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• C# regex: negative lookahead fails with the single line option

  - by Sylverdrag

  I am trying to figure out why a regex with negative look ahead fails when the "single line" option is turned on. Example (simplified): <source>Test 1</source> <source>Test 2</source> <target>Result 2</target> <source>Test 3</source> This: <source>(?!.*<source>)(.*?)</source>(?!\s*<target) will fail if the single line option is on, and will work if the single line option is off. For instance, this works (disables the single line option): (?-s:<source>(?!.*<source>)(.*?)</source>(?!\s*<target)) My understanding is that the single line mode simply allows the dot "." to match new lines, and I don't see why it would affect the expression above. Can anyone explain what I am missing here?

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• How extension methods work in background ?

  - by Freshblood

  I am just cuirous about behind of extension method mechanism.Some questions and answer appear in my mind. MyClass.OrderBy(x=>x.a).OrderBy(x=>x.b); I was guessing that mechanism was first orderby method works and order them by a member then returns sorted items in IEnumarable interface then next Orderby method of IEnumarable Order them for b paramater.But i am wrong when i look at this linq query. MyClass.Orderby(x=>x.a).ThenOrderBy(x=>x.b); this is slightly different and tells me that i am wrong.Because this is not ordering by a then b and not possible to have such result if i was right.This get me confuse enough... Similiar structure is possible to write withot extension methods as first query but second is not possible.This prove i am wrong . Can u explain it ?

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• How to register data for validation using RegisterForEventValidation in asp.net

  - by rocksolid

  I would like to know the method of using RegisterForEventValidation in asp.net My problem is this. If I enable eventvalidation, then changing the controls using javascript and then posting the information back to the server later on throws up an error. But If I disable event validation, the data present/selected in the controls is not available in the event handlers in code behind. So, how should one resolve such issues? Also, are there are any good articles that explain the issue and a resolution in detail? Tried googling. Came across many articles. But nothing that matched my expectations. Thanks!

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• What type of websites does memcached speed up

  - by Saif Bechan

  I have read this article about 400% boost of your website. This is done by a combination of nginx and memcached. The how-to part of this website is quite good, but i mis the part where it says to what types of websites this applies. I know nginx is a http engine, I need no explanation for that. I thought memcached had something to do with caching database result. However i don't understand what this has to do with the http request, can someone please explain that to me. Another question I have is for what types of websites is this used. I have a website where the important part of the website consist of data that changes often. Often being minutes. Will this method still apply to me, or should I just stick with the basic boring setup of apache and nothing else.

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• Understanding The Convolution Matrix

  - by Ryan Naddy

  I am learning about the Convolution Matrix, and I understand how they work, but I don't understand how to know before hand what the output of a Matrix will look like. For example lets say I want to add a blur to an image, I could guess 10,000+ different combinations of numbers before I get the correct one. I do know though that this formula will give me a blur effect, but I have no idea why. float[] sharpen = new float[] { 1/9f, 1/9f, 1/9f, 1/9f, 1/9f, 1/9f, 1/9f, 1/9f, 1/9f }; Can anyone either explain to me how this works or point me to some article, that explains this? I would like to know before hand what a possible output of the matrix will be without guessing. Basically I would like to know why do we put that number in the filed, and why not some other number?

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• I have a problem with the following Java code

  - by Sanjeev

  public class b { public static void main(String[] args) { byte b = 1; long l = 127; // b = b + l; // 1 if I try this then it does not compile b += l; // 2 if I try this then it does compile System.out.println(b); } } I am using this code but I have problem: I don't understand why b=b+l; is not compiling but if I write b+=l; then it compiles and runs. Please explain why this happens.

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• iPhone Web Appication deployment and distribution process

  - by yakub_moriss

  Hi,All --I haven't develop any iPhone Web Application ever...so i am little bit confuse about that. --I want to build a Web Application for iPhone which will be made using(CSS+JavaScript). --I read some where that no approval is required for iPhone Web Application. is it correct ? --And if i have made my iPhone Web Application (using CSS+JavaScript)and uploaded at my server. --and if i want to open it in UIWebView using iPhone SDK simply... --is this Application is valid for iPhone Web Application portal https://adcweb.apple.com/iphone/index.php or not ? --how can end users get the Application on their iPhone after submiting to the portal... --can any one explain me the whole process of iPhone Web Application deployment and distribution process ? Thanks in advance...

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• c# Generic overloaded method dispatching ambiguous

  - by sebgod

  Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

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• PHP and MySQLi close()

  - by Theopile

  Hello all. I am new to mysql and php, but am attempting to make my own cms to help make managing my websites easier. Can someone explain the mysqli's close() function. 1)Is it nesseccary? 2)What exactly does it do? 3)I heard that after php runs its script that it closes the connection, is that true? 4)Lastly, is there a security issue when not closing your connection to the database? Thanks

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• How to get the "#" symbol in the :id into the redirect_to method in Rails

  - by Matthias Günther

  Hello, this is a silly questions but I don't understand, why rails isn't evaluating my string as expected. Here is my problem: I want to redirect to an url in the form ~/:controller/index/#_76 redirect_to :action => "index", :id => '#_76' But I'm getting the url in the form: ~/:controller/index/%25_76 and so my anchor for linking to a certain place in the website isn't working. Can someone please explain me, why rails makes this rendering? I think this hase something to do with url encoding. Again thanks for your help, I'm learning every day a little bit more about rails :).

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• Initializing structs in C++

  - by Neil Butterworth

  As an addendum to this question, what is going on here: #include <string> using namespace std; struct A { string s; }; int main() { A a = {0}; } Obviously, you can't set a std::string to zero. Can someone provide an explanation (backed with references to the C++ Standard, please) about what is actually supposed to happen here? And then explain for example): int main() { A a = {42}; } Are either of these well-defined? Once again an embarrassing question for me - I always give my structs constructors, so the issue has never arisen before.

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• PHP Modify Array

  - by Ozzy

  Hi all, I have the following array: array(a, a, a, b, b, c, c, c, c, d, d); When I loop through it and echo it, the result is: a a a b b c c c c d d How ever I want to echo it in such a way that it displays: a b c d a b c d a c c Here is the array in a grid to better explain what im trying to achieve Current a a a b b c c c c d d What im tryin to do a b c d a b c d a c c How would I do this?

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• CInternetSession::OpenURL exception if headers are defined. Works fine if not. Why?

  - by Jesse

  Trying to log the application version details in our weblogs using the headers: Should be a one liner..but for some reason whenever I specify anything but NULL for the headers it causes an exception (InternetOpenUrl() call returns NULL) - anyone able to explain why? CInternetSession internet; CHttpFile * pHttpFile; CString headers;// = APPLICATION_SUITE_NAME; DWORD dwHeadersLength = -1; headers.Format("%s %s %s\n",APPLICATION_SUITE_NAME,SHORT_APPLICATION_VERSION,BUILDNO_STR); pHttpFile =(CHttpFile *) internet.OpenURL(lpszURL, 1, INTERNET_FLAG_TRANSFER_ASCII|INTERNET_FLAG_DONT_CACHE, headers, dwHeadersLength); Without the headers, dwHeadersLength parameter (eg. pass in NULL,-1) then it goes through fine and I see the request come through to our website. But why does it fail if I pass in custom headers?

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• How to use DML on Oracle temporary table without generating much undo log

  - by Sambath

  Hi, Using an Oracle temporary table does not generate much redo log as a normal table. However, the undo log is still generated. Thus, how can I write insert, update, or delete statement on a temporary table but Oracle will not generate undo log or generate as little as possible? Moreover, using /+append/ in the insert statement will generate little undo log. Am I correct? If not, could anyone explain me about using the hint /+append/? INSERT /*+APPEND*/ INTO table1(...) VALUES(...); Thank you.

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• When to use Version Control?

  - by user156814

  I am a lone developer, developing Web Sites/Apps in PHP. I dont work with anybody, I use a framework so I dont create libraries for my apps (most of the time). I have read a lot about Version Control and its benefits, but I dont understand how it would benefit somebody like me. The biggest benefit I can see it having is that if I posted the code on a remote server I could work from anywhere on any computer, but I carry my laptop like I carry my phone so again I dont see much of a reason there. Can somebody please explain to me in a simple manner the reasons for going with a VCS, and give me some good free ones I should try? Are there any hidden benefits/scenarios that you can think of that may sway me in any direction one way or the other. Thanks

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• Can an URL shortener pass parameters?

  - by ManniAT

  Hi, I use bit.ly to shorten my urls. My problem - paramters are not passed. Let me explain I use http://bit.ly/MYiPhoneApps which redirects (let's say) to http://iphone.pp-p.net/default.aspx Now when I try http://bit.ly/MYiPhoneApps?param=xx this param is not added to the resulting url. I know I could create an extra "short url" including a paramter - so http://bit.ly/WithParam would result in http://www.mysite.com/somepath/apage.aspx?Par1=yy and so forth. But what I want is to have a short URL directing to a page - and then I want to add a parameter to this shortened url - which shoul (of course) land at my page. Is this a shortcome of bit.ly (and others are maybe able to do it) - or does "parameter forwarding" not work with 301 redirections? Manfred

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• plot multi graphs with 2 y axis in 1 graph

  - by lytheone

  Hello, Currently I have a a text file with data at the first row is formatted as follow: time;wave height 1;wave height 2;....... I have column until wave height 19 and rows total 4000 rows. Data in the first column is time in second. From 2nd column onwards, it is wave height elevation which is in meter. I would like to plot the follow: ![alt text][1] on the x axis is time. the left hand side is wave height in m and on the right hand side is the distance between each measurment in a model. inside the graph there are 4 plots, each plot is repersent waveight 1, wave height 2etc at a defined distance related to the right hand side y asix. How would you code this in matlab? I am a begineer, please if you could, it will be very useful to give a bit more explain in your answer! Thank you!!!!!!!!!!

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• c++ macros question

  - by rabidmachine9

  can somebody explain the following code please? #if 1 // loop type #define FOR_IS_FASTER 1 #define WHILE_IS_FASTER 0 // indexing type #define PREINCREMENT_IS_FASTER 1 #define POSTINCREMENT_IS_FASTER 0 #else // loop type #define FOR_IS_FASTER 1 #define WHILE_IS_FASTER 0 // indexing type #define PREINCREMENT_IS_FASTER 0 #define POSTINCREMENT_IS_FASTER 1 #endif #if PREINCREMENT_IS_FASTER #define ZXP(z) (*++(z)) #define ZX(z) (*(z)) #define PZ(z) (++(z)) #define ZP(z) (z) #define ZOFF (1) #elif POSTINCREMENT_IS_FASTER #define ZXP(z) (*(z)++) #define ZX(z) (*(z)) #define PZ(z) (z) #define ZP(z) ((z)++) #define ZOFF (0) #endif I can understand what the functions are doing but for example how does the pre-processor choose which ZXP will be execute if we call it later? What the 1 and 0 stand for? thanks in advance

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• How do I create a view with a picker on the bottom and a table view on the top?

  - by Andy

  Hi - first time asker, long-time lurker. I am trying to create an iPhone view that has a date/time picker on the bottom half of the screen, and a grouped, single-section, four-row table view on the top half of the screen (almost identical to the one Apple shows in Fig. 2-4 of their View Controller Programming Guide (but then never goes on to explain). Conceptually, I think I understand that what I need is a main view with a pair of subviews - one for the picker, and one for the table view. I'm pretty sure I can make the picker function once I have it on-screen, and I'm pretty sure I can make the table view function too. What I can't for the life of me figure out is how, programmatically speaking, to get the two views onto the screen simultaneously. I can lay it out perfectly in Interface Builder, but then it all goes to hell when I switch to Xcode...the view appears with the picker, but no table view. Thanks, in advance, for any help you can offer.

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• Rails: unexpected behavior updating a shared instance

  - by Pascal Lindelauf

  I have a User object, that is related to a Post object via two different association paths: Post --(has_many)-- comments --(belongs to)-- writer (of type User) Post --(belongs to)-- writer (of type User) Say the following hold: user1.name == "Bill" post1.comments[1].writer == user1 post1.writer == user1 Now when I retrieve the post1 and its comments from the database and I update post1.comments[1].writer like so: post1.comments[1].writer.name = "John" I would expect post1.writer to equal "John" too. But it doesn't! It still equals "Bill". So there seems to be some caching going on, but the kind I would not expect. I would expect Rails to be clever enough to load exactly one instance of the user with name "Bill"; instead is appears to load two individual ones: one for each association path. Can someone explain how this works exactly and how I am to handle these types of situations the "Rails way"?

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• Should I stick only to AWS RDS Automated Backup or DB Snapshots?

  - by James Wise

  I am using AWS RDS for MySQL. With it comes on backup, I understand that amazon provides two types of backup - automated backup and database (DB) snapshot. The difference is explain in here - http://aws.amazon.com/rds/faqs/#23. However, I am still confuse if should I stick to automated backup only or both automated and manual (db snapshots). What do you think guys? What's the setup of your own? I heard to others that automated backup is not reliable due to some unrecoverable database when the DB instance is crashed so the DB snapshots are the way to rescue you. If I will do daily DB snapshots as similar settings to automated backup, I have gonna pay much bunch of bucks. Hope anyone could enlighten me or advise me the right set up. Thanks. James

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• Cannot initialize non-const reference from convertible type

  - by Julien L.

  Hi, I cannot initialize a non-const reference to type T1 from a convertible type T2. However, I can with a const reference. long l; const long long &const_ref = l; // fine long long &ref = l; // error: invalid initialization of reference of // type 'long long int&' from expression of type // 'long int' Most problems I encountered were related to r-values that cannot be assigned to a non-const reference. This is not the case here -- can someone explain? Thanks.

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• What benefits can Java developer have moving to a *NIX platform?

  - by dave-keiture

  Hi everyone, A friend of mine is a Java developer, who's using *NIX for ages. He claims that *NIX is for real Java geeks, whereas WIN is for dummies (and I'm one of them, according to him) and girls. When I ask him to argue his position, and explain, what's so good for Java developer on *NIX, he starts talking about console, wget, curl and grep. But sorry, wget and curl analogues exist for the WIN platform as well. As for the console - I'm using FAR Commander, and have access to the command line when I need. Moreover, even if I decide moving to *NIX, I will certainly use Netbeans or Eclipse there, so there will be no big difference. Guys, who use Java on *NIX, could you please give me a real killer examples, when *NIX (any util or technique) dramatically increases Java development productivity (in the way the hints are given in "The Pragmatic Programmer"), or, which is also important, gives more fun from the process. Thanks in advance!

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• Jquery draggable with zoom problem

  - by Manuel

  I am working on a page in witch all its contents are scaled by using zoom. The problem is that when I drag something in the page the dragging item gets a bad position that seems relative to the zoom amount. To solve this I tried to do some math on the position of the draggable component, but seems that even tho visually its corrected, the "true" position its not recalculated. here is some code to explain better: var zoom = Math.round((parseFloat($("body").css("zoom")) / 100)*10)/10; var x = $(this).data('draggable').position; $(this).data('draggable').position.left = Math.round(x.left/zoom); $(this).data('draggable').position.top = Math.round(x.top/zoom); Any help would be greatly appreciated

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• Kernel thread exit in linux

  - by Raffo

  Hi guys, I'm here to ask you the difference between a process and a thread in linux. I know that a thread for linux is just a "task", which shares with the father process things that they need to have in common (the address space and other important informations). I also know that the two are creating calling the same function ('clone()'), but there's still something that I'm missing: what really happens when a thread exit? What function is called inside the linux kernel? I know that when a process exits calls the do_exit function, but here or somewhere else there should be a way to understand if it is just a thread exiting or a whole process. Can you explain me this thing or redirect to some textbook?? I tried 'Understanding the linux kernel' but I was not satisfied with it. I'm asking this thing because a need to add things to the task_struct struct, but I need to discriminate how to manage those informations for a process and its children. Thank you.

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