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  • Add string to another string

    - by daemonfire300
    Hi there, I currently encountered a problem: I want to handle adding strings to other strings very efficiently, so I looked up many methods and techniques, and I figured the "fastest" method. But I quite can not understand how it actually works: def method6(): return ''.join([`num` for num in xrange(loop_count)]) From source (Method 6) Especially the ([numfor num in xrange(loop_count)]) confused me totally.

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  • A question about making a C# class persistent during a file load

    - by Adam
    Apologies for the indescriptive title, however it's the best I could think of for the moment. Basically, I've written a singleton class that loads files into a database. These files are typically large, and take hours to process. What I am looking for is to make a method where I can have this class running, and be able to call methods from within it, even if it's calling class is shut down. The singleton class is simple. It starts a thread that loads the file into the database, while having methods to report on the current status. In a nutshell it's al little like this: public sealed class BulkFileLoader { static BulkFileLoader instance = null; int currentCount = 0; BulkFileLoader() public static BulkFileLoader Instance { // Instanciate the instance class if necessary, and return it } public void Go() { // kick of 'ProcessFile' thread } public void GetCurrentCount() { return currentCount; } private void ProcessFile() { while (more rows in the import file) { // insert the row into the database currentCount++; } } } The idea is that you can get an instance of BulkFileLoader to execute, which will process a file to load, while at any time you can get realtime updates on the number of rows its done so far using the GetCurrentCount() method. This works fine, except the calling class needs to stay open the whole time for the processing to continue. As soon as I stop the calling class, the BulkFileLoader instance is removed, and it stops processing the file. What I am after is a solution where it will continue to run independently, regardless of what happens to the calling class. I then tried another approach. I created a simple console application that kicks off the BulkFileLoader, and then wrapped it around as a process. This fixes one problem, since now when I kick off the process, the file will continue to load even if I close the class that called the process. However, now the problem I have is that cannot get updates on the current count, since if I try and get the instance of BulkFileLoader (which, as mentioned before is a singleton), it creates a new instance, rather than returning the instance that is currently in the executing process. It would appear that singletons don't extend into the scope of other processes running on the machine. In the end, I want to be able to kick off the BulkFileLoader, and at any time be able to find out how many rows it's processed. However, that is even if I close the application I used to start it. Can anyone see a solution to my problem?

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  • Encrypt/ Secure communication Android app <-> REST webservice

    - by Ascorbin
    I want to create a backend for my android app with Tapestry5 and this http://code.google.com/p/t5-restful-webservices/ plugin. The app will communicate with the server by calling REST methods both for registered users (that would be easy to secure I guess) as well as unregistered users. Now of course I don't want people to just call that webservice from a browser. How can I make sure that only my app can make calls to this backend?

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  • How do I get the current Cmdlet from another object?

    - by John Vottero
    What's the best way to get the current PowerShell Cmdlet from another object? If I create a helper object that is not a Cmdlet but will be called by Cmdlets, the helper methods may want to call WriteVerbose, WriteDebug etc. What's the best way to get access to that? Is there a static PowerShell method that will return the current Cmdlet or do I need to have the Cmdlet pass itself to the helper?

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  • Refactoring Singleton Overuse

    - by drharris
    Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

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  • quartz 2d multiple UIViews

    - by coure06
    I want to create two UIViews in quartz 2D application. First UIView for static text, it will redraw automatically after each one second. Second UIView for animated text, it will be redrawn automatically after each .1 second. How can i create multiple Views/Layers? Is there drawRect methods will be different?

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  • What common routines do you put in your Program.cs for C#

    - by Rick
    I'm interested in any common routine/procedures/methods that you might use in you Program.cs when creating a .NET project. For instance I commonly use the following code in my desktop applications to allow easy upgrades, single instance execution and friendly and simple reporting of uncaught system application errors. using System; using System.Diagnostics; using System.Threading; using System.Windows.Forms; namespace NameoftheAssembly { internal static class Program { /// <summary> /// The main entry point for the application. Modified to check for another running instance on the same computer and to catch and report any errors not explicitly checked for. /// </summary> [STAThread] private static void Main() { //for upgrading and installing newer versions string[] arguments = Environment.GetCommandLineArgs(); if (arguments.GetUpperBound(0) > 0) { foreach (string argument in arguments) { if (argument.Split('=')[0].ToLower().Equals("/u")) { string guid = argument.Split('=')[1]; string path = Environment.GetFolderPath(Environment.SpecialFolder.System); var si = new ProcessStartInfo(path + "\\msiexec.exe", "/x" + guid); Process.Start(si); Application.Exit(); } } //end of upgrade } else { bool onlyInstance = false; var mutex = new Mutex(true, Application.ProductName, out onlyInstance); if (!onlyInstance) { MessageBox.Show("Another copy of this running"); return; } AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException; Application.ThreadException += ApplicationThreadException; Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e) { try { var ex = (Exception) e.ExceptionObject; MessageBox.Show("Whoops! Please contact the developers with the following" + " information:\n\n" + ex.Message + ex.StackTrace, " Fatal Error", MessageBoxButtons.OK, MessageBoxIcon.Stop); } catch (Exception) { //do nothing - Another Exception! Wow not a good thing. } finally { Application.Exit(); } } public static void ApplicationThreadException(object sender, ThreadExceptionEventArgs e) { try { MessageBox.Show("Whoops! Please contact the developers with the following" + " information:\n\n" + e.Exception.Message + e.Exception.StackTrace, " Error", MessageBoxButtons.OK, MessageBoxIcon.Stop); } catch (Exception) { //do nothing - Another Exception! Wow not a good thing. } } } } I find these routines to be very helpful. What methods have you found helpful in Program.cs?

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  • Connecting C++ backend to Javascript

    - by baseballtank13
    I was hoping to make a website that displays a google map with points based of information returned by a C++ function. I know you can use Java Server Pages to call java methods on the server with javascript. Would there be a way to connect C++ code on the server with javascript in order to produce the same result as java server pages?

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  • Silverlight controls in aspx page

    - by Argons
    I'm developing a web site, and i'm using infragistics for web, but I want to use in some pages silverlight controls (Infragistics too). Is there a way to access a silverlight control's properties and methods from an aspx page? Thanks in advance for the help.

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  • jQuery each doesn't have a callback-possibility?

    - by Martti Laine
    Hello I have a loop created with each, check this example: $('.foo').each(function(i){ //do stuff }); Is there any possibility to run a functions when this loop has ended? Couldn't find it on docs or Google. I can make it work without this kind of solution, but it's always good to search for and use the simpliest methods. Martti Laine

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  • Generics List Interface...newb question

    - by newToProgramming
    The List interface is the following: public interface List<E>{ public boolean add(Object e); public boolean remove(Object e); public boolean contains(Object e); ...etc Why aren't the add, remove and contains methods written like the following? public boolean add(E e) public boolean remove(E e) public boolean contains(E e)

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  • Why are static classes considered “classes” and “reference types”?

    - by Timwi
    I’ve been pondering about the C# and CIL type system today and I’ve started to wonder why static classes are considered classes. There are many ways in which they are not really classes: A “normal” class can contain non-static members, a static class can’t. In this respect, a class is more similar to a struct than it is to a static class, and yet structs have a separate name. You can have a reference to an instance of a “normal” class, but not a static class (despite it being considered a “reference type”). In this respect, a class is more similar to an interface than it is to a static class, and yet interfaces have a separate name. The name of a static class can never be used in any place where a type name would normally fit: you can’t declare a variable of this type, you can’t use it as a base type, and you can’t use it as a generic type parameter. In this respect, static classes are somewhat more like namespaces. A “normal” class can implement interfaces. Once again, that makes classes more similar to structs than to static classes. A “normal” class can inherit from another class. It is also bizarre that static classes are considered to derive from System.Object. Although this allows them to “inherit” the static methods Equals and ReferenceEquals, the purpose of that inheritance is questionable as you would call those methods on object anyway. C# even allows you to specify that useless inheritance explicitly on static classes, but not on interfaces or structs, where the implicit derivation from object and System.ValueType, respectively, actually has a purpose. Regarding the subset-of-features argument: Static classes have a subset of the features of classes, but they also have a subset of the features of structs. All of the things that make a class distinct from the other kinds of type, do not seem to apply to static classes. Regarding the typeof argument: Making a static class into a new and different kind of type does not preclude it from being used in typeof. Given the sheer oddity of static classes, and the scarcity of similarities between them and “normal” classes, shouldn’t they have been made into a separate kind of type instead of a special kind of class?

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  • How to get path from a variable

    - by yoshco
    Following http://stackoverflow.com/questions/659647/how-to-get-folder-path-from-file-path-with-cmd I want to strip the path (without the filename) from a variable. following the logic of the methods discussed above I would like to use batch bellow, which doesn't work. any takers? possible? set cpp="C:\temp\lib.dll" echo %cpp% "C:\temp\lib.dll" echo %~dpcpp "C:\temp\" > doesn't work

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  • Problem when subClassing NSDate

    - by iFloh
    Hi, I first time tried to subClassed an NSDate to give it 2 methods that I need. Compiles fine, but in runtime I try to access it I get an error. Lets say I just want the current date which is unmodified in the subClass: [myNSDate date]; I get the error -[NSDate initWithTimeIntervalSinceReferenceDate:]: method only defined for abstract class. Define -[myNSDate initWithTimeIntervalSinceReferenceDate:]! what is different?

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  • OpenMP implementations in VC++ 2008, 2010

    - by John
    Depending on implementation, OMP can be quite useful to parallelize fairly arbitrary bits of code - e.g a parallel section inside a method that calls two independent methods - or it can be bad. It depends on how threads are created/cached, I think. How does the VC++ 2008 implementation work? And is the 2010 implementation significantly different in terms of features and performance/flexibility?

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  • What's static function for in c?

    - by user198729
    I only see static methods by which we don't need to instantiate a class to call the method. What's the purpose of a static function? static GtkWidget * create_bbox (gint horizontal, char *title, gint spacing, gint layout) { ... }

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  • how to parse self closing tag in xml file

    - by ajay-sharma2
    Hi, I am working on an iphone application in which I am consuming a webservice. So i am parsing the XML file data. any idea about how to parse self closing tag like: State/ and how to read data of self tag like: Contact Email="[email protected]" Name="PhD" Phone="123-521-3388" Source="location"/ I am parsing xml file using NSXMLPARSER class methods and library Thanks,

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  • Is it multitasking?

    - by Newbie
    Consider the below program myThread = new Thread( new ThreadStart( delegate { Method1(); Method2(); } ) ); Is it that 2 threads are getting called parallely(multitasking) or a single thread is calling the methods sequentially? It's urgent.

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  • Learn Prolog Now! DCG Practice Example

    - by Timothy
    I have been progressing through Learn Prolog Now! as self-study and am now learning about Definite Clause Grammars. I am having some difficulty with one of the Practical Session's tasks. The task reads: The formal language anb2mc2mdn consists of all strings of the following form: an unbroken block of as followed by an unbroken block of bs followed by an unbroken block of cs followed by an unbroken block of ds, such that the a and d blocks are exactly the same length, and the c and d blocks are also exactly the same length and furthermore consist of an even number of cs and ds respectively. For example, ε, abbccd, and aaabbbbccccddd all belong to anb2mc2mdn. Write a DCG that generates this language. I am able to write rules that generate andn, b2mc2m, and even anb2m and c2mndn... but I can't seem to join all these rules into anb2mc2mdn. The following are my rules that can generate andn and b2mc2m. s1 --> []. s1 --> a,s1,d. a --> [a]. d --> [d]. s2 --> []. s2 --> c,c,s2,d,d. c --> [c]. d --> [d]. Is anb2mc2mdn really a CFG, and is it possible to write a DCG using only what was taught in the lesson (no additional arguments or code, etc)? If so, can anyone offer me some guidance how I can join these so that I can solve the given task?

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