How to Check Whether an Array (or List) Contains Another an Array (List) Using LINQ

Question

I am trying to get the list of files (file is an entity) which has the selected services (service is another entity). The file can have many services.

I tried the following statement, but it does not give the correct results:

var _serviceTypes = viewModel.SelectedServiceTypes;
// _serviceTypes is an array of integers

var resultsTemp = repository.Files.Where(f => f.Services.Select(s => s.ServiceTypeID).Intersect(_serviceTypes).Any());

What am I missing?

EDIT:

_serviceTypes in an array of integers: {int[2]}

The files can have many services, each of which as one service type id (integer)

For instance, a file has two services in it: ambulance (service type id: 3) and hospitalization (service type id: 5). I want to get all the files which have both the services in it.

Are you trying to get all the files whose Id is inside the _serviceTypes list/array ? — Shyju
– Shyju, Commented Dec 6, 2017 at 14:21
Can you show what's in _serviceTypes when this runs, and what's in resultsTemp afterward? — David
– David, Commented Dec 6, 2017 at 14:25
What you have seems right. How do you know it is not correct? — Andrei
– Andrei, Commented Dec 6, 2017 at 14:27
Please be more precise. Should a single file contain any service from the list or all services from the list? — grek40
– grek40, Commented Dec 6, 2017 at 14:43
@grek40 The file should contain all the services from the list. — burakk
– burakk, Commented Dec 6, 2017 at 15:13

grek40 · Accepted Answer · 2017-12-06 15:17:23Z

1

Some of the following operations should answer your question:

// requested IDs
var requestedIDs = new List<int>();
// the IDs from one file
var IDsInFile = new List<int>();
if (requestedIDs.Except(IDsInFile).Any())
{
    // at least some requested IDs are not in the file
}
else
{
    // all requested IDs are in the file
}
if (requestedIDs.Intersect(IDsInFile).Any())
{
    // at least some requested IDs are in the file
}
else
{
    // not a single requested ID is in the file
}

Since you want every file that contains all of the requested services, the correct query would be

var _serviceTypes = viewModel.SelectedServiceTypes;
// _serviceTypes is an array of integers

var resultsTemp = repository.Files.Where(f => !_serviceTypes.Except(f.Services.Select(s => s.ServiceTypeID)).Any());

edited Dec 6, 2017 at 15:17

answered Dec 6, 2017 at 14:49

grek40

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Comments

decPL · Accepted Answer · 2017-12-06 14:51:24Z

0

You're checking if a single element exists in both lists, which is probably not what you had in mind. Try to check if the intersection is equal to the smaller list (assuming it's _serviceTypes, as that's not evident from your code):

var resultsTemp = repository.Files
                            .Where(f => f.Services.Select(s => s.ServiceTypeID)
                            .Intersect(_serviceTypes)
                            .OrderBy(x => x)
                            .SequenceEqual(_serviceTypes.OrderBy(x => x));

answered Dec 6, 2017 at 14:51

decPL

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