Lloyd McGhee

Another Standard Deviation Extension for LINQ

Dkultra — Fri, 03 Oct 2008 21:16:00 GMT

Just wanted to post my SDev extension for linq

HopeFully someone will find it helpfull

Happy coding all

Module Module1

<Runtime.CompilerServices.Extension()> _

Function StDev(Of T)(ByVal Values As System.Collections.Generic.IEnumerable(Of T), ByVal selector As Func(Of T, Double))

Return Statistics.StDev(Values.Select(selector).ToList())

End Function

End Module

Public Class Statistics

Public Shared Function StDev(ByVal Values As System.Collections.Generic.List(Of Double))

Dim n = Values.Count()

Dim SigXSquare = (From i In Values Select i * i).Sum()

Dim SigX = Values.Sum()

Dim SigSquareX = SigX * SigX

Dim MySTDev As Double = ((n * SigXSquare) - SigSquareX) / (n * (n - 1))

Dim root = Math.Sqrt(MySTDev)

Return root End Function

End Class

Writing basics for computer people

Dkultra — Wed, 23 Jan 2008 18:30:00 GMT

Friends, we as developers, programmers and all the in betweens need to sharpen our communication skills.

After taking a year of English composition in the distant past, I see numerous examples of posts or articles that could be improved with some basic writing guidelines. The first guideline would be to stop using the singular word you. For example, a post on a forum asks: I’m having rounding problems with SQL Server; a possible answer would be: You should pull back the value as a string and then convert the string value in the code behind. Does this not sound better: a person could pull back the value as a string and then convert the value in the code behind? The difference is that “a person” refers not only to the author of the post but also, the readers of the post. Another approach is to eliminate the reference to who is reading the post and just write the solution such as in the post that this example comes from: http://forums.asp.net/t/1199940.aspx

More Guidelines to come

Happy coding.

Lloyd McGhee

First a thanks

Dkultra — Wed, 23 Jan 2008 18:28:00 GMT

First, I would like to Thank Joe for setting up this Blog since, a great place to share my thoughts and ideas has not presented itself until now.

Lloyd McGhee