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Except on Lists in c#

I count months and years from a given date to the present date
and from this list I have to subtract the months that were returned to me in the sql (linq) query.
I try to use "Except" on the results, but gives me an error in the picture below
var list = _ecpContext.Akceptacje_UnionAll_V
.Where(f => f.ADLogin == user)
.Select(f => new
{
Miesiac= f.Miesiac, //month
Rok= f.Rok // year
})
.ToList();
//-------------------------------------------------------------------
DateTime employmentDate = _ecpContext.Ustawienia.FirstOrDefault(x => x.UstLogin == user).EmploymentDate;
int employmentYear = employmentDate.Year;
int employmentMonth = employmentDate.Month;
DateTime now = DateTime.Now;
int currentYear = now.Year;
int currentMonth = now.Month;
var newList = Array.Empty<object>().Select(x => new { Month = 1, Year = 1 }).ToList();
for (var i = employmentYear; i <= currentYear; i++)
{
for (var x = employmentMonth; x <= currentMonth; x++)
{
newList.Add(new { Month = x, Year = i });
}
}
//-------------------------------------------------------------------
// i try
IEnumerable<DatesOfShortages> listMissingDates = list.Except(newList);
public class DatesOfShortages
{
public int Year { get; set; }
public int Month { get; set; }
}
new error

The Except method is a method which produces the set difference of two sequences so you need to invoke it.
IEnumerable<DatesOfShortages> listMissingDates = newList.Except(list);

You can't have one list A full of anonymous types, and another list B full of Tuples, and run a.Except(b) on them
Make a list of anonymous types instead of tuples:
var newList = Array.Empty<object>().Select(x => new { Month = 1, Year = 1 }).ToList();
for (var i = employmentYear; i <= currentYear; i++)
{
for (var x = employmentMonth; x <= currentMonth; x++)
{
newList.Add(new{ Month = x, Year = i});
}
}
For newList I suppose something like new [] { list.ElementAtOrDefault(-1) }.ToList(); would work too.. Whatever trick you feel like pulling to get a list of ATs!

GROUPBY and SUM on List items using LINQ

I have a List of type DailySummary
public class DailySummary
{
public string AffiliateID { get; set; }
public string TotalCalls { get; set; }
public string Date{ get; set; }
}
with following sample data:
List<DailySummary> DealerTFNDatesTable = new List<DailySummary>();
DealerTFNDatesTable.Add(new DailySummary() { AffiliateID="0", Date = "12/12/2016", TotalCalls = "10"});
DealerTFNDatesTable.Add(new DailySummary() { AffiliateID="0", Date = "12/13/2016", TotalCalls = "74"});
DealerTFNDatesTable.Add(new DailySummary() { AffiliateID="1", Date = "12/22/2016", TotalCalls = "63"});
DealerTFNDatesTable.Add(new DailySummary() { AffiliateID="0", Date = "12/12/2016", TotalCalls = "58"});
Now I want to retrieve Date and TotalCalls grouped by AffiliateID and assign in another list.
for(int i =0; i < DealerTFNDatesTable.Count; i++)
{
List<NewList> newList = new List<NewList>();
newList.Date = //Assign Dintinct dates WHERE AffiliateId = 0
newList.AffiliateID = //AffiliateID=0
newList.TotalCalls= //TotalCalls SUM GROUPBY DATE and AffiliateID = 0
//For Date '12/12/2016' it will be 68, For '12/13/2016' it will be 74 and so on
}
I'm sorry, I'm new to LINQ. Can someone help me or share resources where I can get a hint to achieve this?

This should work for grouping by AffilateID and Date and then getting the sum (though it's weird to store a number as a string for something like this, but whatever floats your boat).
var results = DealerTFNDatesTable
.GroupBy(x => new { x.AffiliateID, x.Date })
.Select(x => new DailySummary {
AffiliateID = x.First().AffiliateID,
Date = x.First().Date,
TotalCalls = x.Sum(y => Convert.ToInt32(y.TotalCalls)).ToString()
});
If you now look at the result, for example with this code, you get exactly the values you wanted:
foreach (var x in results) {
Console.WriteLine($"id = {x.AffiliateID}, date = {x.Date}, totalCalls = {x.TotalCalls}");
}
> id = 0, date = 12/12/2016, totalCalls = 68
> id = 0, date = 12/13/2016, totalCalls = 74
> id = 1, date = 12/22/2016, totalCalls = 63

First off,
Since DealerTFNDatesTable is a variable, you should use camel case. Thus it is dealerTFNDatesTable
Then to complete #andy his answer, as you also want to do a select. You can select it as follows:
var newVariable = from item in dealerTFNDatesTable
group item by new
{
item.Date,
item.AffiliateID,
}
into g
select new
{
Date = g.Key.Date,
Id = g.Key.AffiliateID,
Total = g.Sum(a => a.TotalCalls)
};
This will give you an IEnumerable, of which you can put the relevant parts in a list by doing var otherList = new List<object>(newVariable
.Where(a => a.Total > 0)); or simply add .ToList() after the select if you want the collection as-is.
Note that this is simply another notation than LINQ, the result is the same.

var results = DealerTFNDatesTable.GroupBy(T => new { T.AffiliateID })
Link

foreach loop data index as the key

I have been trying to make for each loop with the index as the key
this case i want to made a logic if the input user is match with index and i will show foreach all of the data which has index as the key
I made two class like this
class DataContainer
{
public DataContainer()
{
}
public int index { get; set; }
public List<DataValue> DataValue { get; set; }
}
class DataValue
{
public DataValue()
{
IntegerValues = new List<int>();
}
public string name { get; set; }
public List<int> IntegerValues { get; set; }
}
after that i try to make list of datacontainer like this
List<DataContainer> harakatSininilMabsutoh = new List<DataContainer>(){
new DataContainer{index = 2015 , DataValue = new List<DataValue>()
{
new DataValue{name = "first",IntegerValues = {9,55,18,11}},
new DataValue{name = "second" ,IntegerValues = {5,54,18,11}},
new DataValue{name = "third" ,IntegerValues = {40,26,14,11}},
new DataValue{name = "four" ,IntegerValues = {22,0,5,10}},
new DataValue{name = "fifth" ,IntegerValues = {46,44,17,0}},
}
},
new DataContainer{index = 2013 , DataValue = new List<DataValue>()
{
new DataValue{name = "first",IntegerValues = {26,49,8,11}},
new DataValue{name = "second" ,IntegerValues = {19,42,8,11}},
new DataValue{name = "third" ,IntegerValues = {55,3,12,11}},
new DataValue{name = "fourth" ,IntegerValues = {27,4,23,8}},
new DataValue{name = "fifth" ,IntegerValues = {43,22,7,1}},
}
},
new DataContainer{index = 2001, DataValue = new List<DataValue>()
{
new DataValue{name = "first",IntegerValues = {35,44,27,10}},
new DataValue{name = "second" ,IntegerValues = {24,41,27,10}},
new DataValue{name = "third" ,IntegerValues = {36,30,26,10}},
new DataValue{name = "fourth" ,IntegerValues = {59,24,8,6}},
new DataValue{name = "fifth" ,IntegerValues = {29,27,26,1}},
}
}
};
and then i made a logic like this
int years = (this is user input);
if(years == 2015)
{
///How to for each this which has index 2015
}
else if (years = 2013)
{
//how to foreach this which has index 2013
}
else if (years = 2001)
{
//how to foreach this which has index 2001

The simplest is by using LINQ FirstOrDefault like this
int userinput = 2015;
DataContainer requested = harakatSininilMabsutoh.FirstOrDefault(x => x.index == userinput);
if (requested == null) //FirstOrDefault of a class will return null if not found
return;
foreach (DataValue val in requested.DataValue)
Console.WriteLine(val.name + ": " + string.Join(", ", val.IntegerValues));
Edit 2:
If you only need all the integers, without name, without anything else, then you could either do this to get the List<List<int>>:
int userinput = 2015;
List<List<int>> intValuesOnly = harakatSininilMabsutoh
.FirstOrDefault(x => x.index == userinput)
.DataValue
.Select(y => y.IntegerValues)
.ToList();
//Do whatever you want with intValuesOnly. This is everything that you have in a list of lists
or do this to get List<int> (flattened):
int userinput = 2015;
List<int> intValuesOnly = harakatSininilMabsutoh
.FirstOrDefault(x => x.index == userinput)
.DataValue
.SelectMany(y => y.IntegerValues)
.ToList();
//Do whatever you want with intValuesOnly. This is everything that you have in single list
As FirstOrDefault may return null if the userinput is not found, note that, if you are not using C#6, you may want to consider two steps LINQ:
int userinput = 2015;
DataContainer requested = harakatSininilMabsutoh.FirstOrDefault(x => x.index == userinput);
if (requested == null) //FirstOrDefault of a class will return null if not found
return;
List<List<int>> intValuesOnly = requested
.Select(y => y.IntegerValues)
.ToList();
//Do whatever you want with intValuesOnly. This is everything that you have in a list of lists

Firstly, note that in this line you have tried to use a type name as a property name:
public List<DataValue> DataValue { get; set; }
I've renamed this property to 'DataValues' as shown:
public List<DataValue> DataValues { get; set; }
You have a list ('harakatSininilMabsutoh'), each element of which is a DataContainer. Each DataContainer in the list has two properties: an index and a list of 'DataValues' (NB renamed from 'DataValue' in your post).
The looping logic you want will therefore be something like this:
var matchingYears = harakatSininilMabsutoh.Where(h => h.index == years);
foreach (var dataContainer in matchingYears)
{
foreach (var item in dataContainer.DataValues)
{
// Action required on each DataValue:
Debug.Print(item.name + " " + string.Join(",", item.IntegerValues));
}
}
You'll need to add the following 'using' statement to your class, since 'Where' is a LINQ extension method:
using System.Linq;
If you know that there will be exactly one matching year, you could add First() and remove the outer foreach loop. If you know there will be at most one matching year (but there could be zero), you can still remove the outer foreach loop but you should use FirstOrDefault() instead and test for null.

Entity Framework query improved

I'm trying to make an android synchronization between client and ASP.NET MVC server. The logic is simple, my next method receives a data dictionary, where key = idGroup and value = LastMessageIdKnown, in the end I should get the next messages for each group what Id is higher than the LastMessageIdKnown (the value of my dictionary).
Right now I am iterating the map, for each key I do a query to my SQL database but this is inefficient, if I got N keys you can imagine what implying.
This is my current method
public Dictionary<int, List<Messages>> SynchronizedChatMessages(Dictionary<int, int> data)
{
Dictionary<int, List<Messages>> result = new Dictionary<int, List<Messages>>();
foreach(int item in data.Keys){
var idMessage= data[item];
var listMessages= _context.Messages.Where(x => x.Grupo_ID == item && x.ID > idMessage).ToList();
result.Add(item,listMessages);
}
return result;
}
How can I improve this query to get all what I need in an only and optimal way?
Thank you.

Here's an attempt that uses Predicates to make it so that there is only one Where against the whole collection of messages.
Note that I mocked this up without a database, so I am passing a List into the SynchronizedChatMessages function, whereas you have the context available.
What remains to be proven is that this way of doing things only generates one query to the database (since I did it in objects only). The whole program is further, below, but first, just the function showing use of predicates to achieve firing the Where only once.
public static Dictionary<int, List<Message>> SynchronizedChatMessages(List<Message> messages, Dictionary<int, int> data)
{
List<Predicate<Message>> predList = new List<Predicate<Message>>();
//Built of list of indivIdual predicates
foreach (var x in data)
{
var IdMessage = x.Key;
var lastMessageId = x.Value;
Predicate<Message> pred = m => m.IdGroup.Id == IdMessage && m.Id > lastMessageId;
predList.Add(pred);
}
//compose the predicates
Predicate<Message> compositePredicate = m =>
{
bool ret = false;
foreach (var pred in predList)
{
//If any of the predicates is true, the composite predicate is true (OR)
if (pred.Invoke(m) == true) { ret = true; break; }
}
return ret;
};
//do the query
var messagesFound = messages.Where(m => compositePredicate.Invoke(m)).ToList();
//get the individual distinct IdGroupIds
var IdGroupIds = messagesFound.Select(x => x.IdGroup.Id).ToList().Distinct().ToList();
//Create dictionary to return
Dictionary<int, List<Message>> result = new Dictionary<int, List<Message>>();
foreach (int i in IdGroupIds)
{
result.Add(i, messagesFound.Where(m => m.IdGroup.Id == i).ToList());
}
return result;
}
Here is the whole thing:
using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsoleApplication20
{
public class Program
{
public class Message
{
public int Id { get; set; }
public IdGroup IdGroup { get; set; }
}
public class IdGroup
{
public int Id { get; set; }
public List<Message> Messages { get; set; }
}
public static Dictionary<int, List<Message>> SynchronizedChatMessages(List<Message> messages, Dictionary<int, int> data)
{
List<Predicate<Message>> predList = new List<Predicate<Message>>();
//Built of list of indivIdual predicates
foreach (var x in data)
{
var IdMessage = x.Key;
var lastMessageId = x.Value;
Predicate<Message> pred = m => m.IdGroup.Id == IdMessage && m.Id > lastMessageId;
predList.Add(pred);
}
//compose the predicates
Predicate<Message> compositePredicate = m =>
{
bool ret = false;
foreach (var pred in predList)
{
//If any of the predicates is true, the composite predicate is true (OR)
if (pred.Invoke(m) == true) { ret = true; break; }
}
return ret;
};
//do the query
var messagesFound = messages.Where(m => compositePredicate.Invoke(m)).ToList();
//get the individual distinct IdGroupIds
var IdGroupIds = messagesFound.Select(x => x.IdGroup.Id).ToList().Distinct().ToList();
//Create dictionary to return
Dictionary<int, List<Message>> result = new Dictionary<int, List<Message>>();
foreach (int i in IdGroupIds)
{
result.Add(i, messagesFound.Where(m => m.IdGroup.Id == i).ToList());
}
return result;
}
public static void Main(string[] args)
{
var item1 = new IdGroup { Id = 2, Messages = new List<Message>() };
var item2 = new IdGroup { Id = 45, Messages = new List<Message>() };
var item3 = new IdGroup { Id = 36, Messages = new List<Message>() };
var item4 = new IdGroup { Id = 8, Messages = new List<Message>() };
var message1 = new Message { Id = 3, IdGroup = item1 };
var message2 = new Message { Id = 7, IdGroup = item1 };
var message3 = new Message { Id = 9, IdGroup = item1 };
item1.Messages.Add(message1);
item1.Messages.Add(message2);
item1.Messages.Add(message3);
var message4 = new Message { Id = 4, IdGroup = item2 };
var message5 = new Message { Id = 10, IdGroup = item2 };
var message6 = new Message { Id = 76, IdGroup = item2 };
item2.Messages.Add(message4);
item2.Messages.Add(message5);
item2.Messages.Add(message6);
var message7 = new Message { Id = 6, IdGroup = item3 };
var message8 = new Message { Id = 32, IdGroup = item3 };
item3.Messages.Add(message7);
item3.Messages.Add(message8);
var message9 = new Message { Id = 11, IdGroup = item4 };
var message10 = new Message { Id = 16, IdGroup = item4 };
var message11 = new Message { Id = 19, IdGroup = item4 };
var message12 = new Message { Id = 77, IdGroup = item4 };
item4.Messages.Add(message9);
item4.Messages.Add(message10);
item4.Messages.Add(message11);
item4.Messages.Add(message12);
List<IdGroup> items = new List<IdGroup> { item1, item2, item3, item4 };
List<Message> messages = new List<Message> { message1, message2, message3, message4, message5, message6,message7, message8, message9, message10, message11, message12};
Dictionary<int, int> lastMessagesPerItem = new Dictionary<int, int> { { 2, 3 }, { 45, 10 }, { 36, 6 }, { 8, 11 } };
var result = SynchronizedChatMessages(messages, lastMessagesPerItem);
var discard = Console.ReadKey();
}
}
}

Well it would be nice if this would work, but I doubt it that can be translated to a SQL statement in one go:
var toInsert =
from msg in _context.Messages
group msg by msg.Grupo_ID into g
where data.Keys.Contains(g.Key)
select new {
Item = g.Key,
Messages = g.Where(x => x.ID > data[g.Key])
};
I don't think the second Where clause x => x.ID > data[g.Key] can be translated.
So you may need to do this in two passes, like this:
// This is a single SQL query.
var groups =
from msg in _context.Messages
group msg by msg.Grupo_ID into g
where data.Keys.Contains(g.Key)
select new {
Item = g.Key,
// ordering helps us when we do the in-memory part.
Messages = g.OrderByDescending(x => x.ID).ToList()
};
// This iterates the result set in memory
foreach (var g in groups)
result.Add(
g.Item,
// input is ordered, we stop when an item is <= data[g.Item].
g.Messages.TakeWhile(m => m.ID > data[g.Item]).ToList())

query to get all action during for each hour

i want to run and print a query that shows the number of orders per each hour in a day(24).
should look like:
hour-1:00, number of orders-5
hour-2:00, number of orders-45
hour-3:00, number of orders-25
hour-4:00, number of orders-3
hour-5:00, number of orders-43
and so on...
i try:
public void ShowBestHours()
{
using (NorthwindDataContext db = new NorthwindDataContext())
{
var query =
from z in db.Orders
select new Stime
{
HourTime = db.Orders.GroupBy(x => x.OrderDate.Value.Hour).Count(),
};
foreach (var item in query)
{
Console.WriteLine("Hour : {0},Order(s) Number : {1}", item.HourTime, item.Count);
}
}
}
public class Stime
{
public int HourTime { get; set; }
public int Count { get; set; }
}

You need to change your query to
var query =
from z in db.Orders
group z by z.OrderDate.Value.Hour into g
select new Stime{ HourTime = g.Key, Count=g.Count () };
or alternatively
var query = db,Orders.GroupBy (o => o.OrderDate.Value.Hour).Select (
g => new Stime{ HourTime=g.Key, Count=g.Count () });
In my copy of Northwind all of the OrderDate values are dates only so the result is just
HourTime = 0, Count = 830.
I'm assuming you're just experimenting with grouping. Try grouping by day of week like this
var query = db.Orders.GroupBy (o => o.OrderDate.Value.DayOfWeek).Select (
g => new { DayOfWeek=g.Key, Count=g.Count () });
which gives a more useful result.

You aren't setting Stime.Count anywhere in your query and you aren't grouping by hour correctly. I haven't seen your exact setup of course, but I think the following should work for you.
var query =
from z in db.Orders
group z by z.OrderDate.Value.Hour into g
select new Stime() { HourTime = g.Key, Count = g.Count() };
foreach (var item in query)
{
Console.WriteLine("Hour : {0},Order(s) Number : {1}", item.HourTime, item.Count);
}

Try this:
public void ShowBestHours()
{
using (NorthwindDataContext db = new NorthwindDataContext())
{
var query = db.Orders.GroupBy(x => x.OrderDate.Value.Hour).OrderByDescending(x => x.Count()).Select(x => new Stime { HourTime = x.Key, Count = x.Count() });
foreach (var item in query)
{
Console.WriteLine("Hour : {0},Order(s) Number : {1}", item.HourTime, item.Count);
}
}
}