How to get sum in nested collection via LINQ - linq

class YearlyData
{
MonthlyData[] monthlyData = new MonthlyData[12];
}
class MonthlyData
{
int Salary;
}
Given I have a List<YearlyData>, how can I find total salary for a given month for the number of years.
Example for three years I need total salary given for 1st month & subsequent months.

If you want the sum of all the Salaries for April:
List<YearlyData> l;
l.Sum(yd => yd.monthlyData[3].Salary);
If I misread your question, and you really want all the salaries for April & subsequent months (in the year)
l.Sum(yd => yd.monthlyData.Skip(3).Sum());

Something like this:
list.SelectMany(x => x.monthlyData
.Select((m, i) => new {month = i+1,
data = m.Salary}
))
.GroupBy(x => x.month)
.Select(x => new {month = x.Key,
total = x.Sum(m => m.data)});
This will give you a list with twelve entries, one for each month along with the total amount of that month.

Related

linq avg on grouped counts

Please consider this simple class
public class SEANCE
{
int ID_SEANCE {get;set;}
DateTime SEA_DATE {get;set;}
}
It's for a fitness management app, the SEANCE class is the session table for the members.
Here's my starting query to show the number of the sessions grouped by day Hour
var lst = ctx.SEANCES
.GroupBy(o => o.SEA_DATE.Hour)
.Select(g => new ChartData()
{
DT = new DateTime(2017, 01, 01, g.Key, 0, 0),
VALUE = g.Count()
});
return lst.OrderBy(a => a.DT).ToList();
as you can see, it returns the total number of sessions grouped by hour.
What I want instead is the average number of sessions by day and grouped by hour, and that's where I am a little lost :p
here what i mean
for example at 18, 1500 is corresponding to the total number of sessions at that time.
what i want instead is the average number by day
hope it make sense now :)
ctx.SEANCES.Count() / lst.Count(), but that seems like database source so better to use the result:
var groups = ctx.SEANCES
.GroupBy(s => s.SEA_DATE.Hour)
.OrderBy(g => g.Key)
.Select(g => new ChartData()
{
DT = g.First().SEA_DATE,
VALUE = g.Count()
})
.ToList();
var averageByHour = groups.Average(c => c.VALUE);
var averageByDay = groups.GroupBy(s => s.DT.Day).Average(g => g.Sum(c => c.VALUE));

How do I get a count of values by month in linq to sql?

I have a table of feedback scores, which essentially contains a date field and a "score" field (which may be "happy", "neutral" or "sad").
I want to return a query which gives me the count of each score by month, like this:
However, my query isn't grouping correctly - I'm basically getting three rows for each month (one row for "happy", one for "neutral" and one for "sad", like this:
How do I aggregate the data together?
My query at the moment is this:
var monthlyScore = from f in db.tl_feedbacks
group f by new { month = f.timestamp.Month, year = f.timestamp.Year, score = f.tl_feedback_score.score } into g
select new
{
dt = string.Format("{0}/{1}", g.Key.month, g.Key.year),
happyCount = g.Where(x => x.tl_feedback_score.score == "happy").Count(),
neutralCount = g.Where(x => x.tl_feedback_score.score == "neutral").Count(),
sadCount = g.Where(x => x.tl_feedback_score.score == "sad").Count(),
total = g.Count()
};
Remove , score = f.tl_feedback_score.score from your grouping.

LINQ query to return first item in an ordered grouping

Grouping is an area of LINQ that I haven't quite managed to get my head around yet. I have the following code:
var subTrips = tbTripData
.Where(t => selectedVehicleIds.Contains(t.VehicleID))
.Join(tbSubTripData,
t => t.TripID,
s => s.TripID,
(t, s) => new { t = t, s = s })
.Select(r =>
new SubTrip
{
VehicleID = r.t.VehicleID,
TripID = r.t.TripID,
Sequence = r.s.Sequence,
TripDistance = r.s.TripDistance,
Odometer = r.s.Odometer
})
.ToList();
I'm trying to figure out a LINQ query that will look at subTrips and for each VehicleID, find the first Odometer, i.e. the Odometer corresponding to the lowest TripID and Sequence values.
I've been poking at it for an hour but just can't figure it out. Can anyone offer some advice before I give up and write procedural code to do it?
UPDATE: To clarify, Sequence is the sequential number of each subtrip within a trip. So what I'm looking for is the Odometer from the first subtrip for each vehicle when the subtrips within each grouped VehicleID are ordered by TripID then by Sequence.
I'm not 100% what you're looking for. But this might get you started in the right direction.
var groupedList = (from s in subTrips
group s by s.VehicleID
into grp
select new
{
VehicleID = grp.Key,
Odometer = grp.OrderBy(ex => ex.TripID).Select(ex => ex.Odometer).First(),
TripID = grp.Min(ex => ex.TripID)
}
).ToList();
This will return the VehicleID, the Odometer corresponding to the lowest TripID, and the lowest TripID.

multiple group by using linq

I need return just 2 lines in my query. One line with a string Today and a number of cases closed today, on my second line I need a string Last Week and a number of cases closed on the last week.
How I group with a range date?
Sum Name
----------- ----------
12 Today
33 Last Weeb
How about this:
var caseCounts = Cases
.Where(c => c.Date == today || (c.Date >= startOfLastWeek && c.Date <= endOfLastWeek))
.GroupBy(c => c.Date == today ? "Today" : "Last Week")
.Select(g => new {
Name = g.Key, Sum = g.Count()
});
You would need to define the 3 dates (today, startOfLastWeek, endOfLastWeek) before hand, but it gives you the results you are after.
GROUP BY YEARWEEK(date) should work. Depending on your dbms, you might be able to use another function, or program your own.
http://www.tutorialspoint.com/sql/sql-date-functions.htm#function_yearweek

entity framework grouping by datetime

Every 5 minutes a row in a sql server table is added. The fields are:
DateTime timeMark,Int total.
Using entity framework I want to populate a new list covering a whole week of five minute values using an average of the totals from the last three months.
How would I accomplish this with Entity Framework?
Assuming your log is really exact on the "five mintues", and that I understood well
, you want a list with 7 day * 24 hours * (60/5) minutes, so 2016 results ?
//define a startDate
var beginningDate = <the date 3 month ago to start with>;
//get the endDate
var endDate = beginningDate.AddMonths(3);
var list = myTable.Where(m => m.TimeMark >= beginningDate && m.TimeMark <=endDate)
//group by dayofWeek, hour and minute will give you data for each distinct day of week, hour and minutes
.GroupBy(m => new {
dayofWeek = SqlFunctions.DatePart("weekday", m.TimeMark),
hour = SqlFunction.DatePart("hour", m.TimeMark),
minute = SqlFunctions.DatePart("minute", m.TimeMark)
})
.Select(g => new {
g.Key.dayofWeek,
g.Key.hour,
g.Key.minute,
total = g.Average(x => x.Total)
});

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