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Group by column values with spaces Using linq

I have got this situation with a datatable like this
C1 C2 C3
A AA 4
BB 6
B CC 3
DD 3
EE 4
C FF 5
GG 5
and my output should be like this
C1 C2 C3
A AA,BB 10
B CC,DD,EE 10
C FF,GG 10
How can i group by the column with the space till the next value comes up
What i did was i took all the row itemarray and then using some string manipulation and regex got the row value as for the first two values like this and assigned to a variable in a query using Let
A,AA,BB,10|B,CC,DD,EE,10 but then i cannot add it using the
**DT.clone.rows.Add(x.split("|"c))* method as there its not incrementing and adding the whole joined string
Any other input where i can manipulate and add it (P.S i know linq is querying language)
Thank you for your time

You can use .GroupBy to get result needed
Here is your class:
public class Data
{
public string C1 { get; set; }
public string C2 { get; set; }
public int C3 { get; set; }
}
Imagine that you have list of Data objects, so your GroupBy expression will be following:
var result = list.GroupBy(g => g.C1, (a, b) => new {C1 = a, C2 = b.ToList()})
.Select(g => new
{
g.C1,
C2 = string.Join(",", g.C2.Select(m => m.C2)),
C3 = g.C2.Sum(m => m.C3)
})
.ToList();

A simple .GroupBy can give you expected result, Edited to handle Null or WhiteSpace Columns
var res = ListModel.Where(e => !string.IsNullOrWhiteSpace(e.C1)
&& !string.IsNullOrWhiteSpace(e.C2))
.GroupBy(e => e.C1).Select(e => new
{
e.Key,
c2 = string.Join(",", e.Select(x => x.C2).ToList()),
c3 = e.Sum(x => x.C3)
}).ToList();

Hello All first of all Thank you for your time and effort i Did this use case using this code
This gave me all row item array in string and than in the end with a little Split method i was able to add it to my datatable
String.Join("|",(System.Text.RegularExpressions.Regex.Replace(String.Join("|",(From roww In DT.AsEnumerable() Select String.Join(",",roww.ItemArray) ).ToList),"\|,",",")).Split("|"c).
Select(Function(q)CStr(q)+","+CStr(String.join("|",System.Text.RegularExpressions.Regex.Matches(CStr(q),"\d+").Cast(Of match)).Split("|"c).Sum(Function(r) CInt(r) ))).tolist),",\d+,",",")```

Try following code which is tested
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
DataTable dt1 = new DataTable();
dt1.Columns.Add("C1", typeof(string));
dt1.Columns.Add("C2", typeof(string));
dt1.Columns.Add("C3", typeof(int));
dt1.Rows.Add(new object[] { "A", "AA", 4});
dt1.Rows.Add(new object[] { null, "BB", 6});
dt1.Rows.Add(new object[] { "B", "CC", 3});
dt1.Rows.Add(new object[] { null, "DD", 3});
dt1.Rows.Add(new object[] { null, "EE", 4});
dt1.Rows.Add(new object[] { "C", "FF", 5});
dt1.Rows.Add(new object[] { null, "GG", 5});
//replace nulls in column 1 with actual values
string previous = "";
foreach(DataRow row in dt1.AsEnumerable())
{
if (row.Field<string>("C1") == null)
{
row["C1"] = previous;
}
else
{
previous = row.Field<string>("C1");
}
}
DataTable dt2 = dt1.Clone();
var groups = dt1.AsEnumerable().GroupBy(x => x.Field<string>("C1")).ToList();
foreach (var group in groups)
{
dt2.Rows.Add(new object[] {
group.Key,
string.Join(",", group.Select(x => x.Field<string>("C2"))),
group.Select(x => x.Field<int>("C3")).Sum()
});
}
}
}
}

Yet another way using Skip, TakeWhile, and GroupBy extensions:
DataTable dt1 = new DataTable();
dt1.Columns.Add("C1", typeof(string));
dt1.Columns.Add("C2", typeof(string));
dt1.Columns.Add("C3", typeof(int));
//The output table.
DataTable dt2 = dt1.Clone();
dt1.Rows.Add(new object[] { "A", "AA", 3 });
dt1.Rows.Add(new object[] { null, "BB", 6 });
dt1.Rows.Add(new object[] { "B", "CC", 3 });
dt1.Rows.Add(new object[] { null, "DD", 3 });
dt1.Rows.Add(new object[] { null, "EE", 4 });
dt1.Rows.Add(new object[] { "C", "FF", 5 });
dt1.Rows.Add(new object[] { null, "GG", 6 });
var rows = dt1.Rows.Cast<DataRow>().AsEnumerable();
foreach (var row in rows.Where(r => r.Field<string>("C1") != null))
{
var indx = dt1.Rows.IndexOf(row) + 1;
var q = rows
.Skip(indx)
.TakeWhile(t => t.Field<string>("C1") == null)
.GroupBy(g => g.Field<string>("C1"))
.Select(g => new
{
C1 = row.Field<string>("C1"),
C2 = $"{row.Field<string>("C2")}, {string.Join(", ", g.Select(s => s.Field<string>("C2")))}",
C3 = row.Field<int>("C3") + g.Sum(s => s.Field<int>("C3")),
}).FirstOrDefault();
if (q != null)
dt2.Rows.Add(q.C1, q.C2, q.C3);
}
dataGridView1.DataSource = null;
dataGridView1.DataSource = dt2;
The idea behind this snippet is to:
Get the complete rows and iterate through them.
For each complete row, we get it's index from the original DataTable and add 1 to make a starting search point for the incomplete rows. The Skip extension is the method to achieve that.
The TakeWhile extension function gets the incomplete rows and stops at the next complete row.
The GroupBy extension function groups the incomplete rows to concatenate their C2 values and sum their C3 values, add the results to the values of the complete row and create a temporary anonymous object to hold these values.
Extract the anonymous object and add a new DataRow to the output DataTable.
And finally, bind the output DataTable to a DGV.
Happy 2020 for all.

How to get count of duplicate values with value name

I'm pretty new with Elasticsearch, I'm using NEST library. How can I get count of duplicate values?
Here is my class:
public class Book
{
public string BookName {get;set;}
public string Author {get;set;}
}
This is my data:
BookName=X, Author=a<br>
BookName=Y, Author=a<br>
BookName=Z, Author=b<br>
BookName=C, Author=b<br>
BookName=T, Author=c<br>
Query result should be:
a- 2
b- 2
c- 1
I tried the following query but it doesn't work:
client.Search<Book>(s => s
.Aggregations(a => a
.Terms("group_by_auth", ts => ts
.Field(o => o.Author)
.Size(10)
.Aggregations(aa => aa
.Sum("sum_value", sa => sa
.Field(o => o.Author)
)
)
)
));
Mapping is:
client= new ElasticClient(connectionSettings);
client.CreateIndex("books", c => c
.Mappings(m => m
.Map<Book>(mm => mm
.Properties(ps=>ps
.Text(s=>s
.Name(a=>a.Author)
)))
)

If you want the count of the terms you can get it like so
var uri = new Uri("http://localhost.fiddler:9200");
ElasticClient db = new ElasticClient(uri);
var data = new[] {
new{ BookName= "X", Author="a" },
new{ BookName= "Y", Author="a" },
new{ BookName= "Z", Author="b" },
new{ BookName= "C", Author="b" },
new{ BookName= "T", Author="c" },
};
db.DeleteIndex("test");
foreach (var d in data)
{
db.Index(d, id => id.Index("test"));
}
System.Threading.Thread.Sleep(1000);
var items = db.Search<dynamic>(s => s.Size(0).Aggregations(aggr => aggr.Terms("group_by_auth", ts => ts.Field("author.keyword"))));
foreach (var item in items.Aggs.Terms("group_by_auth").Buckets)
{
Console.WriteLine(item.Key + "-" + item.DocCount);
}
Console.WriteLine("DONE");
Console.ReadLine();

Return Unique values and Sum LINQ

I have two tables:
Retailers
Invoices
Retailers has two columns:
1.1. RetailerID
1.2. RetailerName
Invoices has three columns:
2.1. InvoiceID
2.2. InvoiceProfit
2.3. RetailerID
Retailers.RetailerID is linked to Invoices.RetailerID (one-to-many).
What I want to do is write a linq (or in the form of a lambda exp) that returns Retailer.RetailerID, Retailer.RetailerName, Invoice.InvoiceProfit.
I can do this like so:
var retailers = from r in db.Retailers select t;
var invoices = from i in db.Invoices select i;
var retailersAndInvoices = from r in retailers join i in invoices on r.RetailerID equals i.RetailerID select new {t.RetailerName, i.InvoiceProfit};
I want to return only Distinct RetailerNames and the Sum of all Invoices.InvoiceProfit next to each one - the purpose being "Top Ten Retailers"!
How can i do this?

Use GroupBy to convert a flat list to groups by RetailerName
Use Sum(i => i.InvoiceProfit) to compute totals
Use new { ... } to pair up retailers with their profit totals
Use OrderByDescending(p => p.TotalProfit) to get high-profit retailers to the top
Use Take(10) to limit the list to ten items.
Overall query would look like this:
var topTen = retailersAndInvoices
.GroupBy(ri => ri.RetailerName)
.Select(g => new {
Retailer = g.Key
, TotalProfit = g => g.Sum(i => i.InvoiceProfit)
})
.OrderByDescending(p => p.TotalProfit)
.Take(10)
.ToList();

I use combination of lambda and linq. See msdn : https://code.msdn.microsoft.com/LINQ-Join-Operators-dabef4e9
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication28
{
class Program
{
static void Main(string[] args)
{
DataTable retailers = new DataTable();
retailers.Columns.Add("RetailerID", typeof(int));
retailers.Columns.Add("RetailerName", typeof(string));
retailers.Rows.Add(new object[] { 123, "abc" });
retailers.Rows.Add(new object[] { 124, "abd" });
retailers.Rows.Add(new object[] { 125, "abe" });
DataTable invoices = new DataTable();
invoices.Columns.Add("InvoiceID", typeof(int));
invoices.Columns.Add("InvoiceProfit", typeof(decimal));
invoices.Columns.Add("RetailerID", typeof(int));
invoices.Rows.Add(new object[] { 100, 200, 123 });
invoices.Rows.Add(new object[] { 101, 201, 123 });
invoices.Rows.Add(new object[] { 102, 202, 123 });
invoices.Rows.Add(new object[] { 103, 203, 123 });
invoices.Rows.Add(new object[] { 104, 204, 124 });
invoices.Rows.Add(new object[] { 105, 205, 124 });
invoices.Rows.Add(new object[] { 106, 206, 124 });
invoices.Rows.Add(new object[] { 107, 207, 125 });
invoices.Rows.Add(new object[] { 108, 208, 125 });
invoices.Rows.Add(new object[] { 109, 209, 125 });
var retailersAndInvoices = (from r in retailers.AsEnumerable()
join i in invoices.AsEnumerable() on r.Field<int>("RetailerID") equals i.Field<int>("RetailerID")
select new { name = r.Field<string>("RetailerName"), profit = i.Field<decimal>("InvoiceProfit") })
.GroupBy(x => x.name)
.Select(x => new { name = x.Key, totalProfit = x.Select(y => y.profit).Sum() }).ToList();
}
}
}

Firebird group by period

I am pulling some historical data from Firebird database as below:
Product_ID Date Price
1 2001-01-01 10
1 2001-02-01 10
1 2001-03-01 15
1 2001-04-01 10
1 2001-05-01 20
1 2001-06-01 20
What I am trying to do is to extract the first for occurrence every price change.
Example of expected data set:
Product_ID Date Price
1 2001-01-01 10
1 2001-03-01 15
1 2001-04-01 10
1 2001-05-01 20
I know that on MSSQL I could leverage LAG for that. Is it possible to do that with Firebird?

You can try this, but be aware I didn't tested it:
CREATE PROCEDURE SP_Test
RETURNS (
Product_ID INTEGER,
Date DATE,
Price INTEGER
)
AS
DECLARE VARIABLE Last_Product_ID INTEGER;
DECLARE VARIABLE Last_Date DATE;
DECLARE VARIABLE Last_Price INTEGER;
BEGIN
FOR SELECT Product_ID, Date, Price
FROM xxxx
ORDER BY Product_ID, Date
INTO Product_ID, Date, Price
DO BEGIN
IF ((:Last_Product_ID IS NULL) OR
(:Last_Date IS NULL) OR
(:Last_Price IS NULL) OR
(:Product_ID <> :Last_Product_ID) OR
(:Price <> :Last_Price)) THEN
SUSPEND;
Last_Product_ID = :Product_ID;
Last_Date = :Date;
Last_Price = :Price;
END;
END;

in MoreLinq there is a Lag extension method but it is supported only in Linq to Objects...
What you can do, if you are looking for a C# linq answer for that you can:
Basically order your data the correct way and then add a row index for while price (and product_id) is still the same. Then group by it and select the min date.
int groupingIndex = 0;
int previousPrice = 0;
var response = data
.OrderBy(item => item.Product_ID)
.ThenBy(item => item.Date)
.Select(item =>
{
if (item.Price != previousPrice)
{
previousPrice = item.Price;
groupingIndex++;
}
return new { Index = groupingIndex, Item = item };
})
.GroupBy(item => new { item.Index, item.Item.Product_ID, item.Item.Price } )
.Select(group => new Record
{
Product_ID = group.Key.Product_ID,
Price = group.Key.Price,
Date = group.Min(item => item.Item.Date)
}).ToList();
And if you don't mind doing the operation in the C# and not the DB (and using a beta version of the MoreLinq) then:
int index = 0;
var result2 = data
.OrderBy(item => item.Product_ID)
.ThenBy(item => item.Date)
.Lag(1, (current, previous) => new { Index = (current.Price == previous?.Price ? index : ++index), Item = current })
.GroupBy(item => new { item.Index, item.Item.Product_ID, item.Item.Price })
.Select(group => new Record { Product_ID = group.Key.Product_ID, Price = group.Key.Price, Date = group.Min(item => item.Item.Date) })
.ToList();

This is a little complicated but it works
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication6
{
class Program
{
static void Main(string[] args)
{
DataTable dt = new DataTable();
dt.Columns.Add("Product_ID", typeof(int));
dt.Columns.Add("Date", typeof(DateTime));
dt.Columns.Add("Price", typeof(int));
dt.Rows.Add(new object[] {1, DateTime.Parse("2001-01-01"), 10});
dt.Rows.Add(new object[] {1, DateTime.Parse("2001-02-01"), 10});
dt.Rows.Add(new object[] {1, DateTime.Parse("2001-03-01"), 15});
dt.Rows.Add(new object[] {1, DateTime.Parse("2001-04-01"), 10});
dt.Rows.Add(new object[] {1, DateTime.Parse("2001-05-01"), 20});
dt.Rows.Add(new object[] {1, DateTime.Parse("2001-06-01"), 20});
dt.Rows.Add(new object[] { 2, DateTime.Parse("2001-01-01"), 10 });
dt.Rows.Add(new object[] { 2, DateTime.Parse("2001-02-01"), 10 });
dt.Rows.Add(new object[] { 2, DateTime.Parse("2001-03-01"), 15 });
dt.Rows.Add(new object[] { 2, DateTime.Parse("2001-04-01"), 10 });
dt.Rows.Add(new object[] { 2, DateTime.Parse("2001-05-01"), 20 });
dt.Rows.Add(new object[] { 2, DateTime.Parse("2001-06-01"), 20 });
dt = dt.AsEnumerable().OrderBy(x => x.Field<DateTime>("Date")).CopyToDataTable();
List<DataRow> results = dt.AsEnumerable()
.GroupBy(g => g.Field<int>("Product_ID"))
.Select(g1 => g1.Select((x, i) => new { row = x, dup = (i == 0) || ((i > 0) && (g1.Skip(i - 1).FirstOrDefault().Field<int>("Price") != g1.Skip(i).FirstOrDefault().Field<int>("Price"))) ? false : true })
.Where(y => y.dup == false).Select(z => z.row)).SelectMany(m => m).ToList();
}
}
}

Linq Grouping the result of group by query

I have the following exemple :
Model mod1 = new Model { Header = "A", canDelete = true,pax=1 };
Model mod2 = new Model { Header = "B", canDelete = true,pax=1 };
Model mod3 = new Model { Header = "A", canDelete = true,pax=2 };
Model mod4 = new Model { Header = "B", canDelete = false,pax=2 };
Model mod5 = new Model { Header = "A", canDelete = true,pax=3 };
Model mod6 = new Model { Header = "B", canDelete = false,pax=3 };
Model mod7 = new Model { Header = "A", canDelete = false,pax=4 };
Model mod8 = new Model { Header = "B", canDelete = true,pax=4 };
I added these models to a listMod
I want to group first by pax number, so I used :
var resultQuery = listMod.GroupBy(p=>p.pax);
How can I re-group the result of my resultQuery by Header and canDelete ?
The aim is to have 3 groups :
1st group : mod1 and mod2
2nd group : mod3 , mod4 , mod5 and mod6
3rd group : mod7 and mod8

Well, there may be a better way, but this one should work, assuming you have always two items for each pax number.
The "trick" is to concatenate the first and second canDelete / Header pair of items grouped by pax, and to group on that value.
Than the list inside the groups are flattened (using SelectMany)
listMod.GroupBy(m => m.pax)
.Select(m => new
{
valuePair = string.Format("{0}-{1}/{2}-{3}", m.First().canDelete, m.First().Header, m.Last().canDelete, m.Last().Header),
value = m.Select(x => x)
})
.GroupBy(m => m.valuePair)
.Select(g => g.SelectMany(x => x.value))
//.ToList();
if you wanna avoid this bad concatenation, you can also do
var result = listMod
.GroupBy(m => m.pax)
.Select(m => new
{
a1 = m.First().canDelete,
a2 = m.First().Header,
b1 = m.Last().canDelete,
b2 = m.Last().Header,
value = m.Select(x => x)
})
.GroupBy(m => new {m.a1, m.a2, m.b1, m.b2})
.Select(g => g.SelectMany(x => x.value))
//.ToList();