List all highest datarow or spezific datarow - linq

I have a table in which I use version numbers in each row. Now I would like to have only those records that have the highest version number of a category. But there are also some records that have a negative number, -1 to be precise. These should be selected instead.
An example
Version number|Categegory|Name
1 |SCHU |Shoes
2 |SCHU |new shoes
1 |HAND |Gloves
2 |HAND |New gloves
-1 |HAND |New gloves V2
I'd like to have a list that prints the following.
2 |SCHU|new shoes (Secundary, Selected because max VersionNo)
-1|HAND|New Gloves V2 (Primary, Selected because Special Version)
Translated with www.DeepL.com/Translator

You can use an expression to modify the sort value when it is -1 and then pick the highest value:
var ans = dt.AsEnumerable()
.GroupBy(r => r.Field<string>("Category"))
.Select(rg => rg.OrderByDescending(r => r.Field<int>("VersionNumber") == -1 ? Int32.MaxValue : r.Field<int>("VersionNumber")).First());
Note that the result is IEnumerable<DataRow> and not a DataTable. You can use the extension CopyToDataTable if you want to create a new DataTable containing the result rows.

Related

Powerquery: passing column value to custom function

I'm struggling on passing the column value to a formula. I tried many different combinations but I only have it working when I hard code the column,
(tbl as table, col as list) =>
let
avg = List.Average(col),
sdev = List.StandardDeviation(col)
in
Table.AddColumn(tbl, "newcolname" , each ([column] - avg)/sdev)
I'd like to replace [column] by a variable. In fact, it's the column I use for the average and the standard deviation.
Please any help.
Thank you
This probably does what you want, called as x= fctn(Source,"ColumnA")
Does the calculations using and upon ColumnA from Source table
(tbl as table, col as text) =>
let
avg = List.Average(Table.Column(tbl,col)),
sdev = List.StandardDeviation(Table.Column(tbl,col))
in Table.AddColumn(tbl, "newcolname" , each (Record.Field(_, col) - avg)/sdev)
Potentially you want this. Does the average and std on the list provided (which can come from any table) and does the subsequent calculations on the named column in the table passed over
called as x = fctn(Source,"ColumnNameInSource",SomeSource[SomeColumn])
(tbl as table, cname as text, col as list) =>
let
avg = List.Average(col),
sdev = List.StandardDeviation(col)
in Table.AddColumn(tbl, "newcolname" , each (Record.Field(_, cname) - avg)/sdev)

Google App Script: Remove blank rows from range selection for sorting

I want to sort real-time when a number is calculated in a "Total" column, which is a sum based on other cells, inputted by the user. The sort should be descending and I did achieve this functionality using the following:
function onEdit(event){
var sheet = event.source.getActiveSheet();
var range = sheet.getDataRange();
var columnToSortBy = 6;
range.sort( { column : columnToSortBy, ascending: false } );
}
It's short and sweet, however empty cells in the total column which contain the following formula, blanking itself if the sum result is a zero, otherwise printing the result:
=IF(SUM(C2:E2)=0,"",SUM(C2:E2))
It causes these rows with an invisible formula to be included in the range selection and upon descending sort, they get slapped up top for some reason. I want these blank rows either sorted to the bottom, or in an ideal scenario removed from the range itself (Without deleting them and the formula they contain from the sheet) prior to sorting.
Or maybe some better way which doesn't require me dragging a formula across an entire column of mostly empty rows. I've currently resorted to adding the formula manually one by one as new entries come in, but I'd rather avoid this.
EDIT: Upon request find below a screenshot of the sheet. As per below image, the 6th column of total points needs to be sorted descending, with winner on top. This should have a pre-pasted formula running lengthwise which sums up the preceding columns for each participant.
The column preceding it (Points for Tiers) is automatically calculated by multiplying the "Tiers" column by 10 to get final points. This column could be eliminated and everything shifted once left, but it's nice to maintain a visual of the actual points awarded. User input is entered in the 3 white columns.
You want to sort the sheet by the column "F" as the descending order.
You want to sort the sheet by ignoring the empty cells in the column "F".
You want to move the empty rows to the bottom of row.
You don't want to change the formulas at the column "F".
You want to achieve this using Google Apps Script.
If my understanding is correct, how about this answer?
Issue and workaround:
In the current stage, when the empty cells are scattered at the column "F", I think that the built-in method of "sort" of Class Range cannot be directly used. The empty cells are moved to the top of row like your issue. So in this answer, I would like to propose to use the sort method of JavaScript for this situation.
Modified script:
In order to run this function, please edit a cell.
function onEdit(event){
const columnToSortBy = 6; // Column "F"
const headerRow = 1; // 1st header is the header row.
const sheet = event.source.getActiveSheet();
const values = sheet.getRange(1 + headerRow, 1, sheet.getLastRow() - headerRow, sheet.getLastColumn())
.getValues()
.sort((a, b) => a[columnToSortBy - 1] > b[columnToSortBy - 1] ? -1 : 1)
.reduce((o, e) => {
o.a.push(e.splice(0, columnToSortBy - 1));
e.splice(0, 1);
if (e.length > 0) o.b.push(e);
return o;
}, {a: [], b: []});
sheet.getRange(1 + headerRow, 1, values.a.length, values.a[0].length).setValues(values.a);
if (values.b.length > 0) {
sheet.getRange(1 + headerRow, columnToSortBy + 1, values.b.length, values.b[0].length).setValues(values.b);
}
}
In this sample script, it supposes that the header row is the 1st row. If in your situation, no header row is used, please modify to const headerRow = 0;.
From your question, I couldn't understand about the columns except for the column "F". So in this sample script, all columns in the data range except for the column "F" is replaced by sorting. Please be careful this.
Note:
Please use this sample script with enabling V8.
References:
sort(sortSpecObj)
sort()
Added:
You want to sort the sheet by the column "F" as the descending order.
You want to sort the sheet by ignoring the empty cells in the column "F".
You want to move the empty rows to the bottom of row.
In your situation, there are the values in the column "A" to "F".
The formulas are included in not only the column "F", but also other columns.
You don't want to change the formulas.
You want to achieve this using Google Apps Script.
From your replying and updated question, I could understand like above. Try this sample script:
Sample script:
function onEdit(event){
const columnToSortBy = 6; // Column "F"
const headerRow = 1; // 1st header is the header row.
const sheet = event.source.getActiveSheet();
const range = sheet.getRange(1 + headerRow, 1, sheet.getLastRow() - headerRow, 6);
const formulas = range.getFormulas();
const values = range.getValues().sort((a, b) => a[columnToSortBy - 1] > b[columnToSortBy - 1] ? -1 : 1);
range.setValues(values.map((r, i) => r.map((c, j) => formulas[i][j] || c)));
}
A much simpler way to fix this is to just change
=IF(SUM(C2:E2)=0,"",SUM(C2:E2))
to
=IF(SUM(C2:E2)=0,,SUM(C2:E2))
The cells that are made blank when the sum is zero will then be treated as truly empty and they will be excluded from sort, so only cells with content will appear sorted at the top of the sheet.
Why your original formula doesn't work that way is because using "" actually causes the cell contain content so it's not treated as a blank cell anymore. You can test this by entering ISBLANK(F1) into another cell and check the difference between the two formulas.

how do I use linq to dataSet to convert dataTable to an array?

I have the following sql table schema:
procudtId productPrice Color
==================================
1 3 $ Blue
1 3 $ Red
1 3 $ Green
2 5 $ Blue
2 5 $ Red
Using c# code I got this into dataSet.
How can I use linq to dataSet to build an array that looks like
[ price:"3$", ColorList:<"Blue","Red","Green"> ;
price:"5$", ColorList:<"Blue","Red">]
Thanks
I think this will work:
//dt is the DataTable you're working with.
var groups = from row in dt.AsEnumerable()
group row["Color"] by row["productPrice"] into prices
select prices;
var query = from g in groups
select new
{
price = g.Key,
ColorList = g.ToList()
};
If that doesn't do it, let me know and I'll edit.
I think I'll do this in two steps:
1. create the color lists
var dataRows = from row in ds.Tables[0].AsEnumerable()
//group row by row.Field<Int32>("TierId")
where row.Field<Int32>("ProductId") == 1
select
row.Field<String>("Color");
List<String> list = dataRows.ToList();
2. acquire the product price
3. combine them both to array

Max sequence from a view containing multiple record using Linq lambda

I've been at this for a while. I have a data set that has a reoccurring key and a sequence similar to this:
id status sequence
1 open 1
1 processing 2
2 open 1
2 processing 2
2 closed 3
a new row is added for each 'action' that happens, so the various ids can have variable sequences. I need to get the Max sequence number for each id, but I still need to return the complete record.
I want to end up with sequence 2 for id 1, and sequence 3 for id 2.
I can't seem to get this to work without selecting the distinct ids, then looping through the results, ordering the values and then adding the first item to another list, but that's so slow.
var ids = this.ObjectContext.TNTP_FILE_MONITORING.Select(i => i.FILE_EVENT_ID).Distinct();
List<TNTP_FILE_MONITORING> vals = new List<TNTP_FILE_MONITORING>();
foreach (var item in items)
{
vals.Add(this.ObjectContext.TNTP_FILE_MONITORING.Where(mfe => ids.Contains(mfe.FILE_EVENT_ID)).OrderByDescending(mfe => mfe.FILE_EVENT_SEQ).First<TNTP_FILE_MONITORING>());
}
There must be a better way!
Here's what worked for me:
var ts = new[] { new T(1,1), new T(1,2), new T(2,1), new T(2,2), new T(2,3) };
var q =
from t in ts
group t by t.ID into g
let max = g.Max(x => x.Seq)
select g.FirstOrDefault(t1 => t1.Seq == max);
(Just need to apply that to your datatable, but the query stays about the same)
Note that with your current method, because you are iterating over all records, you also get all records from the datastore. By using a query like this, you allow for translation into a query against the datastore, which is not only faster, but also only returns only the results you need (assuming you are using Entity Framework or Linq2SQL).

How to use LINQ To Entities for filtering when many methods are not supported?

I have a table in SQL database:
ID Data Value
1 1 0.1
1 2 0.4
2 10 0.3
2 11 0.2
3 10 0.5
3 11 0.6
For each unique value in Data, I want to filter out the row with the largest ID. For example: In the table above, I want to filter out the third and fourth row because the fifth and sixth rows have the same Data values but their IDs (3) are larger (2 in the third and fourth row).
I tried this in Linq to Entities:
IQueryable<DerivedRate> test = ObjectContext.DerivedRates.OrderBy(d => d.Data).ThenBy(d => d.ID).SkipWhile((d, index) => (index == size - 1) || (d.ID != ObjectContext.DerivedRates.ElementAt(index + 1).ID));
Basically, I am sorting the list and removing the duplicates by checking if the next element has an identical ID.
However, this doesn't work because SkipWhile(index) and ElementAt(index) aren't supported in Linq to Entities. I don't want to pull the entire gigantic table into an array before sorting it. Is there a way?
You can use the GroupBy and Max function for that.
IQueryable<DerivedRate> test = (from d in ObjectContext.DerivedRates
let grouped = ObjectContext.DerivedRates.GroupBy(dr => dr.Data).First()
where d.Data == grouped.Key && d.ID == grouped.Max(dg => dg.ID)
orderby d.Data
select d);
Femaref's solution is interesting, unfortunately, it doesn't work because an exception is thrown whenever "ObjectContext.DerivedRates.GroupBy(dr => dr.Data).First()" is executed.
His idea has inspired me for another solution, something like this:
var query = from d in ObjectContext.ProviderRates
where d.ValueDate == valueDate && d.RevisionID <= valueDateRevision.RevisionID
group d by d.RateDefID into g
select g.OrderByDescending(dd => dd.RevisionID).FirstOrDefault();
Now this works.

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