I have 2 lists I am trying to compare.
List SelectedPersonCodes; is a just a list of strings (obviously)
List CurrentUserLocations; is a list of LocationId, LocationName pairs.
I need to see if any of the CurrentUserLocation locationIds have a match in the SelectedPersonCOdes list, which is made up of locationIds.
I have put together this:
public JsonResult VerifyDetailAccess(int id)
{
List<UserLocation> CurrentUserLocation = repo.GetUserLocations();
List<string> SelectedPersonLocations = repo.GetTrespassedSiteCodes(id);
bool IsAuth = false;
foreach (var current in CurrentUserLocation)
{
for(var s = 0; s < SelectedPersonLocations.Count(); s++)
{
if(current.LocationCode == SelectedPersonLocations[s])
{
IsAuth = true;
}
}
}
return Json(IsAuth, JsonRequestBehavior.AllowGet);
}
It always comes out false. The problem is the if statement, I am not getting the values in the SelectedPersonLocations. How do I expose those values so I can iterate against them?
I have also tried dual foreach:
foreach (var current in CurrentUserLocation)
{
foreach (var select in SelectedPersonLocations)
{
if(current.LocationCode == select)
{
IsAuth = true;
}
}
This exposes the value in select, but even if current.LocationCode and select are the same, it still skips setting the flag, so IsAuth stays false.
Related
I have a situation where I'm passing an array of data (it can be any number, not fixed) from front-end, which is received as list in my API. I need each of the record's primary key value in order to pass them in my controller again to do further task. But using out, I am not able to return multiple data, it only returns the final value after finishing the loop.
Code-
public bool Add(List<Model> model) //have tried using out, but not working as I want
{
Model obj = new Model();
bool saved = false;
int id = 0;
foreach (Model m in model)
{
var data = _repo.Get(x => x.Id == m.Id);
var isExist = _repo.AsQueryable().Count();
if (isExist <= 0)
{
maxId = 1;
}
else
{
maxId = _repo.AsQueryable().Max(x => x.Id) + 1;
}
obj.Id = maxId; //the maxId for each loop iteration needs to be passed as out to fulfill my situation
obj.Name= m.Name;
obj.Dept= m.Dept;
_repo.Add(obj);
isSaved = true;
}
return isSaved;
}
Is there any way to return the maxId after each iteration or all maxId all together to my controller?
To return all at once create a List and either make that the return type of the method:
public List<TypeYouWantToReturn> Add(...)
{
List<TypeYouWantToReturn> list = new List<TypeYouWantToReturn>();
//make a loop and add the results here: list.Add(something);
return list;
}
or make it an out parameter as you mentioned:
public bool Add(out List<TypeYouWantToReturn> list)
{
//make a loop and add the results here: list.Add(something);
return true;
}
or use yield return to return values one by one.
I have a ViewModel that contains different elements inside different tables that I tend to assign to it by query.
My problem is that I can't do this with IEnumerable (in GetAll() below), it keeps returning me null for RoomCode but for a single item (in GetDeviceId() below) then it works fine.
public IEnumerable<DeviceViewModel> GetAll()
{
var result = deviceRepository.GetAll().Select(x => x.ToViewModel<DeviceViewModel>());
for(int i = 0; i < result.Count(); i++)
{
int? deviceID = result.ElementAt(i).DeviceId;
result.ElementAt(i).RoomCode = deviceRepository.GetRoomCode(deviceID);
}
return result;
}
public DeviceViewModel GetDeviceID(int deviceID)
{
var result = new DeviceViewModel();
var device = deviceRepository.Find(deviceID);
if (device != null)
{
result = device.ToViewModel<DeviceViewModel>();
result.RoomCode = deviceRepository.GetRoomCode(deviceID);
}
else
{
throw new BaseException(ErrorMessages.DEVICE_LIST_EMPTY);
}
return result;
}
public string GetRoomCode(int? deviceID)
{
string roomCode;
var roomDevice = dbContext.Set<RoomDevice>().FirstOrDefault(x => x.DeviceId == deviceID && x.IsActive == true);
if (roomDevice != null)
{
var room = dbContext.Set<Room>().Find(roomDevice.RoomId);
roomCode = room.RoomCode;
}
else
{
roomCode = "";
}
return roomCode;
}
First, you need to materialize the query to a collection in local memory. Otherwise, the ElementAt(i) will query the db and give back some kind of temporary object each time it is used, discarding any change you do.
var result = deviceRepository.GetAll()
.Select(x => x.ToViewModel<DeviceViewModel>())
.ToList(); // this will materialize the query to a list in memory
// Now modifications of elements in the result IEnumerable will be persisted.
You can then go on with the rest of the code.
Second (and probably optional), I also recommend for clarity to use foreach to enumerate the elements. That's the C# idiomatic way to loop through an IEnumerable:
foreach (var element in result)
{
int? deviceID = element.DeviceId;
element.RoomCode = deviceRepository.GetRoomCode(deviceID);
}
I've got a problem with removing duplicates at runtime from my list of object.
I would like to remove duplicates from my list of object and then set counter=counter+1 of base object.
public class MyObject
{
MyObject(string name)
{
this.counter = 0;
this.name = name;
}
public string name;
public int counter;
}
List<MyObject> objects_list = new List<MyObject>();
objects_list.Add(new MyObject("john"));
objects_list.Add(new MyObject("anna"));
objects_list.Add(new MyObject("john"));
foreach (MyObject my_object in objects_list)
{
foreach (MyObject my_second_object in objects_list)
{
if (my_object.name == my_second_object.name)
{
my_object.counter = my_object.counter + 1;
objects_list.remove(my_second_object);
}
}
}
It return an error, because objects_list is modified at runtime. How can I get this working?
With a help of Linq GroupBy we can combine duplicates in a single group and process it (i.e. return an item which represents all the duplicates):
List<MyObject> objects_list = ...
objects_list = objects_list
.GroupBy(item => item.name)
.Select(group => { // given a group of duplicates we
var item = group.First(); // - take the 1st item
item.counter = group.Sum(g => g.counter); // - update its counter
return item; // - and return it instead of group
})
.ToList();
The other answer seem to be correct, though I think it will do scan of the whole list twice, depending on your requirement this might or might not be good enough. Here is how you can do it in one go:
var dictionary = new Dictionary<string, MyObject>();
foreach(var obj in objects_list)
{
if(!dictionary.ContainsKey(obj.name)
{
dictionary[obj.name] = obj;
obj.counter++;
}
else
{
dictionary[obj.name].counter++;
}
}
Then dictionary.Values will contain your collection
I have a list of items in a list. From that list I need to take the first 1000 items and need to submit the package and then again I need to take another 1000 and need to submit a package. If the list is not having 1000 I need to submit the package with all the items. for that I wrote the following code which is returning an error as collection modified.
List<SyncQueue> tempMassiveSyncQueue=massiveSyncQueue;
while (tempMassiveSyncQueue.Count != 0)
{
int MassivePackageFileCount =Convert.ToInt32(ConfigurationManager.AppSettings["MassivePackageFileLimit"]);
massiveSyncQueues = tempMassiveSyncQueue;
List<SyncQueue> tempMassivePackageSyncQueue=new List<SyncQueue>();
if (massiveSyncQueues.Count > 1000
{
var massivePackageSyncQueue = (massiveSyncQueues.Take(1000)).ToList<SyncQueue>();
tempMassivePackageSyncQueue = massivePackageSyncQueue;
SubmitPackage(massivePackageSyncQueue);
}
if (tempMassivePackageSyncQueue.Count != 0)
{
foreach (var massivesynq in tempMassiveSyncQueue)
{
foreach (var deleteId in tempMassivePackageSyncQueue.Where(id => id.SyncQueueId == massivesynq.SyncQueueId))
{
tempMassiveSyncQueue.Remove(massivesynq);
}
}
}
else
{
SubmitPackage(massiveSyncQueues);
}
massiveSyncQueues = null;
}
Can any one help on this?
Incorporate Skip into your logic
int loopCount = 0;
While(true)
{
var ListToProcess = massiveSyncQueue.Skip(loopCount*1000).Take(1000);
SubmitPackage(ListToProcess);
if(ListToProcess.Count < 1000) // We know there are no more in the list massive list.
{
break;
}
loopCnt++;
}
Your problem is that you are adjusting the collection on which the bounds of the foreach construct are set.
Try using ToList() on the collection you are looping through, as this creates a new List in memory:
foreach (var massivesynq in tempMassiveSyncQueue.ToList())
{
foreach (var deleteId in tempMassivePackageSyncQueue.Where(id => id.SyncQueueId == massivesynq.SyncQueueId).ToList())
{
tempMassiveSyncQueue.Remove(massivesynq);
}
}
In line 1 you set tempMassiveSyncQueue = massiveSyncQueue, yet within the while loop you set massiveSyncQueue = tempMassiveSync.
The collection modified error usually occurs when you modify the collection you are looping through. Which is why you need to first create a copy of the collection which is INDEPENDANT to the original collection and loop through that.
Before the while loop you need to add all items in massiveSyncQueue to tempMassiveSyncQueue. You then need to loop through the temp list with your code. In the second loop, you are removing items from the list you are looping through. I assume you meant to remove the items from massiveSyncQueue and not the temp list.
Try the following:
List<SyncQueue> tempMassiveSyncQueue = new List<SyncQueue>();
foreach(var item in massiveSyncQueue)
{
tempMassiveSyncQueue.Add(item);
}
while (tempMassiveSyncQueue.Count != 0)
{
int MassivePackageFileCount = Convert.ToInt32(ConfigurationManager.AppSettings["MassivePackageFileLimit"]);
List<SyncQueue> tempMassivePackageSyncQueue=new List<SyncQueue>();
if (massiveSyncQueues.Count > 1000
{
var massivePackageSyncQueue = (massiveSyncQueues.Take(1000)).ToList<SyncQueue>();
tempMassivePackageSyncQueue = massivePackageSyncQueue;
SubmitPackage(massivePackageSyncQueue);
}
if (tempMassivePackageSyncQueue.Count != 0)
{
foreach (var massivesynq in massiveSyncQueue)
{
foreach (var deleteId in tempMassivePackageSyncQueue.Where(id => id.SyncQueueId == massivesynq.SyncQueueId))
{
massiveSyncQueue.Remove(massivesynq);
}
}
}
else
{
SubmitPackage(massiveSyncQueues);
}
massiveSyncQueues = null;
}
Try this
int count=1;
while(tempMassivePackageSyncQueue.Count>1000)
{
var massivePackageSyncQueue = (massiveSyncQueues.skip(count*1000).Take(1000)).ToList<SyncQueue>();
tempMassivePackageSyncQueue = massivePackageSyncQueue;
SubmitPackage(massivePackageSyncQueue);
count++;
}
var massivePackageSyncQueue = (massiveSyncQueues.skip(count*1000).Take()).ToList<SyncQueue>();
tempMassivePackageSyncQueue = massivePackageSyncQueue;
SubmitPackage(massivePackageSyncQueue);
I have a file that contains a list of delimited sequence numbers as a record key. I need to fill in the missing sequence. So if I have
8
8.2
8.3.4.1
I need to add
8.1
8.3
8.3.1
8.3.2
8.3.3
8.3.4
I have come up with a few algorithms but they're all horribly complex and have too many cases. Is there an easy way to do this or do I have to plod through? I'm using c# but Java would do.
Not sure if my solution is easy to understand, but let's try. The idea is that we recursively insert missing sequences between existing ones.
First, you need to parse your file to create a List of items representing existing sequence. Every item should have reference to the next one (linked list idea).
public class Item
{
public int Value { get; set; }
public Item SubItem { get; set; }
public Item NextItem { get; set; }
public Item(int value, Item subItem)
{
Value = value;
SubItem = subItem;
}
public Item CreatePreviousItem()
{
if (SubItem == null)
{
return Value == 1 ? null : new Item(Value - 1, null);
}
return new Item(Value, SubItem.CreatePreviousItem());
}
public bool IsItemMissingPrior(Item item)
{
if (item == null)
{
return false;
}
return
item.Value - Value > 1
|| (SubItem == null && item.SubItem != null && item.SubItem.Value > 1) //edge case
|| (SubItem != null && SubItem.IsItemMissingPrior(item.SubItem));
}
public override string ToString()
{
return Value + (SubItem != null ? "." + SubItem : "");
}
}
Assuming that sequences are delimited by new line symbol, you can use the following Parse method.
private List<Item> Parse(string s)
{
var result = new List<Item>();
var numberLines = s.Split(new[] {Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries);
foreach (var numberLine in numberLines)
{
var numbers = numberLine.Split(new[] {'.'}).Reverse();
Item itemInstance = null;
foreach (var number in numbers)
{
itemInstance = new Item(Convert.ToInt32(number), itemInstance);
}
if (result.Count > 0)
{
result.Last().NextItem = itemInstance;
}
result.Add(itemInstance);
}
return result;
}
Here is a recursive method which inserts missing sequences between two existing ones
private void UpdateSequence(Item item)
{
if (item.IsItemMissingPrior(item.NextItem))
{
var inBetweenItem = item.NextItem.CreatePreviousItem();
inBetweenItem.NextItem = item.NextItem;
item.NextItem = inBetweenItem;
UpdateSequence(item);
}
}
And finally the use case:
var inputItems = Parse(inputString);
foreach (var item in inputItems)
{
UpdateSequence(item);
}
That's it. To see the result, you just need to get the first item from the list and keep moving forward using NextItem property. For example
var displayItem = inputItems.FirstOrDefault();
while (displayItem != null)
{
Console.WriteLine(displayItem.ToString());
displayItem = displayItem.NextItem;
}
Hope it helps.
One of the easy ways (though not optimal for some cases) will be maintaining a set of existing keys. For each key in your initial sequence you can add all the preceding keys to that set. This can be done in two loops: in inner loop you add a key to a set and decrease last number of a key by one while the number is more than zero, in outer loop you decrease the length of a key by one.
And then you just need to output the set in sorted order.