Develop Reference

Count occurrences of an event by date with C#

I am facing an issue with counting the number of occurrences by date in C#. Should I use Linq to filter it? Please advise. Thank you.
Date
Player ID
1/1/2001
23
1/1/2001
29
1/1/2001
24
3/1/2001
22
3/1/2001
23
My preferred output should be
Date
No. Of Players
1/1/2001
3
2/1/2001
0
3/1/2001
2
This is my current code, how can I do it within the select:
var convertTable = dataPageTable.AsEnumerable();
Records = new List<List<ContentOutputModel>>(convertTable.Select(dr =>
{
var playerId = dr.GetColumn<long>("PlayerID").ToString();
var dateInt = dr.GetColumn<int>("Date").ToString();
var dateStr = dateInt.Substring(6, 2) + "/" + dateInt.Substring(4, 2) + "/" + dateInt.Substring(0, 4);
var output = new List<ContentOutputModel>(new ContentOutputModel[] {
new ContentOutputModel() { Text = dateStr },
new ContentOutputModel() { Text = playerId },
});
return output;
}));

Here's the cleanest that I could come up with:
List<Player> players = new List<Player>()
{
new Player() { Date = new DateTime(2021, 1, 1), ID = 23 },
new Player() { Date = new DateTime(2021, 1, 1), ID = 29 },
new Player() { Date = new DateTime(2021, 1, 1), ID = 24 },
new Player() { Date = new DateTime(2021, 1, 3), ID = 22 },
new Player() { Date = new DateTime(2021, 1, 3), ID = 23 }
};
var first = players.Min(p => p.Date);
var last = players.Max(p => p.Date);
var days = last.Subtract(first).Days + 1;
var lookup = players.ToLookup(p => p.Date);
var output =
from n in Enumerable.Range(0, days)
let Date = first.AddDays(n)
select new
{
Date,
Count = lookup[Date].Count(),
};
That gives me:

You can achieve by Group() via System.Linq.
Order players by Date and get startDate and endDate.
Generate an array with dates from startDate to endDate.
3.1 With group to count player(s) by Date.
3.2 Left join result from (2) with the result (3.1) to get Date and Count.
using System.Linq;
using System.Collections.Generic;
List<Player> players = new List<Player>
{
new Player{Date = new DateTime(2021, 1, 1), ID = 23},
new Player{Date = new DateTime(2021, 1, 1), ID = 29},
new Player{Date = new DateTime(2021, 1, 1), ID = 24},
new Player{Date = new DateTime(2021, 1, 3), ID = 22},
new Player{Date = new DateTime(2021, 1, 3), ID = 23}
};
var startDate = players.OrderBy(x => x.Date)
.First()
.Date;
var endDate = players.OrderBy(x => x.Date)
.Last()
.Date;
var dates = Enumerable.Range(0, 1 + endDate.Subtract(startDate).Days)
.Select(offset => startDate.AddDays(offset))
.ToArray();
var result = (from a in dates
join b in
(
from p in players
group p by p.Date into g
select new { Date = g.Key, Count = g.Count() }
) on a.Date equals b.Date into ab
from b in ab.DefaultIfEmpty()
select new { Date = a.Date, Count = b != null ? b.Count : 0 }
);
Sample program
Output
Date: 1/1/2021, Count: 3
Date: 2/1/2021, Count: 0
Date: 3/1/2021, Count: 2

You can use linq to do this as long as it can enumerate through a list or some other IEnumerable. Try this:
var playersSorted = yourlist.GroupBy(x => x.Date)
.Where(g => g.Any())
.Select(y => new {Date = y.Key, Count = y.Count()}).ToList();

var playersgroup = from e in players
group e by Date into g
select new { Date= g.Key, NoOfPlayers = g.Count() };

LINQ reusing Select statement with anonymous grouping types

I am trying to find a way to cut out repeated code in an application that center around LINQ select statements. Lets say we have existing table rows that need to be aggregated and grouped for different reporting requirements and all original data is just grouped by day and needs to be grouped by week / month and another property.
DataRow is an example object that needs to be grouped and converted into an object ReportTableRow (please note this is a much reduced object but the actual objects have far more properties and therefore become much more drawn out).
public class DataRow
{
public DateTime Date { get; set; }
public string AccountNumber { get; set; }
public string MachineNumber { get; set; }
public int TEST { get; set; }
}
public class ReportTableRow
{
public int WeekNumber { get; set; }
public int Month { get; set; }
public string AccountNumber{ get; set; }
public string MachineNumber { get; set; }
public int TEST { get; set; }
public string TEST_TRAFFICLIGHT { get; set; }
}
And we create a list of DataRows:
List<DataRow> reportTable = new List<DataRow>()
{
new DataRow()
{
Date = new DateTime(2021, 06, 14),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 2
},
new DataRow()
{
Date = new DateTime(2021, 06, 15),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 1
},
new DataRow()
{
Date = new DateTime(2021, 06, 15),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 6
},
new DataRow()
{
Date = new DateTime(2021, 06, 16),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 4
},
new DataRow()
{
Date = new DateTime(2021, 06, 17),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 2
},
new DataRow()
{
Date = new DateTime(2021, 06, 18),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 7
},
new DataRow()
{
Date = new DateTime(2021, 06, 19),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 2
},
new DataRow()
{
Date = new DateTime(2021, 06, 20),
AccountNumber = "11111111",
MachineNumber = "00AB2021",
TEST = 11
},
new DataRow()
{
Date = new DateTime(2021, 06, 14),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 2
},
new DataRow()
{
Date = new DateTime(2021, 06, 15),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 1
},
new DataRow()
{
Date = new DateTime(2021, 06, 15),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 6
},
new DataRow()
{
Date = new DateTime(2021, 06, 16),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 4
},
new DataRow()
{
Date = new DateTime(2021, 06, 17),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 2
},
new DataRow()
{
Date = new DateTime(2021, 06, 18),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 7
},
new DataRow()
{
Date = new DateTime(2021, 06, 19),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 2
},
new DataRow()
{
Date = new DateTime(2021, 06, 20),
AccountNumber = "22222222",
MachineNumber = "11BC2021",
TEST = 11
}
};
So if we either need the data grouped "BY WEEK" or "BY MONTH" then we need to actually return in the report the WeekNumber or Month number respectively and the grouping would look something like this where GetTrafficLight method returns a string value based on the value of the sum of TEST:
switch (aggregate.ToUpper())
{
case "BY WEEK":
reportTable = reportTable
.GroupBy(x => new { x.AccountNumber, WeekNumber = CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(x.Date, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday) })
.Select(x => new ReportTableRow
{
WeekNumber = x.Key.WeekNumber,
Month = x.Max(y => y.Date).Month,
MachineNumber = x.FirstOrDefault().MachineNumber,
TEST = x.Sum(y => y.TEST),
TEST_TRAFFICLIGHT = GetTrafficLight(x.Sum(y => y.TEST)
})
.ToList();
break;
case "BY MONTH":
reportTable = reportTable
.GroupBy(x => new { x.AccountNumber, x.Date.Month })
.Select(x => new ReportTableRow
{
WeekNumber = CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(x.Max(y => y.Date), CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday),
Month = x.Key.Month,
MachineNumber = x.FirstOrDefault().MachineNumber,
TEST = x.Sum(y => y.TEST),
TEST_TRAFFICLIGHT = GetTrafficLight(x.Sum(y => y.TEST)
})
.ToList();
break;
}
The question is, is there anyway to remove the "Select" code and pass it into either a method or object that would accept an anonymous grouping so that it can be reused multiple times. Changing the anonymous grouping to a compile time object that contains two properties means duplicates are then returned in the dataset, could be that finding a way to remove the duplicates in compile time grouped members might help to resolve?
Please note, the code has been created to pose this question.

This is optional, but the first thing I would do is put that "aggregate" into a boolean variable:
bool byWeek = aggregate.ToUpper() == "BY WEEK";
The next thing I would do is capture and tame that "GetWeekOfYear" logic:
int getFirstMonday (DateTime date) =>
CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(
date,
CalendarWeekRule.FirstFourDayWeek,
DayOfWeek.Monday
);
Doing these things makes it more feasible to put the conditional logic inside the GroupBy and Select methods, making it so that you don't have to do the whole thing twice:
List<ReportTableRow> results =
reportTable
.GroupBy(x => new {
x.AccountNumber,
TimeBin = byWeek ? getFirstMonday(x.Date): x.Date.Month
})
.Select(x => new ReportTableRow {
WeekNumber = byWeek ? x.Key.TimeBin : getFirstMonday(x.Max(y => y.Date)),
Month = byWeek ? x.Max(y => y.Date).Month : x.Key.TimeBin,
MachineNumber = x.FirstOrDefault().MachineNumber,
TEST = x.Sum(y => y.TEST),
TEST_TRAFFICLIGHT = GetTrafficLight(x.Sum(y => y.TEST))
})
.ToList();
I should note that your sample data makes it so that the results are the same regardless of 'aggregate' setting. But if you change it a bit, such as changing the days for some of the entries, you'll get different results in the aggregation. And at least for the changes I made my code repeats the behavior of your code when toggling 'aggregate'.

Complex linq join in EF6

There are two entities, for example, job and solution.
Each of them has a date field and a level field and a quantity field.
It is necessary to combine them so that they are grouped first by level, then by month, and at the same time, their quantity must be summed up.
I tried different options, but nothing comes out at all. The main problem is grouping by months and summing the numbers in the enclosed sheets.
That is, the output should be one sequence of summed numbers, grouped by level, and then by month.
For example:
var jobs = new List<Job>()
{
new Job { Level = 1, Date = new DateTime(2019, 1, 1), Quantity = 111 },
new Job { Level = 1, Date = new DateTime(2019, 1, 20), Quantity = 222 },
new Job { Level = 2, Date = new DateTime(2019, 2, 1), Quantity = 333 },
new Job { Level = 2, Date = new DateTime(2019, 2, 20), Quantity = 444 }
};
var solutions = new List<Solution>()
{
new Solution { Level = 1, Date = new DateTime(2019, 2, 1), Quantity = 555 },
new Solution { Level = 2, Date = new DateTime(2019, 2, 20), Quantity = 666 },
new Solution { Level = 1, Date = new DateTime(2019, 1, 1), Quantity = 777 },
new Solution { Level = 2, Date = new DateTime(2019, 1, 20), Quantity = 888 }
};
Output:
Level 1 -> 1 Jan 2019 -> 1110 (111 + 222 + 777)
Level 1 -> 1 Feb 2019 -> 555
Level 2 -> 1 Jan 2019 -> 888
Level 2 -> 1 Feb 2019 -> 1443 (333 + 444 + 666)
And so on. And yes, all this is in EF6.

Try following which uses Concat. I create a class for the merging. It can also be done anonymously.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication116
{
class Program
{
static void Main(string[] args)
{
var jobs = new List<Job>()
{
new Job { Level = 1, Date = new DateTime(2019, 1, 1), Quantity = 111 },
new Job { Level = 1, Date = new DateTime(2019, 1, 20), Quantity = 222 },
new Job { Level = 2, Date = new DateTime(2019, 2, 1), Quantity = 333 },
new Job { Level = 2, Date = new DateTime(2019, 2, 20), Quantity = 444 }
};
var solutions = new List<Solution>()
{
new Solution { Level = 1, Date = new DateTime(2019, 2, 1), Quantity = 555 },
new Solution { Level = 2, Date = new DateTime(2019, 2, 20), Quantity = 666 },
new Solution { Level = 1, Date = new DateTime(2019, 1, 1), Quantity = 777 },
new Solution { Level = 2, Date = new DateTime(2019, 1, 20), Quantity = 888 }
};
List<LevelDateQuantity> concat = jobs.Select(x => new LevelDateQuantity() { Date = x.Date, Level = x.Level, Quantity = x.Quantity})
.Concat( solutions.Select(x => new LevelDateQuantity() { Date = x.Date, Level = x.Level, Quantity = x.Quantity})).ToList();
List<LevelDateQuantity> results = concat.OrderBy(x => x.Level).ThenBy(x => x.Date)
.GroupBy(x => new { level = x.Level, date = new DateTime(x.Date.Year, x.Date.Month,1)})
.Select(x => new LevelDateQuantity() { Level = x.Key.level, Date = x.Key.date, Quantity = x.Sum(y => y.Quantity)})
.ToList();
}
}
public class LevelDateQuantity
{
public int Level { get; set; }
public DateTime Date { get; set; }
public int Quantity { get; set; }
}
public class Job : LevelDateQuantity
{
public int Level { get; set; }
public DateTime Date { get; set; }
public int Quantity { get; set; }
}
public class Solution : LevelDateQuantity
{
public int Level { get; set; }
public DateTime Date { get; set; }
public int Quantity { get; set; }
}
}

Oath, because we can not see your poco class structure we don't know if the two tables are seperate or has a one to many relation to a master table, so by the code you have provided I would do this ;
var jobs = new List<Job>()
{
new Job { Level = 1, Date = new DateTime(2019, 1, 1), Quantity = 111 },
new Job { Level = 1, Date = new DateTime(2019, 1, 20), Quantity = 222 },
new Job { Level = 2, Date = new DateTime(2019, 2, 1), Quantity = 333 },
new Job { Level = 2, Date = new DateTime(2019, 2, 20), Quantity = 444 }
};
var solutions = new List<Solution>()
{
new Solution { Level = 1, Date = new DateTime(2019, 2, 1), Quantity = 555 },
new Solution { Level = 2, Date = new DateTime(2019, 2, 20), Quantity = 666 },
new Solution { Level = 1, Date = new DateTime(2019, 1, 1), Quantity = 777 },
new Solution { Level = 2, Date = new DateTime(2019, 1, 20), Quantity = 888 }
};
foreach (var sol in solutions)
{
var jb = new Job();
jb.Level = sol.Level;
jb.Date = sol.Date ;
jb.Quantity= sol.Quantity;
jobs.Add(jb);
}
var result = Jobs.GroupBy(x=> new { x.Level, x.Date}).Select(x=> new
{
level = x.Key.Level,
date = x.Key.Date,
sumQ = x.Sum(y => y.Quantity )
});
I haven't tested the code and not wrote in in a compiler so there might be some typeerrors apart from that this should solve your problem.

Insert Data into middle of range

I have the following model
public class DailyRoutine
{
public int Id { get; set; }
public DateTime Date { get; set; }
public string Description { get; set; }
}
Scenario:
When is created at initial time with 5 records which means 5 entries are entered for each day. Take an example May 1 to May 5 of 2017. Description have any string.
User can add a new record in the middle so that the following records should be moved and changed to next days.
Expected Output:
Example, user can give a date and description in input and submit. If the input date is '5/3/2017' (May 3), the entry should be added after May 2 record and the existing May 3 record changed to May 4, May 4 to May 5 etc. So the out is like May 1 to May 6 and the given input is updated on May 3.
Please help me to this with out degrading performance

This approach will work:
List<DailyRoutine> d = new List<DailyRoutine>()
{
new DailyRoutine() { Date = new DateTime(2017, 7, 1)},
new DailyRoutine() { Date = new DateTime(2017, 7, 2)},
new DailyRoutine() { Date = new DateTime(2017, 7, 3)},
new DailyRoutine() { Date = new DateTime(2017, 7, 4)},
new DailyRoutine() { Date = new DateTime(2017, 7, 5)}
};
DailyRoutine newDr = new DailyRoutine() { Date = new DateTime(2017, 7, 2) };
DailyRoutine oldDr = d.Where(dr => dr.Date == newDr.Date).FirstOrDefault();
if (oldDr != null)
{
int idx = d.IndexOf(oldDr);
List<DailyRoutine> changeList = d.Where((dr, i) => i >= idx).ToList();
foreach (DailyRoutine i in changeList)
{
i.Date = i.Date.AddDays(1);
}
d.Insert((int)idx, newDr);
}
else
{
d.Add(newDr);
}

Get dates that contain all selected products

I have a calendar app where you select various combinations of products- a service goes out and gets the available dates based on the calendar date range. A date is only "Available" if ALL selected products are available on a particular date.
class SelectedProduct
{
public int ID { get; set; }
public int Qty { get; set; }
}
class AvailableInventory
{
public int ID { get; set; }
public DateTime Date { get; set; }
}
// List of selected products from user
List<SelectedProduct> SelectedProducts;
// populated from service with all dates for all products
List<AvailableInventory> AvailableInventory;
I want to be able to say get list of Available Inventory for each date that contains inventory for all ID's in selected products.
This is (non-working) pusdo code of a possible solution, I just don't know linq well enough to get it right
var results = List<AvailableInventory>();
foreach (var group in AvailableInventory.GroupBy(x => x.Date))
{
if (group.Contains(ALL ID's in SelectedProducts)
{
results.AddRange(group);
}
}

This groups inventory by date (ignoring the date portion), then selects only those groups that contain all selected product IDs, and finally selects all available inventory for the matching groups.
var results =
AvailableInventory.GroupBy(i => i.Date.Date)
.Where(g => !SelectedProducts.Select(p => p.ID)
.Except(g.Select(i => i.ID))
.Any())
.SelectMany(g => g);
The result is a collection of AvailableInventory.

You can group by the date, then filter out groups that don't have all the SelectedProducts.
// List of selected products from user
List<SelectedProduct> SelectedProducts = new List<SelectedProduct> {
new SelectedProduct { ID = 1, Qty = 1 },
new SelectedProduct { ID = 2, Qty = 2 },
};
// populated from service with all dates for all products
List<AvailableInventory> AvailableInventory = new List<AvailableInventory> {
new AvailableInventory { ID = 1, Date = new DateTime(2014, 04, 11) },
new AvailableInventory { ID = 2, Date = new DateTime(2014, 04, 11) },
new AvailableInventory { ID = 1, Date = new DateTime(2014, 04, 12) },
new AvailableInventory { ID = 2, Date = new DateTime(2014, 04, 13) },
new AvailableInventory { ID = 1, Date = new DateTime(2014, 04, 14) },
new AvailableInventory { ID = 2, Date = new DateTime(2014, 04, 14) },
};
var query = AvailableInventory.GroupBy(i => i.Date)
.Where(g => SelectedProducts.All(s => g.Any(i => i.ID == s.ID)));
foreach(var group in query)
{
Console.WriteLine("Date: {0}", group.Key);
foreach(var inventory in group)
{
Console.WriteLine(" Available: {0}", inventory.ID);
}
}
This would output:
Date: 4/11/2014 12:00:00 AM
Available: 1
Available: 2
Date: 4/14/2014 12:00:00 AM
Available: 1
Available: 2

I think this is what you are looking for. Try this
var result = AvailableInventory.Where(i => SelectedProducts.Any(x => x.ID == i.ID)).GroupBy(o => o.Date)
.Select(g => g.First()).ToList();
This is the test data I used based on your class definition for AvailableInventory and SelectedProduct
// List of selected products from user
List<SelectedProduct> SelectedProducts = new List<SelectedProduct> {
new SelectedProduct { ID = 1, Qty = 2 },
new SelectedProduct { ID = 2, Qty = 4 },
new SelectedProduct { ID = 5, Qty = 10 }
};
// populated from service with all dates for all products
List<AvailableInventory> AvailableInventory = new List<AvailableInventory> {
new AvailableInventory { ID = 1, Date = new DateTime(2014, 04, 01) },
new AvailableInventory { ID = 2, Date = new DateTime(2014, 04, 02) },
new AvailableInventory { ID = 3, Date = new DateTime(2014, 04, 02) },
new AvailableInventory { ID = 4, Date = new DateTime(2014, 04, 10) },
new AvailableInventory { ID = 5, Date = new DateTime(2014, 04, 10) }
};
This should give you only the records with ID = 1, ID = 2 and ID = 5 because that's what common between both AvailableInventory and SelectedProducts lists.

It would help if you actually tried something.
Given this:
List<SelectedProduct> SelectedProducts ;
List<AvailableInventory> AvailableInventory ;
Something like this will probably get what you want:
int[] DatesWithAllSelectedProductsAvailable =
AvailableInventory
.GroupBy( x => x.Date )
.Where ( g => g.All( x => SelectedProducts.Any( p => p.ID == x.ID ) ) )
.Select( x => x.Key )
.Distinct()
.OrderBy( x => x )
.ToArray()
;