ToList();
EDIT:
Based on your comment it looks like you need to cast anonymous object result to ShortCodeManagerModel type and then pass it to your view. So, somethin like this:
var result = db.ShortCodeManager
.GroupBy(x => x.ShortCode)
.Select(gr => new { Id = gr.Max(g => g.Id), ShortCode = gr.Key})
.ToList();
var model = result
.Select(x => new ShortCodeManagerModel { Id = x.Id, ShortCode = x.ShortCode })
.ToList();
And then pass model to you view.
I had written a Query in NHibernate as below:
var queryResult = CurrentSession.QueryOver()
.Where(r => r.StatusId == 1)
.JoinQueryOver(a => a.ActorList)
.Where(s=>s.IsActor==1)
.List()
.Distinct()
.ToList();
I am trying to retrieve only Where(s=>s.IsActor==1), But It Is Getting Records
Where(s=>s.IsActor==0) also...
How can I get only IsActor==1 records?
Thanks in Advance
You need to specify a predicate in the join, so that it is applied to the join not the top where:
(will look something like ...LEFT JOIN actor on actor.Id = p.ActorId AND IsActor = 1)
Actor actorAlias = null;
var queryResult = CurrentSession.QueryOver()
.Where(r => r.StatusId == 1)
.Left.JoinQueryOver(r => r.ActorList, () => actorAlias, a => a.IsActor==1)
.List()
.Distinct()
.ToList();
I have a list of type customer. I need to insert all values of the list in the database before checking if a customer with the same customer number exists for that particular client.
For that I am firing a query to get me all customers who are there in the database having customer number equal to ones in the list. The query I am writing is not working, here's the code.
CustomerRepository.Find(x => x.ClientId == clientId)
.Where(x => x.CustomerNumber.Contains(lstCustomersInserted.Select(c => c.CustomerNumber)));
Keep it simple:
var lstCustomerNumbers = lstCustomersInserted.Select(c => c.CustomerNumber);
var res = CustomerRepository.Where(x => x.ClientId == clientId && lstCustomerNumbers.Any(c => c == x.CustomerNumber));
I think you have it backwards. Try reversing the Contains.
Edit: I switched to using the generic predicate Exists instead of Contains based on the comment, so you can match a property.
CustomerRepository.Find(x => x.ClientId == clientId)
.Where(x => lstCustomersInserted.Exists(c => x.CustomerNumber == c.CustomerNumber));
How about an Except?
CustomerRepository.Select(x => x.ClientID)
.Except(lstCustomersInserted.Select(x => x.CustomerID));
This will return the IDs of the objects in the repo that don't exist in your lstCustomersInserted.