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• Entrepreneur Needs Programmers, Architects, or Engineers?

  - by brand-newbie

  Hi guys (Ladies included). I posted on a related site, but THIS is the place to be. I want to build a specialized website. I am an entrepreneur and refining valuations now for venture capitalsists: i.e., determining how much cash I will need. I need help in understanding what human resources I need (i.e., Software Programmers, Architects, Engineers, etc.)??? Trust me, I have read most--if not all--of the threads here on the subject, and I can tell you I am no closer to the answer than ever. Here's my technology problem: The website will include (2) main components: a search engine (web crawler)...and a very large database. The search engine will not be a competitor to google, obviously; however, it "will" require bots to scour the web. The website will be, basically, a statistical database....where users should be able to pull up any statistic from "numerous" fields. Like any entrepreneur with a web-based vision, I'm "hoping" to get 100+ million registered users eventually. However, practically, we will start as small as feasible. As regards the technology (database architecture, servers, etc.), I do want quality, quality, quality. My priorities are speed, and the capaility to be scalable...so that if I "did" get globally large, we could do it without having to re-engineer anything. In other words, I want the back-end and the "infrastructure" to be scalable and professional....with emphasis on quality. I am not an IT professional. Although I've built several Joomla-based websites, I'm just a rookie who's only used minor javascript coding to modify a few plug-ins and components. The business I'm trying to create requires specialization and experts. I want to define the problem and let a capable team create the final product, and I will stay totally hands off. So who do you guys suggest I hire to run this thing? A software engineer? I was thinking I would need a "database engineer," a "systems security engineer", and maybe 2 or 3 "programmers" for the search engine. Also a web designer...and maybe a part-time graphic designer...everyone working under a single software engineer. What do you guys think? Who should I hire?...I REALLY need help from some people in the industry (YOU guys) on this. Is this project do-able in 6 months? If so, how many people will I need? Who exactly needs to head up this thing?...Senior software engineer, an embedded engineer, a CC++ engineer, a java engineer, a database engineer? And do I build this thing is Ruby or Java?

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• Why is django giving me an attribute error when I call _set.all() for its children models?

  - by user1876508

  I have two models defined from django.db import models class Blog(models.Model): title = models.CharField(max_length=144) @property def posts(self): self.Post_set.all() class Post(models.Model): title = models.CharField(max_length=144) text = models.TextField() blog = models.ForeignKey('Blog') but the problem is, when I run shell, and enter >>> blog = Blog(title="My blog") >>> post = Post(title="My first post", text="Here is the main text for my blog post", blog=blog) >>> blog.posts I get the error Traceback (most recent call last): File "<console>", line 1, in <module> File "/home/lucas/Programming/Python/Django/djangorestfun/blog/models.py", line 9, in posts self.Post_set.all() AttributeError: 'Blog' object has no attribute 'Post_set' >>> Now I am having the following problem >>> from blog.models import * >>> blog = Blog(title="gewrhter") >>> blog.save() >>> blog.__dict__ {'_state': <django.db.models.base.ModelState object at 0x259be10>, 'id': 1, 'title': 'gewrhter'} >>> blog._state.__dict__ {'adding': False, 'db': 'default'} >>> post = Post(title="sdhxcvb", text="hdbfdgb", blog=blog) >>> post.save() >>> post.__dict__ {'blog_id': 1, 'title': 'sdhxcvb', 'text': 'hdbfdgb', '_blog_cache': <Blog: Blog object>, '_state': <django.db.models.base.ModelState object at 0x259bed0>, 'id': 1} >>> blog.posts >>> print blog.posts None Second update So I followed your guide, but I am still getting nothing. In addition, blog.posts gives me an error. >>> from blog.models import * >>> blog = Blog(title="asdf") >>> blog.save() >>> post = Post(title="asdf", text="sdxcvb", blog=blog) >>> post.save() >>> blog.posts Traceback (most recent call last): File "<console>", line 1, in <module> AttributeError: 'Blog' object has no attribute 'posts' >>> print blog.all_posts None

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• Asynchronous sockets in C#

  - by IVlad

  I'm confused about the correct way of using asynchronous socket methods in C#. I will refer to these two articles to explain things and ask my questions: MSDN article on asynchronous client sockets and devarticles.com article on socket programming. My question is about the BeginReceive() method. The MSDN article uses these two functions to handle receiving data: private static void Receive(Socket client) { try { // Create the state object. StateObject state = new StateObject(); state.workSocket = client; // Begin receiving the data from the remote device. client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void ReceiveCallback( IAsyncResult ar ) { try { // Retrieve the state object and the client socket // from the asynchronous state object. StateObject state = (StateObject) ar.AsyncState; Socket client = state.workSocket; // Read data from the remote device. int bytesRead = client.EndReceive(ar); if (bytesRead > 0) { // There might be more data, so store the data received so far. state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead)); // Get the rest of the data. client.BeginReceive(state.buffer,0,StateObject.BufferSize,0, new AsyncCallback(ReceiveCallback), state); } else { // All the data has arrived; put it in response. if (state.sb.Length > 1) { response = state.sb.ToString(); } // Signal that all bytes have been received. receiveDone.Set(); } } catch (Exception e) { Console.WriteLine(e.ToString()); } } While the devarticles.com tutorial passes null for the last parameter of the BeginReceive method, and goes on to explain that the last parameter is useful when we're dealing with multiple sockets. Now my questions are: What is the point of passing a state to the BeginReceive method if we're only working with a single socket? Is it to avoid using a class field? It seems like there's little point in doing it, but maybe I'm missing something. How can the state parameter help when dealing with multiple sockets? If I'm calling client.BeginReceive(...), won't all the data be read from the client socket? The devarticles.com tutorial makes it sound like in this call: m_asynResult = m_socClient.BeginReceive (theSocPkt.dataBuffer,0,theSocPkt.dataBuffer.Length, SocketFlags.None,pfnCallBack,theSocPkt); Data will be read from the theSocPkt.thisSocket socket, instead of from the m_socClient socket. In their example the two are one and the same, but what happens if that is not the case? I just don't really see where that last argument is useful or at least how it helps with multiple sockets. If I have multiple sockets, I still need to call BeginReceive on each of them, right?

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• Creating a Blog ruby on Rails - Problem Deleting Comments

  - by bgadoci

  As I always type I am new to rails and programming in general so go easy. Thanks in advance. I have successfully followed the initial tutorial from Ryan Bates on how to build a weblog in 15 minutes. If you don't know this tutorial takes you through creating posts and allowing for comments on those post. It even introduces AJAX through the creating and displaying comments on the posts show.html.erb page. All works great. Here's the hiccup, when Ryan takes you though this tutorial he clears out the comments_controller and only shows the code for creating comments. I am trying to add back the ability to edit and destroy comments. Can't see to get it to work, keeps deleting the actual post not the comment (log shows that I keep sending DELETE request to PostsController). Here is my code: class CommentsController < ApplicationController def create @post = Post.find(params[:post_id]) @comment = @post.comments.create!(params[:comment]) respond_to do |format| format.html { redirect_to @post } format.js end end def destroy @comment = Comment.find(params[:id]) @comment.destroy respond_to do |format| format.html { redirect_to(posts_url) } format.xml { head :ok } end end end /views/posts/show.html.erb <%= render :partial => @post %> <p> <%= link_to 'Edit', edit_post_path (@post) %> | <%= link_to 'Destroy', @post, :method => :delete, :confirm => "Are you sure?" %> | <%= link_to 'See All Posts', posts_path %> </p> <h2>Comments</h2> <div id="comments"> <%= render :partial => @post.comments %> </div> <% remote_form_for [@post, Comment.new] do |f| %> <p> <%= f.label :body, "New Comment" %><br/> <%= f.text_area :body %> </p> <p> <%= f.submit "Add Comment" %></p> <% end %> /views/comments/_comment.html.erb <% div_for comment do %> <p> <strong>Posted <%= time_ago_in_words(comment.created_at) %> ago </strong><br/> <%= h(comment.body) %><br/> <%= link_to 'Destroy', @comments, :method => :delete, :confirm => "Are you sure?" %> </p> <% end %>

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• Time complexity of a sorting algorithm

  - by Passonate Learner

  The two programs below get n integers from file and calculates the sum of ath to bth integers q(number of question) times. I think the upper program has worse time complexity than the lower, but I'm having problems calculating the time complexity of these two algorithms. [input sample] 5 3 5 4 3 2 1 2 3 3 4 2 4 [output sample] 7 5 9 Program 1: #include <stdio.h> FILE *in=fopen("input.txt","r"); FILE *out=fopen("output.txt","w"); int n,q,a,b,sum; int data[1000]; int main() int i,j; fscanf(in,"%d%d",&n,&q); for(i=1;i<=n;i++) fscanf(in,"%d",&data[i]); for i=0;i<q;i++) { fscanf(in,"%d%d",&a,&b); sum=0; for(j=a;j<=b;j++) sum+=data[j]; fprintf(out,"%d\n",sum); } return 0; } Program 2: #include <stdio.h> FILE *in=fopen("input.txt","r"); FILE *out=fopen("output.txt","w"); int n,q,a,b; int data[1000]; int sum[1000]; int main() { int i,j; fscanf(in,"%d%d",&n,&q); for(i=1;i<=n;i++) fscanf(in,"%d",&data[i]); for(i=1;i<=n;i++) sum[i]=sum[i-1]+data[i]; for(i=0;i<q;i++) { fscanf(in,"%d%d",&a,&b); fprintf(out,"%d\n",sum[b]-sum[a-1]); } return 0; } The programs below gets n integers from 1 to m and sorts them. Again, I cannot calculate the time complexity. [input sample] 5 5 2 1 3 4 5 [output sample] 1 2 3 4 5 Program: #include <stdio.h> FILE *in=fopen("input.txt","r") FILE *out=fopen("output.txt","w") int n,m; int data[1000]; int count[1000]; int main() { int i,j; fscanf(in,"%d%d",&n,&m); for(i=0;i<n;i++) { fscanf(in,"%d",&data[i]); count[data[i]]++ } for(i=1;i<=m;i++) { for(j=0;j<count[i];j++) fprintf(out,"%d ",i); } return 0; } It's ironic(or not) that I cannot calculate the time complexity of my own algorithms, but I have passions to learn, so please programming gurus, help me!

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• Gateway Page Between ASP and an ASP.NET Page

  - by ajdams

  I'll admit, I am pretty new with ASP .NET programming and I have been asked to take all our gateway pages (written in classic ASP) and make one universal gateway page to the few C# .NET applications we have (that I wrote). I tried searching here and the web and couldn't find much of anything describing a great way to do this and figured I was either not searching properly or was not properly naming what I am trying to do. I decided to to take one of the main gateway pages we had in classic ASP and use that as a base for my new gateway. Without boring you with a bunch of code I will summarize my gateway in steps and then can take advice/critique from there. EDIT: Basically what I am trying to do is go from a classic ASP page to a ASP .NET page and then back again. EDIT2: If my question is still unclear I am asking if what I have an the right start and if anyone has suggestions as to how this could be better. It can be as generic as need-be, not looking for a specific off-the-shelf code answer. My Gateway page: In the first part of the page I grab session variables and determine if the user is leaving or returning through the gateway: Code (in VB): uid = Request.QueryString("GUID") If uid = "" Then direction = "Leaving" End If ' Gather available user information. userid = Session("lnglrnregid") bankid = Session("strBankid") ' Return location. floor = Request.QueryString("Floor") ' The option chosen will determine if the user continues as SSL or not. ' If they are currently SSL, they should remain if chosen. option1 = Application(bankid & "Option1") If MID(option1, 6, 1) = "1" Then sslHttps = "s" End If Next I enter the uid into a database table (SQL-Server 2005) as a uniqueidentifier field called GUID. I omitted the stored procedure call. Lastly, I use the direction variable to determine if the user is leaving or returning and do redirects from there to the different areas of the site. Code (In VB again): If direction = "Leaving" Then Select Case floor Case "sscat", "ssassign" ' A SkillSoft course Response.Redirect("Some site here") Case "lrcat", "lrassign" ' A LawRoom course Response.Redirect("Some site here") Case Else ' Some other SCORM course like MindLeaders or a custom upload. Response.Redirect("Some site here") End Select Session.Abandon Else ' The only other direction is "Returning" ..... That's about it so far - so like I said, not an expert so any suggestions would be greatly appreciated!

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• practical security ramifications of increasing WCF clock skew to more than an hour

  - by Andrew Patterson

  I have written a WCF service that returns 'semi-private' data concerning peoples name, addresses and phone numbers. By semi-private, I mean that there is a username and password to access the data, and the data is meant to be secured in transit. However, IMHO noone is going to expend any energy trying to obtain the data, as it is mostly available in the public phone book anyway etc. At some level, the security is a bit of security 'theatre' to tick some boxes imposed on us by government entities. The client end of the service is an application which is given out to registered 'users' to run within their own IT setups. We have no control over the IT of the users - and in fact they often tell us to 'go jump' if we put too many requirements on their systems. One problem we have been encountering is numerous users that have system clocks that are not accurate. This can either be caused by a genuine slow/fast clocks, or more than likely a timezone or daylight savings zone error (putting their machine an hour off the 'real' time). A feature of the WCF bindings we are using is that they rely on the notion of time to detect replay attacks etc. <wsHttpBinding> <binding name="normalWsBinding" maxBufferPoolSize="524288" maxReceivedMessageSize="655360"> <reliableSession enabled="false" /> <security mode="Message"> <message clientCredentialType="UserName" negotiateServiceCredential="false" algorithmSuite="Default" establishSecurityContext="false" /> </security> </binding> </wsHttpBinding> The inaccurate client clocks cause security exceptions to be thrown and unhappy users. Other than suggesting users correct their clocks, we know that we can increase the clock skew of the security bindings. http://www.danrigsby.com/blog/index.php/2008/08/26/changing-the-default-clock-skew-in-wcf/ My question is, what are the real practical security ramifications of increasing the skew to say 2 hours? If an attacker can perform some sort of replay attack, why would a clock skew window of 5 minutes be necessarily safer than 2 hours? I presume performing any attack with security mode of 'message' requires more than just capturing some data at a proxy and sending the data back in again to 'replay' the call? In a situation like mine where data is only 'read' by the users, are there indeed any security ramifications at all to allowing 'replay' attacks?

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• how to read input with multiple lines in java

  - by Gandalf StormCrow

  Hi all, Our professor is making us do some basic programming with java, he gaves a website and everything to register and submit our questions, for today I need to do this one example I feel like I'm on the right track but I just can't figure out the rest .. here is the actualy question : **Sample Input:** 10 12 10 14 100 200 **Sample Output:** 2 4 100 And here is what I've got so far : public class Practice { public static int calculateAnswer(String a, String b) { return (Integer.parseInt(b) - Integer.parseInt(a)); } public static void main(String[] args) { System.out.println(calculateAnswer(args[0], args[1])); } } Now I always get the answer 2 because I'm reading the single line, how can I take all lines into account? thank you For some strange reason everytime I want to execute I get this error: C:\sonic>java Practice.class 10 12 Exception in thread "main" java.lang.NoClassDefFoundError: Fact Caused by: java.lang.ClassNotFoundException: Fact.class at java.net.URLClassLoader$1.run(URLClassLoader.java:20 at java.security.AccessController.doPrivileged(Native M at java.net.URLClassLoader.findClass(URLClassLoader.jav at java.lang.ClassLoader.loadClass(ClassLoader.java:307 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher. at java.lang.ClassLoader.loadClass(ClassLoader.java:248 Could not find the main class: Practice.class. Program will exit. Whosever version of answer I use I get this error, what do I do ? However if I run it in eclipse Run as Run Configuration - Program arguments 10 12 10 14 100 200 I get no output EDIT I have made some progress, at first I was getting the compilation error, then runtime error and now I get wrong answer , so can anybody help me what is wrong with this : import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.math.BigInteger; public class Practice { public static BigInteger calculateAnswer(String a, String b) { BigInteger ab = new BigInteger(a); BigInteger bc = new BigInteger(b); return bc.subtract(ab); } public static void main(String[] args) throws IOException { BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in)); String line; while ((line = stdin.readLine()) != null && line.length()!= 0) { String[] input = line.split(" "); if (input.length == 2) { System.out.println(calculateAnswer(input[0], input[1])); } } } }

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• Scheme Formatting Help

  - by Logan

  I've been working on a project for school that takes functions from a class file and turns them into object/classes. The assignment is all about object oriented programming in scheme. My problem however is that my code doesn't format right. The output it gives me whenever I give it a file to pass in wraps the methods of the class in a list, making it so that the class never really gets declared. I can't for the life of me figure out how to get the parenthesis wrapping the method list to remove. I would really appreciate any help. Below is the code and the class file. ;;;; PART1 --- A super-easy set of classes. Just models points and lines. Tests all of the ;; basics of class behavior without touching on anything particularly complex. (class pointInstance (parent:) (constructor_args:) (ivars: (myx 1) (myy 2)) (methods: (getx () myx) (gety () myy) (setx (x) (set! myx x)) (show () (begin (display "[") (display myx) (display ",") (display myy) (display "]"))) )) (require (lib "trace.ss")) ;; Continue reading until you hit the end of the file, all the while ;; building a list with the contents (define load-file (lambda (port) (let ((rec (read port))) (if (eof-object? rec) '() (cons rec (load-file port)))))) ;; Open a port based on a file name using open-input-file (define (load fname) (let ((fport (open-input-file fname))) (load-file fport))) ;(define lis (load "C:\\Users\\Logan\\Desktop\\simpletest.txt")) ;(define lis (load "C:\\Users\\Logan\\Desktop\\complextest.txt")) (define lis (load "C:\\Users\\Logan\\Desktop\\pointinstance.txt")) ;(display (cdaddr (cdddar lis))) (define makeMethodList (lambda (listToMake retList) ;(display listToMake) (cond [(null? listToMake) retList ;(display "The list passed in to parse was null") ] [else (makeMethodList (cdr listToMake) (append retList (list (getMethodLine listToMake)))) ] ) )) ;(trace makeMethodList) ;this works provided you just pass in the function line (define getMethodLine (lambda (functionList) `((eq? (car msg) ,(caar functionList)) ,(caddar functionList)))) (define load-classes (lambda paramList (cond [(null? paramList) (display "Your parameters are null, man.")] [(null? (car paramList))(display "Done creating class definitions.")] [(not (null? (car paramList))) (begin (let* ((className (cadaar paramList)) (classInstanceVars (cdaddr (cddaar paramList))) (classMethodList (cdr (cadddr (cddaar paramList)))) (desiredMethodList (makeMethodList classMethodList '())) ) ;(display "Classname: ") ;(display className) ;(newline)(newline) ;(display "Class Instance Vars: ") ;(display classInstanceVars) ;(newline)(newline) ;(display "Class Method List: ") ;(display classMethodList) ;(newline) ;(display "Desired Method List: ") ;(display desiredMethodList)) ;(newline)(newline) ;---------------------------------------------------- ;do not delete the below code!` `(define ,className (let ,classInstanceVars (lambda msg ;return the function list here (cond ,(makeMethodList classMethodList '()))) )) ;--------------------------------------------------- ))] ) )) (load-classes lis) ;(load-classes lis) ;(load-classes-helper lis) ;(load-classes "simpletest.txt") ;(load-classes "complextest.txt") ;method list ;(display (cdr (cadddr (cddaar <class>))))

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• Opera Mobile, offline web app development, and memory

  - by Jake Krohn

  I'm developing a data collection app for use on a HP iPAQ 211. I'm doing it as an offline web app (go with what you know) using Opera Mobile 9.7 and Google Gears. Being it is an offline app, it is very dependent on Javascript for much of its behavior. I'm using the LocalServer, Database, and Geolocation components of Gears, as well as the JQuery core and a couple of plugins for form validation and other usability tweaks (no jQuery UI). I've tried to be conservative with my programming style and free up or close resources whenever possible, but Opera just slowly dies after about 10-20 minutes of use. The Javascript engine stops responding, pages only half-load, and eventually stop loading completely. I'm guessing it's a resource issue. Quitting and relaunching the browser solves the problem, but only temporarily. The iPAQ ships with 128 MB of RAM, about 85-87 MB of which is available immediately after a reset. With only Opera running, there still remains about 50 MB that is left unused. My questions are thus: Is it possible to get Opera to address this unused RAM? Are there configuration settings in Opera or in the Windows Registry itself that will help improve performance? I know where to tweak, but the descriptions of the opera:config variables that I've found are less than helpful. Is is laughable to ask about memory management and jQuery in the same sentence? If not, does anyone have any suggestions? Finally, are my plans too ambitious, given the platform I have to work with? I know that Gears and Windows Mobile 6 are on their way out, but they (theoretically) suffice for what I need to do. I could ditch them in favor of an iPhone/iPod Touch, Mobile Safari, and HTML5 but I'd like to try to make this work first. I didn't think that Opera was a dog when it comes to JS performance, but perhaps it's worse than I thought. That this motley collection of technologies works at all is a minor miracle, but it needs to be faster and more stable. I appreciate any suggestions.

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• How to read the 3D chart data with directX?

  - by MemoryLeak

  I am reading a open source project, and I found there is a function which read 3D data(let's say a character) from obj file, and draw it . the source code: List<Vertex3f> verts=new List<Vertex3f>(); List<Vertex3f> norms=new List<Vertex3f>(); Groups=new List<ToothGroup>(); //ArrayList ALf=new ArrayList();//faces always part of a group List<Face> faces=new List<Face>(); MemoryStream stream=new MemoryStream(buffer); using(StreamReader sr = new StreamReader(stream)){ String line; Vertex3f vertex; string[] items; string[] subitems; Face face; ToothGroup group=null; while((line = sr.ReadLine()) != null) { if(line.StartsWith("#")//comment || line.StartsWith("mtllib")//material library. We build our own. || line.StartsWith("usemtl")//use material || line.StartsWith("o")) {//object. There's only one object continue; } if(line.StartsWith("v ")) {//vertex items=line.Split(new char[] { ' ' }); vertex=new Vertex3f();//float[3]; if(flipHorizontally) { vertex.X=-Convert.ToSingle(items[1],CultureInfo.InvariantCulture); } else { vertex.X=Convert.ToSingle(items[1],CultureInfo.InvariantCulture); } vertex.Y=Convert.ToSingle(items[2],CultureInfo.InvariantCulture); vertex.Z=Convert.ToSingle(items[3],CultureInfo.InvariantCulture); verts.Add(vertex); continue; } And why it need to read the data manually in directX? As far as I know, in XDA programming, we just need to call a function a load the resource. Is this because it is in DirectX, there is no function to read resource? If yes, then how to prepare the 3D resource ? in XDA we just need to use other software draw the 3D picture and then export. but what should I do in DirectX?

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• Daylight saving time and Timezone best practices

  - by Oded

  I am hoping to make this question and the answers to it the definitive guide to dealing with daylight saving time, in particular for dealing with the actual change overs. If you have anything to add, please do Many systems are dependent on keeping accurate time, the problem is with changes to time due to daylight savings - moving the clock forward or backwards. For instance, one has business rules in an order taking system that depend on the time of the order - if the clock changes, the rules might not be as clear. How should the time of the order be persisted? There is of course an endless number of scenarios - this one is simply an illustrative one. How have you dealt with the daylight saving issue? What assumptions are part of your solution? (looking for context here) As important, if not more so: What did you try that did not work? Why did it not work? I would be interested in programming, OS, data persistence and other pertinent aspects of the issue. General answers are great, but I would also like to see details especially if they are only available on one platform. Summary of answers and other data: (please add yours) Do: Always persist time according to a unified standard that is not affected by daylight savings. GMT and UTC have been mentioned by different people. Include the local time offset (including DST offset) in stored timestamps. Remember that DST offsets are not always an integer number of hours (e.g. Indian Standard Time is UTC+05:30). If using Java, use JodaTime. - http://joda-time.sourceforge.net/ Create a table TZOffsets with three columns: RegionClassId, StartDateTime, and OffsetMinutes (int, in minutes). See answer Check if your DBMS needs to be shutdown during transition. Business rules should always work on civil time. Internally, keep timestamps in something like civil-time-seconds-from-epoch. See answer Only convert to local times at the last possible moment. Don't: Do not use javascript date and time calculations in web apps unless you ABSOLUTELY have to. Testing: When testing make sure you test countries in the Western and Eastern hemispheres, with both DST in progress and not and a country that does not use DST (6 in total). Reference: Olson database, aka Tz_database - ftp://elsie.nci.nih.gov/pub Sources for Time Zone and DST - http://www.twinsun.com/tz/tz-link.htm ISO format (ISO 8601) - http://en.wikipedia.org/wiki/ISO_8601 Mapping between Olson database and Windows TimeZone Ids, from the Unicode Consortium - http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/windows_tzid.html TimeZone page on WikiPedia - http://en.wikipedia.org/wiki/Tz_database StackOverflow questions tagged dst - http://stackoverflow.com/questions/tagged/dst StackOverflow questions tagged timezone - http://stackoverflow.com/questions/tagged/timezone Other: Lobby your representative to end the abomination that is DST. We can always hope...

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• How to create a Uri instance parsed with GenericUriParserOptions.DontCompressPath

  - by Andrew Arnott

  When the .NET System.Uri class parses strings it performs some normalization on the input, such as lower-casing the scheme and hostname. It also trims trailing periods from each path segment. This latter feature is fatal to OpenID applications because some OpenIDs (like those issued from Yahoo) include base64 encoded path segments which may end with a period. How can I disable this period-trimming behavior of the Uri class? Registering my own scheme using UriParser.Register with a parser initialized with GenericUriParserOptions.DontCompressPath avoids the period trimming, and some other operations that are also undesirable for OpenID. But I cannot register a new parser for existing schemes like HTTP and HTTPS, which I must do for OpenIDs. Another approach I tried was registering my own new scheme, and programming the custom parser to change the scheme back to the standard HTTP(s) schemes as part of parsing: public class MyUriParser : GenericUriParser { private string actualScheme; public MyUriParser(string actualScheme) : base(GenericUriParserOptions.DontCompressPath) { this.actualScheme = actualScheme.ToLowerInvariant(); } protected override string GetComponents(Uri uri, UriComponents components, UriFormat format) { string result = base.GetComponents(uri, components, format); // Substitute our actual desired scheme in the string if it's in there. if ((components & UriComponents.Scheme) != 0) { string registeredScheme = base.GetComponents(uri, UriComponents.Scheme, format); result = this.actualScheme + result.Substring(registeredScheme.Length); } return result; } } class Program { static void Main(string[] args) { UriParser.Register(new MyUriParser("http"), "httpx", 80); UriParser.Register(new MyUriParser("https"), "httpsx", 443); Uri z = new Uri("httpsx://me.yahoo.com/b./c.#adf"); var req = (HttpWebRequest)WebRequest.Create(z); req.GetResponse(); } } This actually almost works. The Uri instance reports https instead of httpsx everywhere -- except the Uri.Scheme property itself. That's a problem when you pass this Uri instance to the HttpWebRequest to send a request to this address. Apparently it checks the Scheme property and doesn't recognize it as 'https' because it just sends plaintext to the 443 port instead of SSL. I'm happy for any solution that: Preserves trailing periods in path segments in Uri.Path Includes these periods in outgoing HTTP requests. Ideally works with under ASP.NET medium trust (but not absolutely necessary).

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• Downloading Python 2.5.4 (from official website) in order to install it

  - by brilliant

  I was quite hesitant about whether I should post this question here on "StackOverflow" or on "SuperUser", but finally decided to post it here as Python is more a programming language rather than a piece of software. I've been recently using Python 2.5.4 that is installed on my computer, but at the moment I am not at home (and won't be for about two weeks from now), so I need to install the same version of Python on another computer. This computer has Windows XP installed – just like the one that I have at home. The reason why I need Python 2.5.4 is because I am using “Google App Engine”, and I was told that it only supports Python 2.5 However, when I went to the official Python page for the download, I discovered that certain things have changed, and I don’t quite remember where exactly from that site I had downloaded Python 2.5.4 on my computer at home. I found this page: http://www.python.org/download/releases/2.5.4/ Here is how it looks: (If you can’t see it here, please check it out at this address: http://brad.cwahi.net/some_pictures/python_page.jpg ) A few things here are not clear to me. It says: “For x86 processors: python-2.5.4.msi For Win64-Itanium users: python-2.5.4.ia64.msi For Win64-AMD64 users: python-2.5.4.amd64.msi” First of all, I don’t know what processor I am using – whether mine is “x86” or not; and also, I don’t know whether I am an “Win64-Itanium” or an “Win64-AMD64” user. Are Itanium and AMD64 also processors? Later it says: “Windows XP and later already have MSI; many older machines will already have MSI installed.” I guess, it is my case, but then I am totally puzzled as to which link I should click as it seems now that I don’t need those three previous links (as MSI is already installed on Windows XP), but there is no fourth link provided for those who use “Windows XP” or older machines. Of course, there are these words after that: “Windows users may also be interested in Mark Hammond's win32all package, available from Sourceforge.” but it seems to me that it is something additional rather than the main file. So, my question is simple: Where in the official Python website I can download Python 2.5.4, precisely, which link I should click?

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• From a 3D modeler to an iPhone app - what are best practices?

  - by bonkey

  I am quite new in 3D programming on iPhone and I would like to ask for hints about organizing a work between designers and programmers on that platform. Most of all: what kind of tools, libraries or plugins cooperate the best on both sides. Although I consider the question as looking for general best-practices advice I would like to find a solution for my current situation which I describe further, too. I've already done some research and found following libraries: SIO2 Khronos OpenGL ES 1.x SDK for PowerVR MBX Unity3D Oolong Game Engine I've checked modellers or plugins to them giving output formats readable by those tools: obj2opengl Wavefront OBJ to plain header file converter Blender with SIO2 exporter iphonewavefrontloader Cheetah3D PVRGeoPOD for 3DS / Maya Unfortunately I still have no clear vision how to combine any of that tools to get a desinger's work in an application. I look for a way of getting it in the most possible complete way: models, lights, scenes, textures, maybe some simple animations (but rather no game-like physics), but I still got nothing. And here comes my situation: I would like to find right way to present few (but quite complicated) models from a single scene. The designers mostly use 3DS Max 9, sometimes 10 (which partly prevents using PVRGeoPOD) and are rather reluctant to switch to something else but if there's no other choice I suppose it would be possible. The basic rule I've already found in some places "use Wavefront OBJ" not always works. I haven't got any acceptable results with production files, actually. The only things worked fine were some mere examples. Some of my models did imported incomplete, sometimes exporters hung or generated enormous files not really useful on an iPhone, sometimes enabling textures (with GL_TEXTURE_2D) just crashed an app. I know it might be a problem with too complicated models or my mistakes coming from inexeperience but I am not able to find any guidelines for that process to have streamlined cooperation with designers. I am even willing to write some things from scratch in pure OpenGL-ES if it's necessary, but I would like to avoid what might be avoided and get the most from the model files. The best would be the effect I saw on some SIO2 tutorials: export, build & go. But at that moment I've got only "import, wrong", "import, where are textures?", "import, that almost looks fine, export, hang" and so on... Is it really so much frustrating or I am just missed something obvious? Can anybody share his/her experience in that field and tell what kind of software uses for "making things happen"?

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• Scared of Calculus - Required to pass Differential Calculus as part of my Computer science major

  - by ke3pup

  Hi guys I'm finishing my Computer science degree in university but my fear of maths (lack of background knowledge) made me to leave all my maths units til' the very end which is now. i either take them on and pass or have to give up. I've passed all my programming units easily but knowing my poor maths skills won't do i've been staying clear of the maths units. I have to pass Differential Calculus and Linear Algebra first. With a help of book named "Linear Algebra: A Modern Introduction" i'm finding myself on track and i think i can pass the Linear Algebra unit. But with differential calculus i can't find a book to help me. They're either too advanced or just too simple for what i have to learn. The things i'm required to know for this units are: Set notation, the real number line, Complex numbers in cartesian form. Complex plane, modulus. Complex numbers in polar form. De Moivre’s Theorem. Complex powers and nth roots. Definition of ei? and ez for z complex. Applications to trigonometry. Revision of domain and range of a function Working in R3. Curves and surfaces. Functions of 2 variables. Level curves.Partial derivatives and tangent planes. The derivative as a difference quotient. Geometric significance of the derivative. Discussion of limit. Higher order partial derivatives. Limits of f(x,y). Continuity. Maxima and minima of f(x,y). The chain rule. Implicit differentiation. Directional derivatives and the gradient. Limit laws, l’Hoˆpital’s rule, composition law. Definition of sinh and cosh and their inverses. Taylor polynomials. The remainder term. Taylor series. Is there a book to help me get on track with the above? Being a student i can't buy too many books hence why i'm looking for a book that covers topics I need to know. The University library has a fairly limited collection which i took as loan but didn't find useful as it was too complex.

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• Using in app purchase to unlock features vs. using free & paid app versions for iPhone

  - by yabada

  I have an app that I was going to release as a free (lite) version with some of the total functionality and a paid full version with advanced functionality. Now, with in app purchase for free apps I am thinking of going that route with the ability to unlock features as needed. I'm not talking about a trial version that expires.I want people to be able to try out the app and get an idea of the interface and functionality before deciding to purchase the full functionality of each major section of the app, basically. Here's an analogy of what my app would be like. Let's say you have a cooking app that teaches you to cook in different styles. There could be major section for French, Italian, and Chinese. Each section could have some rudiments unlocked in the free app so users can see the UI and basics of the functionality. Then, the user could decide to purchase each major section (or not) individually with in app purchase or buy the full versioned app (with the free/paid model). One concern I have with offering a free app with in app purchase would be with feedback. I would be very clear in my description in the app store that there is in app purchase for full features but I'm worried that less serious users could/would leave negative feedback. I suppose that's always a risk but curious about any experience with this. It also seems that it could be a whole lot more complicated keeping track of what portions of the app are locked and unlocked with in app purchase. I know I'd have to have all the code for the full functionality and "lock" the portions that haven't been purchased. How do people usually lock portions of their code? I'm not talking about the process of purchasing (I've read the In App Purchase Programming Guide) but after the purchase has been made. Would I just keep track of what the user has purchased and put conditionals on the sections that are initially locked? Or is there another way to do this as well? My instinct is for the in app purchase (particularly since users could purchase the major sections that they want individually).

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• json problems with making a ruby on rails application

  - by Prince Merdz

  So I'm using Bitnami to learn Ruby on Rails. I have also previously tried the manual installation for ruby and rails and was met by the same problem so I thought I should try first the easy package deal of Bitnami. Anyway my problem with json is that it causes the bundle install to fail. First the auto bundle install that rails new does fails because of an ssl error. Which is easily solved by changing the source in the gemfile which is https to http. However when I try to bundle install it does another error when it tries to install json. C:\RubyStack-3.2.7-0\projects\testing>bundle install Fetching gem metadata from http://rubygems.org/......... Using rake (0.9.2.2) Using i18n (0.6.0) Using multi_json (1.3.6) Installing activesupport (3.2.8) Using builder (3.0.0) Installing activemodel (3.2.8) Using erubis (2.7.0) Using journey (1.0.4) Using rack (1.4.1) Using rack-cache (1.2) Using rack-test (0.6.1) Using hike (1.2.1) Using tilt (1.3.3) Using sprockets (2.1.3) Installing actionpack (3.2.8) Using mime-types (1.19) Using polyglot (0.3.3) Using treetop (1.4.10) Using mail (2.4.4) Installing actionmailer (3.2.8) Using arel (3.0.2) Using tzinfo (0.3.33) Installing activerecord (3.2.8) Installing activeresource (3.2.8) Using bundler (1.1.5) Using coffee-script-source (1.3.3) Using execjs (1.4.0) Using coffee-script (2.2.0) Using rack-ssl (1.3.2) Installing json (1.7.5) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension . C:/RUBYST~1.7-0/ruby/bin/ruby.exe extconf.rb creating Makefile make 0 [main] echo 5244 open_stackdumpfile: Dumping stack trace to echo.exe.sta ckdump make: *** [generator-i386-mingw32.def] Error 5 Gem files will remain installed in C:/RUBYST~1.7-0/ruby/lib/ruby/gems/1.9.1/gems /json-1.7.5 for inspection. Results logged to C:/RUBYST~1.7-0/ruby/lib/ruby/gems/1.9.1/gems/json-1.7.5/ext/j son/ext/generator/gem_make.out An error occured while installing json (1.7.5), and Bundler cannot continue. Make sure that `gem install json -v '1.7.5'` succeeds before bundling. This is the gem_make.out file it produces after trying to install json (btw windows also produces an error that echo.exe has stopped working while running the gem install json) C:/RUBYST~1.7-0/ruby/bin/ruby.exe extconf.rb creating Makefile make 0 [main] echo 5244 open_stackdumpfile: Dumping stack trace to echo.exe.stackdump make: *** [generator-i386-mingw32.def] Error 5 I can't even start learning ror for the setup is already a huge pain. (btw I have no prior experience with web frameworks, just desktop programming). help?

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• Is Ogre's use of Exceptions a good way of using them?

  - by identitycrisisuk

  I've managed to get through my C++ game programming career so far virtually never touching exceptions but recently I've been working on a project with the Ogre engine and I'm trying to learn properly. I've found a lot of good questions and answers here on the general usage of C++ exceptions but I'd like to get some outside opinions from here on whether Ogre's usage is good and how best to work with them. To start with, quoting from Ogre's documentation of it's own Exception class: OGRE never uses return values to indicate errors. Instead, if an error occurs, an exception is thrown, and this is the object that encapsulates the detail of the problem. The application using OGRE should always ensure that the exceptions are caught, so all OGRE engine functions should occur within a try{} catch(Ogre::Exception& e) {} block. Really? Every single Ogre function could throw an exception and be wrapped in a try/catch block? At present this is handled in our usage of it by a try/catch in main that will show a message box with the exception description before exiting. This can be a bit awkward for debugging though as you don't get a stack trace, just the function that threw the error - more important is the function from our code that called the Ogre function. If it was an assert in Ogre code then it would go straight to the code in the debugger and I'd be able to find out what's going on much easier - I don't know if I'm missing something that would allow me to debug exceptions already? I'm starting to add a few more try/catch blocks in our code now, generally thinking about whether it matters if the Ogre function throws an exception. If it's something that will stop everything working then let the main try/catch handle it and exit the program. If it's not of great importance then catch it just after the function call and let the program continue. One recent example of this was building up a vector of the vertex/fragment program parameters for materials applied to an entity - if a material didn't have any parameters then it would throw an exception, which I caught and then ignored as it didn't need to add to my list of parameters. Does this seem like a reasonable way of dealing with things? Any specific advice for working with Ogre is much appreciated.

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• Personal Project - Next practical language/tech to learn

  - by Paul Nathan

  I'm working on a personal project doing some finance analysis. It's a totally new field for me, and I'm really having fun with it so far, plus working in the high-level language arena is a great break from my embedded systems daytime work. I have a MySQL backend on a non-local server with a pile of stock data. My task now is to do some analysis of the stocks and produce something approximating a useful result. There are a couple technical difficulties. (1) I have a lot of records. To be precise, I believe I'm near 100K records right now, and this number grows by 6.1K each weekday. I need to create a way to rummage through these fields and do data analysis - based on a given computation, go look at this other set. Fine and dandy, nothing too outre. But this means I could really use a straightforward API for talking to MySQL. (2) Ideally, it runs on OS X 10.4.11. No Windows/Linux machine at home. (3) I can use PHP, C++, Perl, etc. I even have an R installation. I'm pretty flexible with stuff, so long as it runs on OS X. (Lots of options here, pick water, H20, or dihydrogen monoxide ;-) ) (4)Lack of hassle. While I like clever and fun ways of doing things, I'm trying to get some analysis done, not spend ten hours doing installation work and scratching my head figuring out a theoretical syntax question needed to spout out "hello world". What's the question? I'd like to dig into something different than my usual PHP/C++/C toolset. I'm looking for recommendations for languages/technologies that will assist me and meet the above requirements. In particular, I've heard a lot of buzz about F# and Python on SO. I've used CLISP for small problems before, and kinda liked it. I'm seeking opinions about those in particular. edit:since I rent the DB server and have a limited amount of CPU time online, I'm trying to do the analysis on a local machine.

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• What do you expect from a package manager for Emacs

  - by tarsius

  Although several hundred Emacs Lisp libraries exist GNU Emacs does not have an (internal) package manager. I guess that most users would agree that it is currently rather inconvenient to find, install and especially keep up-to-date Emacs Lisp libraries. These pages make life a bit easier Emacs Lisp List - Problem: I see dead people (links). Emacswiki - Problem: May contain traces of nuts (malicious code). These are some package managers XEmacs package manager package.el - ELPA pases install.el install-elisp.el plugin.el use-package.el jem-pkg.el epkg/elm - the one I am working. And this are some packages that provide functionality that might be useful in a package manager ell.el - Browse the Emacs Lisp List genauto.el - helps generate autoloads for your elisp packages date-calc.el - date calculation and parsing routines strptime.el - partial implementation of POSIX date and time parsing wikirel.el - Visit relevant pages on the Emacs Wiki loadhist.el, lib-requires.el, elisp-depend.el - Commands to list Emacs Lisp library dependencies. project-root.el - Define a project root and take actions based upon it So I would like to know from you what you consider important/unimportant/supplementary... in a package manager for Emacs. Some ideas Many packages (incorporate the Emacs Lisp List and other lists of libraries). Only packages that have been tested. Support for more than one package archive (so people can choose between many/tested packages). Dependency calculated based on required features only. Dependencies take particular versions into account. Only use versions that have been released upstream. Use versions from version control systems if available. Packages are categorized. Packages can be uninstalled and updated not only installed. Support creating fork of upstream version of packages. Support publishing these forks. Support choosing a fork. After installation packages are activated. Generate autoloads. Integration with Emacswiki (see wikirel.el). Users can tag, comment ... packages and share that information. Only FSF-assigned/GPL/FOSS software or don't care about license. Package manager should be integrated in Emacs. Support contacting author. Lots of metadata. Suggest alternatives before installing a particular package. Some discussions about the subject at hand emacs-devel 20080801 comp.emacs 20021121 RationalElispPackaging I am hoping for these kinds of answers Pointers to more implementations, discussions etc. Lengthy descriptions of a set of features that make up your ideal package manager. Descriptions of one particular disired/undisired feature. This has the advantage that the regular voting mechanism allows us to see what features are most welcomed. Feel free to elaborate on my ideas from above. Surprise me.

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• Fixed point math in c#?

  - by x4000

  Hi there, I was wondering if anyone here knows of any good resources for fixed point math in c#? I've seen things like this (http://2ddev.72dpiarmy.com/viewtopic.php?id=156) and this (http://stackoverflow.com/questions/79677/whats-the-best-way-to-do-fixed-point-math), and a number of discussions about whether decimal is really fixed point or actually floating point (update: responders have confirmed that it's definitely floating point), but I haven't seen a solid C# library for things like calculating cosine and sine. My needs are simple -- I need the basic operators, plus cosine, sine, arctan2, PI... I think that's about it. Maybe sqrt. I'm programming a 2D RTS game, which I have largely working, but the unit movement when using floating-point math (doubles) has very small inaccuracies over time (10-30 minutes) across multiple machines, leading to desyncs. This is presently only between a 32 bit OS and a 64 bit OS, all the 32 bit machines seem to stay in sync without issue, which is what makes me think this is a floating point issue. I was aware from this as a possible issue from the outset, and so have limited my use of non-integer position math as much as possible, but for smooth diagonal movement at varying speeds I'm calculating the angle between points in radians, then getting the x and y components of movement with sin and cos. That's the main issue. I'm also doing some calculations for line segment intersections, line-circle intersections, circle-rect intersections, etc, that also probably need to move from floating-point to fixed-point to avoid cross-machine issues. If there's something open source in Java or VB or another comparable language, I could probably convert the code for my uses. The main priority for me is accuracy, although I'd like as little speed loss over present performance as possible. This whole fixed point math thing is very new to me, and I'm surprised by how little practical information on it there is on google -- most stuff seems to be either theory or dense C++ header files. Anything you could do to point me in the right direction is much appreciated; if I can get this working, I plan to open-source the math functions I put together so that there will be a resource for other C# programmers out there. UPDATE: I could definitely make a cosine/sine lookup table work for my purposes, but I don't think that would work for arctan2, since I'd need to generate a table with about 64,000x64,000 entries (yikes). If you know any programmatic explanations of efficient ways to calculate things like arctan2, that would be awesome. My math background is all right, but the advanced formulas and traditional math notation are very difficult for me to translate into code.

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• The most efficient method of drawing multiple quads in OpenGL

  - by CPatton

  I'm not very keen with OpenGL and I was wondering if someone could give me some insight on this. I'm a 'seasoned' programmer, I've read the redbook about VBOs and the like, but I was wondering from a more experienced person about the best/most efficient way of achieving this. I've been producing this 2d tile-based game engine to be used in several projects. I have a class called "ScreenObject" which is mainly composed of a Dictionary<Point, Tile> The Point key is to show where to render the Tile on the screen, and the Tile contains one or more textures to be drawn at that point. This ScreenObject is where the tiles will be modified, deleted, added, etc.. My original method of drawing the tiles in the testing I've done was to iterate through the ScreenObject and draw each quad at each location separately. From what I've read, this is a massive waste of resources. It wasn't horribly slow in the testing, but after I've completed the animation classes and effect classes, I'm sure it would be extremely slow. And one last thing, if you wouldn't mind.. As I said before, the Tile class can contain multiple textures to be drawn at the Point location on the screen. I recognize possibly two options for me here. Either add a quad at that location for each texture to be drawn, or, somehow.. use a multiple texture for the same quad (if it's possible). Even if each tile contained one texture only, that would be 64 quads to be drawn on the screen. Most of the tiles will contain 2-5 textures, so the number of total quads would increase dramatically with this method. Would it be feasible to add a quad for each new texture, or am I ignoring a better way to do this? Just need some help understanding this if you don't mind :) I've tried to be as concise as possible, and I'd greatly appreciate any responses.. and even some criticism. Programming is often a learning process and one who develops seems to never stops learning. Thanks for your time.

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• iGoogle Stack Overflow Gadget [closed]

  - by Charango

  Since SO's question database is becoming an excellent first point of call for finding answers to coding problems, some people (like me) might like to be able to fire up searches from their iGoogle home page, among the other searches you might launch from there. I've created a very simple gadget to do this, and put the source below. My hope is that this might provide a foundation on which community members with better ideas for performing this function, or ideas for enhancing it, can update it. Perhaps we could make it configurable to search via a site scope search from Google and / or a question search, for instance. I've hosted and registered this first version but if anyone makes changes and can host a new version / new pics elsewhere, please feel free. <?xml version="1.0" encoding="UTF-8"?> <Module> <ModulePrefs title="Stack Overflow Search" author="Community Wiki" author_email="[email protected]" author_affiliation="Stack Overflow" author_location="The Internet" author_aboutme="All sorts" author_link="http://stackoverflow.com" author_quote="Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law." description="Stack Overflow is rapidly becoming one of the best resources for finding answers to your programming questions. This gadget adds a question search box to your iGoogle homepage" screenshot="http://arkios-solutions.com/misc/sogadget/SOGadget.png" thumbnail="http://arkios-solutions.com/misc/sogadget/SOGadget_Thumbnail.png" singleton="true" title_url="http://stackoverflow.com" /> <Content type="html"><![CDATA[ <img src="http://i.stackoverflow.com/Content/Img/stackoverflow-logo-250.png" alt="Stackoverflow Logo"/> <div style="font-family:arial;font-size:0.8em;"> This gadget allows you to search the Stack Overflow question database. </div> <form name='SOQueryForm' action="http://stackoverflow.com/search" method="get" target="new"> <p>Your question: <input type='text' size='34' name='q' /></p> <p><input type='submit' value='Go' /></p> </form> ]]> </Content> </Module> The source / installable gadget xml are also hosted here.

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• Calculating multiple column average in SQLite3

  - by Benjamin Oakes

  I need to average some values in a row-wise fashion, rather than a column-wise fashion. (If I were doing a column-wise average, I could just use avg()). My specific application of this requires me ignore NULLs in averaging. It's pretty straightforward logic, but seems awfully difficult to do in SQL. Is there an elegant way of doing my calculation? I'm using SQLite3, for what it's worth. Details If you need more details, here's an illustration: I have a a table with a survey: | q1 | q2 | q3 | ... | q144 | |----|-------|-------|-----|------| | 1 | 3 | 7 | ... | 2 | | 4 | 2 | NULL | ... | 1 | | 5 | NULL | 2 | ... | 3 | (Those are just some example values and simple column names. The valid values are 1 through 7 and NULL.) I need to calculate some averages like so: q7 + q33 + q38 + q40 + ... + q119 / 11 as domain_score_1 q10 + q11 + q34 + q35 + ... + q140 / 13 as domain_score_2 ... q2 + q5 + q13 + q25 + ... + q122 / 12 as domain_score_14 ...but i need to pull out the nulls and average based on the non-nulls. So, for domain_score_1 (which has 11 items), I would need to do: Input: 3, 5, NULL, 7, 2, NULL, 3, 1, 5, NULL, 1 (3 + 5 + 7 + 2 + 3 + 1 + 5 + 1) / (11 - 3) 27 / 8 3.375 A simple algorithm I'm considering is: Input: 3, 5, NULL, 7, 2, NULL, 3, 1, 5, NULL, 1 Coalesce each value to 0 if NULL: 3, 5, 0, 7, 2, 0, 3, 1, 5, 0, 1 Sum: 27 Get the number of non-zeros by converting values 0 to 1 and sum: 3, 5, 0, 7, 2, 0, 3, 1, 5, 0, 1 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1 8 Divide those two numbers 27 / 8 3.375 But that seems like a lot more programming than this should take. Is there an elegant way of doing this that I'm not aware of? Update: Unless I'm misunderstanding something, avg() won't work for this. Example of what I would want to do: select avg(q7, q33, q38, ..., q119) from survey; Output: SQL error near line 3: wrong number of arguments to function avg()

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