LINQ - Calculate Variance With Lambda Expression

Feb 3, 2011

I am trying to convert the following code for the variance calculation
public static double Variance(this IEnumerable<double> source){
double avg = source.Average();
double d = source.Aggregate(0.0,
(total, next) => total += Math.Pow(next - avg, 2));
return d / (source.Count() - 1);
}
Described on CodeProject into corresponded VB.NET lambda expression syntax, but I am stuck in the conversion of Aggregate function. How can I implement that code in VB.NET?

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Linq - Examples Of .NET Lambda Expression?

Feb 3, 2011

Where can I find complex LINQ examples made using VB.NET Lambda Expression syntax?During my searches I always found 101 LINQ Samples but they use the other notation and for me is not always clear how to transform that code into a lambda expression.

Set An Indexing Variable In Linq/Lambda Expression?

Apr 16, 2010

I have a lambda expression that builds a list ofanonymous types. I would like to include a property in the anonymous type that is a counter. So the first entry is 1, second 2, third 3, and so on.I thought I recallenyone know the syntax for defining an indexing variable as part of a Linq query or lambda expression?

View 10 Replies

Can A LINQ Or A LAMBDA Expression Be Used To Count The 1's In A Binary String Or Char Array

Sep 15, 2010

Can a LINQ or a LAMBDA expression be used to count the 1's in a binary string ?For example, if I convert a number to its BINARY using.>>

Dim binaryString As String = Convert.ToString( numberVariable, 2 )

1) Without using a loop such as a FOR NEXT loop, can I count the number of 1's in the STRING using LINQ or a LAMBDA expression?

2) Can I get the indexes of where the 1's are at in a collection such as a LIST using LINQ or a LAMBDA expression?I know the syntax of some LINQ expressions, however, I don't know which method may be suitable.

Calculate Variance And Std Dev

Apr 30, 2009

how i'd solve for variance and Std. deviation. the project is meant to record housing prices, put them in a list box, and then compute these calculations

Public Class Form1
Dim intclicks As Integer = 0
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub

[code]....

Calculate VARIANCE Or STDDVE Of A Field

Mar 8, 2012

How can I calculate standard deviation and variance of a field in my database by using OleDb and SQL language in vb 2010. I used VARIANCE and STDDVE and VAR_SAMP but they are undefined. There is other function for do this or there is any way to define this kind of SQL functions to
OleDb?

Delegate 'System.Threading.ThreadStart' Requires An 'AddressOf' Expression Or Lambda Expression As The Only Argument To Its Constructor?

Jan 23, 2010

I got this Error. below is my code.

GenerateTheList is function.Need help
Private Sub buttGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttGenerate.Click
Dim thread1 As New Thread(New ThreadStart(GenerateTheList))
thread1.Start()
End Sub

Calculate Variance Of A Coloum In My Datatable Object - Tabletable.compute("Var()", Filter )

May 14, 2009

I want to calculate variance of a col in my datatable object. If i apply datatable.compute(Var(...)), i gives a negative result. Variance can't be negative. And it I just apply it to half of the data, it works fine. Does datatable.compute has a limited capacity?

AddressOf' Expression Or Lambda Expression

Feb 22, 2009

From this code

[Code]...

If I put New Action(AddressOf PrivateMesage), then I get the following error: Bounds can be specified only for the top-level array when initializing an array of arrays. on the following code

[Code]...

C# - Lambda Expression: CS To .Net?

Aug 24, 2011

I am dumb founded at this statement....maybe its just too many hours/days of doing C# to VB.Net conversion but i am drawing a blank on this conversion.

List<string> sColors = new List<string>(this.CustomPaletteValues.Split(','));
try {
List<Color> colors = sColors.ConvertAll<Color>(s => (Color)(new ColorConverter().ConvertFromString(s)));

What i have so far:

Dim colors As List(Of Color) = sColors.ConvertAll(Of Color)(....)

As you can see its the content of the lambda that i am hitting a brick wall with.

.net - Convert C# Lambda Expression To VB?

Mar 23, 2012

In looking at Fuzzy Date Time Picker Control in C# .NET? Piotr Czaapla's answer to that question is exactly what I need. unfortunately, I'm a VB.NET guy and I'm not that familiar with lambda expresions, so my attempts to convert the code have resulted in hours of misplaced parenthesis and banging my head with a brick.

Any chance some bi-lingual wizard could convert the C# code to VB.net for me?

[Code]...

.Net Lambda Expression With No Intellisense?

Mar 9, 2011

Using lambda's in VB.Net results in no intellisense. Is this a bug with VS2010 or expected? Note that it works fine in C#

Return Array.TrueForAll(chequeColl, Function(x) x.Number <> "N") 'No intellisense Number does not appear
Return Array.TrueForAll(chequeColl, Function(x As MyClass) x.Number <> "N") 'Now casted intellisense appears

UPDATE: Here's an example

Public Class Cheque
Public Property Id As String
Public Property Status As Byte

[code]....

Convert C# Lambda += Expression To VB?

Feb 15, 2011

How should the following C# code be converted to VB.Net? I have tried several code converters and none produce correct results.

[code]...

Converting A C# Lambda Expression?

Dec 15, 2011

I will probably sound like a bad developer here, but I am attempting to convert some code from the following page from C# to VB.NET:The code I am having trouble converting is from Step 4 of "Joining a Multicast Group" on the page, and here is the code with the comment lines removed:

private void Join()
{
_receiveBuffer = new byte[MAX_MESSAGE_SIZE];

[code].....

Extract The Lambda From An Expression?

Aug 9, 2010

I want to implement this function:

Public Function GetFunc(Of TSource, TResult) _
selector As Expression(Of Func(Of TSource, TResult)) _
As Func(Of TSource, TResult)

[code]....

UPDATE:I have the following issue, it's a part of a function:

Dim obj As Object = value
For Each exp In expressions
If obj Is Nothing Then Return [default]

[code]....

Exception Details:

ArgumentException:Object of type 'System.Linq.Expressions.Expression`1 [System.Func`3[System.Char,System.Char,System.Char]]'cannot be converted to type 'System.Func`3[System.Char,System.Char,System.Char]'.

Lambda Expression Not Working?

Jun 12, 2012

If been try to convert some code I have from VB.net to C# but I just cannot get it working!first is the vb code I'm only interested in the line that has the Lambda Expression for the C#[code]......

Lambda Expression Shorthand

Mar 30, 2010

Currently, I have code similar to this:

xxx, _
If(dr.Table.Columns.Contains("EnterpriseID"), dr.Field(Of Integer)("EnterpriseID"), -1), _
xxx

I would like to create a Lamdba expression something like the following (this doesn't work):

Dim xCol As Func(Of DataRow, String, Type, Object, Object) = _
Function(dr, x, t, dflt) _
If(dr.Table.Columns.Contains(x), dr.field(Of t)(x), dflt)

So that I can say something like:

xxx, _
xCol(dr, "EnterpriseID", GetType(System.Integer), -1), _
xxx

Trick Lambda Expression In VB

May 8, 2009

I know in VB Lambda expressions must return a value and can only have one statement. But in my case I just need to execute a Sub that does not return a value. Is there a way to trick it by somehow returning a dummy value yet still call my Sub? If possible what would the syntax be like?

Using The Vb Equivilant Of The MAX Lambda Expression

Apr 7, 2011

I am having an issue using the vb equivilant of the MAX lambda expression. at foos.Max(function(x) x.id) when I try to intellisense the property ID VS will not show it. But when i run the example it works. Is there something I am doing which is wrong, an i am just lucky it runs? [Code]

VB Lambda Expression For Sub Delegate?

Nov 29, 2010

There is the code:

Private Sub InsertItemInCache(Of T)(ByVal item As CachedItem(Of T), ByVal dependency As AggregateCacheDependency, _
ByVal key As String, ByVal updateCallBack As CacheItemUpdateCallback)

[code].....

C# - Using Iteration Variable In A Lambda Expression?

Feb 16, 2012

[URL]..Module Module1

[Code]...

It says the result will always be 5 namely the final value of i. How come?

They don't put the iteration variable in the "closure"?

Creating A Lambda Expression With Delegate?

Jul 16, 2010

I am Creating a Lambda Expression, but it' not getting me the write Out put :

Public Class Form1
Delegate Function GetLastChar(ByVal S As String) As String
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

[code]....

I want Send a Name like "Arindam" and its return me "m", the last character.but in messagbox return value shows "fasle" I can't under stand why it's showing "False" instead of "m", the last character.

Delegate Not Working Instead Of Lambda Expression

May 14, 2010

I am having a generic ListOf-collection holding the self-created User-object, I can filter for users by using lambda-expression like this:
Dim reviewers As List(Of User) = users.Where(Function(u) u.DvRoleID = 2).ToList

Instead of using the lambda expression I can also write the function and call it as argument like this:
Public Function GetReviewer1(ByVal u As User) As Boolean
If u.DvRoleID = 2 Then
Return True
[Code] .....

Now the question: why can't I create a delegate having the same signature as the GetReviewer1 function and use the delegate as argument inside the where-clause like this:
Delegate Function Criteria(ByVal u As User) As Boolean
Public Function GetReviewer1(ByVal u As User) As Boolean
If u.DvRoleID = 2 Then
[Code] .....
The compiler does not accept the crit delegate as argument.

Getting Exports From Container In MEF (Lambda Expression)

Jun 22, 2012

I am trying to see if the controller class name is the name of the controller name passed in. I think my lambda expression is wrong and that is why it isn't working properly. I am passing in the correct controller names, but the export variable is always null.

Public Function CreateController(requestContext As System.Web.Routing.RequestContext,
controllerName As String)

[Code].....

Lambda Expression And Validity Of Delegates

May 6, 2010

In MSDN documentation defination about lambda expression is "A lambda expression is a function or subroutine without a name that can be used wherever a delegate is valid ". Here validity of delegate is necessery only when we are passing lambda expression as an argument to a method.

[Code]...

Lambda Expression With Ternary Operator In VB?

Feb 26, 2010

Lambda expression with ternary operator in VB?

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Make Lambda Expression Dynamically?

Jul 13, 2011

In Entity Framework I usually do something like:

modelBuilder.Entity(Of Model).HasKey(Function(item As Model) New With {item.PropertyA, item.PropertyB })

to map a composite primary key

I need to write a generic function like[code]....

Use A Function Both Directly And As A Lambda Expression?

Apr 24, 2012

Should I be concerned about the performance of the Compile method here?[code]...

The reason I want the lambda expression is because I want that function to be able to get all the way through LINQ-to-SQL to be converted to SQL. The reason I want the direct version is because I have other code that I want to validate individual serial numbers before submitting changes. And I fear that GetValidSerialNumbers.Contains(serialNumber) will execute a more-complex-than-necesssary query.

Use Lambda Expression Within ASP.NET MVC View Using Program?

Oct 28, 2009

With ASP.NET MVC 1.0, .NET 3.5 and C# you can easily pass a method a lambda expression that will do a "Response.Write" some content when it's executed within the method[code]...

VS 2008 - Convertion Of C# And Lambda Expression To .net

Feb 1, 2010

is there any perfect tool of converting C# and lambda expressions into vb.net code.

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