How To Find Average In LINQ Query
May 3, 2010
I tried the following code:
Dim T5NHCEDCavg As Double
qry = From employee In empList
Where employee.HCEDC = False And employee.X5 = False _
Select employee.DCFSA
T5NHCEDCavg = qry.Average
But I'm getting a design-time error that says "Overload resolution failed because no accessible 'Average' accepts this number of arguments." I realize that I'm missing an overload here, but I'm not sure what to use or how to do this. I'm pretty new to LINQ. I've got a dataset in memory that I'm querying, and there is a double-precision property DCFSA, of which I'm trying to get the average based on my query above.
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Mar 21, 2012
I have users check off lab facilities in a UI. I want to use linq to fetch corresponding records for all of the labs that they have checked off. Basically,
Dim myRecs = (From l As EpiData In myDataContext.EPIDatas Where l.facility= _
one of the checked labs
So basically, I need to write a linq query where the "strings" to match are determined at runtime. Is there any way to do this easily? I know that there is a library out there called dynamic LINQ, but (1) it's in C# and I'm writing in VB (2) I'm really just looking for a single, simple solution for this single case.
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May 17, 2012
I have a data table that looks like this:
USERNAME ICOUNT IAVERAGE DATE_LOGGED
LAGX01 1245 1245 05-07-2012
LAGX02 2211 1422 05-07-2012
LAGX03 1698 1112 05-07-2012
LAGX04 4598 1555 05-07-2012
LAGX05 2589 3245 05-07-2012
LAGX06 3321 1155 05-07-2012
LAGX07 3698 3458 05-07-2012
LAGX08 2589 4587 05-07-2012
LAGX09 1598 1142 05-07-2012
LAGX10 3156 1987 05-07-2012
LAGX11 5547 2011 05-07-2012
LAGX12 9456 3459 05-07-2012
Now, I want to execute a sql query that will display the top 5 based on average, so i did this:
SELECT DISTINCT USERNAME,IAVERAGE FROM myTable WHERE IAVERAGE > 0 AND DATE_LOGGED='05-07-2012' ORDER BY IAVERAGE LIMIT 0,5 and the result is:
USERNAME ICOUNT IAVERAGE DATE_LOGGED
LAGX03 1698 1112 05-07-2012
LAGX09 1598 1142 05-07-2012
LAGX06 3321 1155 05-07-2012
LAGX01 1245 1245 05-07-2012
LAGX02 2211 1422 05-07-2012
Now, I want to numberize my query result, so it will look like this:
RANK USERNAME ICOUNT IAVERAGE DATE_LOGGED
1 LAGX03 1698 1112 05-07-2012
2 LAGX09 1598 1142 05-07-2012
3 LAGX06 3321 1155 05-07-2012
4 LAGX01 1245 1245 05-07-2012
5 LAGX02 2211 1422 05-07-2012
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Sep 22, 2009
I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.
For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.
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Apr 9, 2011
I need help on how can I transfer a query from Access to LinQ that calculate the average in time per transaction during a given date.the working Access query is:
Avg(DateDiff("s",CVDate(Format([start_time],"hh:nn:ss")),CVDate(Format([finish_time],"hh:nn:ss")))) AS Expr1, Format([Expr1]3600,"00") & ":" & Format(([Expr1]60) Mod 60,"00") & ":" & Format([Expr1] Mod 60,"00") AS format
How can I port this to LinQ?
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Mar 22, 2010
Heres my code so far:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim Subject As Integer
Subject = InputBox("How many products")
[code]...
Only "0" appears in the TextBox2 and not the average number.
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Apr 25, 2011
What is the formula in VB for finding the average of two integers?I know in normal math it is e.g. (4 + 6) / 2 it only needs to be the average of two values.
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Feb 8, 2009
I am tring to find the Average Temp for the days entered,and I am not sure how to do this.Here is the code I have so far:
Public Class Form1
Dim Temp(6) As Single
[code].....
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May 14, 2012
I wrote the following generic LINQ extension for calculating weighted average in Visual Basic 2010:
<Extension()>
Function WeightedAverage(Of T)(ByVal source As IEnumerable(Of T),
ByVal selectorValue As Func(Of T, Integer),
ByVal selectorWeight As Func(Of T, Integer)) As Double
Dim weightedValueSum As Double
Dim weightSum As Integer
[Code] .....
How can I call this function as an Aggregate function of another LINQ query? I tried it in the following way:
Dim q1 = From jd In oContext.JobDatas
Where jd.Year = 2011
Select jd
Dim q2 = Aggregate num In q1 Into WeightedAverage(num.AvSalary, num.NumPosHolder)
The Visual Basic 2010 editor is telling me that the second query (q2) of the following code is not valid statement. On the comma between the first an second argument it's saying: ")" required.
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Jun 6, 2011
i created an array of 100 cells, and the user inputs the value into them now i have to find the average of the array but not all of the cells are used how do i go to the last value, instead of the last cell? [code]
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Jan 28, 2009
I've got an arrayList full of ints, how do i find the average value in it?
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Jan 5, 2012
I'm having a little problem with my code as it follows, im trying to find the average # between 1-10 that is selected in my listbox but i'm having problems with my counter that divides it by, as a result i am only getting the number selected Goal is to select a value in listbox and find average based on what is selected and how many values were selected
Public Class Form1
Private Sub xRecordScoreButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles xRecordScoreButton.Click
[Code].....
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Dec 15, 2011
I have a table called tblComparison - this table has the following columns[code]...
Once the averages for each column are created it needs to save them to tblMonthlyComparison - again the column names in this table are the same so in the fldDate column the program needs to enter 31/12/2011. In fldAverage of this table what we do is take the average that we found above for each column then plus them together and divide them by 5.
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May 21, 2011
Anyone can give the coding for finding the longest & average length?(displayed in a messagebox)
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Jan 12, 2012
I am trying to make an application that would use an inputbox that will enter numbers until the user enters -1 after the numbers were entered and the user entered -1 the numbers would display within the listbox and the average would be in a label displaying "The average number is" & averagenumber in my current application I have it from 1-5 my question is how would i allow it to enter an unknown amount of numbers and create an counter for it.
Public Class Form1
Private counter As Integer
Private item As Double
Private average As Double
Private numbers As Double
[Code] .....
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May 26, 2009
I was working on some code in VB.NET 2008 and somehow got a bunch of new functions to pop up in intellisense on a datarow array. I saw find, findfirst, sort, average, and lots more. They had an icon next to them in intellisense when I saw them. Then I went and changed some of the code and now I can't get them to come back. I have used 2005 and 2003 for a long time, but still pretty new to 2008.
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Apr 3, 2012
How can I find a listbox average removing the 2 lowest number? I tried
DimintSmall
AsInteger
intSmall = lstGrades.Items.Item(0)
ForEachItem
AsIntegerInlstGrades.Items
IfItem < intSmall
Then
intSmall = Item
EndIf
Next
lstGrades.SelectedItem = intSmall
I cant select or remove it
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Mar 11, 2010
I am new to VB and need to make a program that does the following:Write a VB.Net program that allows users to enter a series of numbers(separated by a comma) in a text box called series. When the users clicks the command button called Average, the program extracts the number one by one from the series and calculates the average, and outputs the average onto a textbox called Result.I understand how to get it to do the average, but how can I make the program count the numbers that I input and then divided by the sum? Also, how would i get it started.
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Jul 14, 2011
given this function:
Public Function Search(ByVal StartIndex As Integer, _
ByVal MaxResults As Integer, _
ByVal AccountNumber As String, _
ByVal LastName As String, _
[Code]....
instead of what I expected:
Select count(*) from remitline where lastname = "smith"
What am I doing wrong building up the where clause? I'm using Castle ActiveRecord 2.1
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Aug 6, 2009
if there is that much of a performance gain in running a LINQ stored procedure versus a LINQ query?
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Sep 14, 2010
I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.
I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.
The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.
Protected Sub LoadResults()
'Get Dictionary of Filters
Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary")
' Initialize LinqToSql
[code]....
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Mar 31, 2011
Forgive my ignorance on this.I have this LINQ Query:Dim ngBikersDataContext As New CarBikeWalkDataContext
bikersList = (From c In ngBikersDataContext.Reg_Bikers _
Order By c.L_Name _
Select New Bikers() With { _
.BikerID = c.BikerID, _
.F_Name = c.F_Name, _
[Code]...
with the error "Overload resolution failed because no accesible 'Select' accepts this number of arguments."
Over the "NEW" I get an error " ')'expected."
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Jun 21, 2012
I am trying to program a noise reduction algorithm that works with a set of datapoints in a VB.NET DataTable after being helped with my other question. Basically, I want to take two integers, a coordinate value (yCoord for example) and a threshold smoothing value (NoiseThresh), and take the average of the values in the range of (yCoord - NoiseThresh, yCoord + NoiseThresh) and store that number into an array. I'd repeat that process for each column (in this example) and end up with a one-dimensional array of average values. My questions are:
1) Did anything I just say make any sense ;), and
2) Can anyone help me with the code? I've got very little experience working with databases.
[Code]...
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Aug 27, 2010
The database:
"ID (Primary key)" | "Title"
0 | "title1"
[code].....
OK, before adding values to database, we should check if a row exists with this values :)TO do this, creating a Stored Procedure is a best way to deal with the database fastly.So... The problem now is, at the runtime, Miss OleDB throw this error:Microsoft Jet database engine cannot find the input table or query 'IF
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May 29, 2009
i should say hi experts :D . Help me with this pretty code :)
The database:
"ID (Primary key)" | "Title"
0 | "title1"
[code].....
OK, before adding values to database, we should check if a row exists with this values :)TO do this, creating a Stored Procedure is a best way to deal with the database fastly.So... The problem now is, at the runtime, Miss OleDB throw this error:Microsoft Jet database engine cannot find the input table or query 'IF
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Jun 15, 2010
I want to include an average in a column where the average ignores zero values in a report cell where the column may have
17
19
0
[code].....
I want 16, not 11 so (17 + 19 + 12 + 13 + 19) / 5 not (17 + 19 + 0 + 0 + 12 + 13 + 19) / 7 Something like this if it would work.
=SUM(Fields!fieldname.Value) / Count(iif(Fields!count_cycle_per_hour.Value >= 0,Fields!fieldname.Value,0))
Essentially just average everything in the column NOT a zero?
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Jan 27, 2011
We are doing a query against an in-memory collection of LINQ data objects. The wrinkle is that we are ordering by a column in a related table whose records have not necessarily been loaded yet (deferred loading:)
Dim oPkgProducts = _
From b In oBillPkg.BillProducts _
Where b.Successful.GetValueOrDefault(Common.X_INDETERMINATE) = _
[code]....
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Aug 31, 2011
How do I add ROW_NUMBER to a LINQ query or Entity? How can I convert this solution to VB.NET?
[Code]...
I'm having trouble porting that last line. I have been unable to locate a VB.NET example. I'm actually not looking for any paging functionality like the example provides, just good old-fashioned Row_Number(Order By X) row index.
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Sep 8, 2009
I'm working on a function to return a exponential average and there are a lot of examples of exponential moving averages but they all start with a moving average that is just the mean as a lead in to calculating the continuing moving average. I needed just a exponential average of a value set. After Googling my Bing off I still haven't seen anything so here is my attempt at a basic exponential average. Is this correct? Are there any errors? I have seen some text about adding a smoothing value to change the curve of the exponential average but not how that would be implemented.
[Code]...
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Apr 16, 2011
I was wandering is it possible to use a query within another query below is the code I am trying to use.
Public Function GetInventByComp(ByVal CompID As String) Using DC As New DataClassDataContext
'need to get company id's based off names? thats bad should be name from Id need to rethink this
Dim invent = (From C In DC.Inventors_Companies _
Where C.CompID = CompID _
Select C.InventorID).ToString
[Code]...
I was trying to us multiple values in a string like "1, 3, 5" but I can't seem to get that working either so I am trying to use just a single value now. Can anyone help me? "Yes I am new to this"
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