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  • Multiple Inheritence with same Base Classes in Python

    - by Jordan Reiter
    I'm trying to wrap my head around multiple inheritance in python. Suppose I have the following base class: class Structure(object): def build(self, *args): print "I am building a structure!" self.components = args And let's say I have two classes that inherit from it: class House(Structure): def build(self, *args): print "I am building a house!" super(House, self).build(*args) class School(Structure): def build(self, type="Elementary", *args): print "I am building a school!" super(School, self).build(*args) Finally, a create a class that uses multiple inheritance: class SchoolHouse(School, House): def build(self, *args): print "I am building a schoolhouse!" super(School, self).build(*args) Then, I create a SchoolHouse object and run build on it: >>> sh = SchoolHouse() >>> sh.build("roof", "walls") I am building a schoolhouse! I am building a house! I am building a structure! So I'm wondering -- what happened to the School class? Is there any way to get Python to run both somehow? I'm wondering specifically because there are a fair number of Django packages out there that provide custom Managers for models. But there doesn't appear to be a way to combine them without writing one or the other of the Managers as inheriting from the other one. It'd be nice to just import both and use both somehow, but looks like it can't be done? Also I guess it'd just help to be pointed to a good primer on multiple inheritance in Python. I have done some work with Mixins before and really enjoy using them. I guess I just wonder if there is any elegant way to combine functionality from two different classes when they inherit from the same base class.

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  • Loading .dll/.exe from file into temporary AppDomain throws Exception

    Hi Gang, I am trying to make a Visual Studio AddIn that removes unused references from the projects in the current solution (I know this can be done, Resharper does it, but my client doesn't want to pay for 300 licences). Anyhoo, I use DTE to loop through the projects, compile their assemblies, then reflect over those assemblies to get their referenced assemblies and cross-examine the .csproj file. Problem: since the .dll/.exe I loaded up with Reflection doesn't unload until the app domian unloads, it is now locked and the projects can't be built again because VS tries to re-create the files (all standard stuff). I have tried creating temporary files, then reflecting over them...no worky, still have locked original files (I totally don’t understand that BTW). Now I am now going down the path of creating a temporary AppDomain to load the files into and then destroy. I am having problems loading the files though: The way I understand AddDomain.Load is that I should create and send a byte array of the assembly to it. I do that: FileStream fs = new FileStream(assemblyFile, FileMode.Open); byte[] assemblyFileBuffer = new byte[(int)fs.Length]; fs.Read(assemblyFileBuffer, 0, assemblyFileBuffer.Length); fs.Close(); AppDomainSetup domainSetup = new AppDomainSetup(); domainSetup.ApplicationBase = assemblyFileInfo.Directory.FullName; AppDomain tempAppDomain = AppDomain.CreateDomain("TempAppDomain", null, domainSetup); Assembly projectAssembly = tempAppDomain.Load(assemblyFileBuffer); The last line throws an exception: "Could not load file or assembly 'WindowsFormsApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.":"WindowsFormsApplication3, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"}" Any help or thoughts would be greatly appreciated. My head is lopsided from beating it against the wall... Thanks, Dan

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  • How to detect a gamepad button press on OSX 10.5 and higher?

    - by Steph Thirion
    How do I detect a button press on a USB gamepad on OSX 10.5 and higher? I can't wrap my head around the ridiculously complex HID Manager (even though apparently it was simplified with 10.5), and the code samples at Apple have thousands of lines of code that would take days to understand and isolate what I need, so I'd appreciate if someone posts a simple, and fully coded solution for this isolated problem. EDIT: so far all answers are links to source code or semi obscure libraries for all kinds of HID devices, which will require more research time than what I'd like to invest on this. I am starting a bounty to get an actual snippet of code that solves this simple problem (using an external library or not). EDIT POS BOUNTY: thanks to all for you help; but unfortunately the answer that has been automatically selected by the system is not working for me, can't figure out why; and the author has not yet replied to my comments. Any insight would be appreciated, but until a fix is found, anyone looking for resources on this topic should take this answer with a pinch of salt.

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  • HTML/jQuery/CSS Drop Down Menu Issue / Safari

    - by mmundiff
    I have a drop down menu that is coded in HTML, CSS, and jQuery and it works fine in Firefox and IE but not in Safari, and also not in Firefox on Mac. The drop down displays inline as opposed to list-item for the drop down in Safari. Any ideas why? <html> <head> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script> <script type="text/javascript" > $(document).ready(function(){ $('#menu li').hover( function() { //$('ul', this).css('display', 'block'); $('ul', this).fadeIn(200); var src = $('img.item', this).attr('src').match(/[^\.]+/) + '_over.png'; $('img.item', this).attr('src', src); }, function() { //$('ul', this).css('display', 'none'); $('ul', this).fadeOut(350); var src = $('img.item', this).attr('src').replace('_over', ''); $('img.item', this).attr('src', src); }); }); </script> <style type="text/css"> /* General */ body { arial, sans-serif; background-color: white; } * { padding: 0; margin: 0; } #menu{ white-space:nowrap; list-style:none; margin-left: 1px; } #menu ul { list-style: none; position:absolute; left:0; display:none; margin:0 -3px 0 -1px; padding:0; background: #000000; z-index: 500; margin-top: -4px; } #menu li{ display:inline; float: left; /* Added */ position:relative; } #menu li a { display: block; } #menu ul li { width:116px; float:left; border-top:1px dotted #666666; display: block; } #menu li ul { display: none; border-top: 1px black solid; text-align: left; } #menu ul a:hover { text-decoration:none; background: #efda83; color: #000000; } #menu ul a { text-decoration:none; display:block; height:15px; padding: 8px 5px; color:#efda83; font-size: 12px; } img{ border: 0 none; } .clear{ clear: both; } </style> </head> <body> <div> <ul id="menu"> <li ><a href="index.php"><img src="images/ssr_nav_home.png" class="item" alt="Home" /></a> </li> <li ><a href="about.php"><img src="images/ssr_nav_about.png" class="item" alt="About" /></a> <ul> <li><a href="about_contributors.php">Contributors</a></li> <li><a href="about_behind.php">Behind the Exhibit</a></li> <li><a href="about_sponsors.php">Sponsors</a></li> </ul> <div class="clear"></div> </li> <li ><a href="exhibit_intro.php"><img class="item" src="images/ssr_nav_exhibit.png" alt="Exhibit" /></a> <ul> <li><a href="exhibit_intro.php">Intro</a></li> <li><a href="exhibit_silkroad.php">Silk Road</a></li> <li><a href="exhibit_western_regions.php">Western Regions</a></li> <li><a href="exhibit_daily_life.php">Daily Life</a></li> <li><a href="exhibit_burial_practices.php">Burial Practices</a></li> <li><a href="exhibit_relevance.php">Relevance</a></li> </ul> <div class="clear"></div> </li> <li ><a href="visit.php"><img class="item" src="images/ssr_nav_visit.png" alt="Visit" /></a> <ul> <li><a href="visit_tickets.php">Tickets</a></li> <li><a href="visit_specials.php">Special Offers</a></li> <li><a href="visit_tours.php">Tours</a></li> <li><a href="visit_groups.php">Groups</a></li> </ul> <div class="clear"></div> </li> <li ><a href="events.php"><img class="item" src="images/ssr_nav_events.png" alt="Events" /></a> <ul> <li><a href="events_lectures.php">Lecture Series</a></li> <li><a href="events_symposium.php">Symposium</a></li> <li><a href="kids_and_family.php">Kids &amp; Family</a></li> <li><a href="events_calendar.php">Event Calendar</a></li> </ul> <div class="clear"></div> </li> <li ><a href="gallery.php"><img class="item" src="images/ssr_nav_images.png" alt="Gallery" /></a></li> <li ><a href="resources.php"><img class="item" src="images/ssr_nav_resources.png" alt="Resources" /></a> <ul> <li><a href="resources_teachers.php">For Teachers</a></li> <li><a href="kids_and_family.php">Kids &amp; Family</a></li> <li><a href="http://www.penn.museum/podcasts-and-videos/819-secrets-of-the-silk-road.html" rel="external">Podcasts &amp; Videos</a></li> <!-- <li><a href="map.php">Silk Road Map</a></li> <li><a href="resources_timeline.php">Timeline</a></li> --> <li><a href="resources_quiz.php">Quiz</a></li> <li><a href="glossary.php">Glossary</a></li> <li><a href="blogs.php">Blog</a></li> </ul> <div class="clear"></div> </li> <li ><a href="press.php"><img class="item" src="images/ssr_nav_press.png" alt="Press" /></a> <ul> <li><a href="press_release.php">Press Release</a></li> <li><a href="press_images.php">Press Images</a></li> <li><a href="press_bloggers.php">Bloggers</a></li> </ul> <div class="clear"></div> </li> </ul> </div> </body> </html>

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  • Multiple generic parameters on a html helper extension method

    - by WestDiscGolf
    What I'm trying to do is create an extension method for the HtmlHelper to create a specific output and associated details like TextBoxFor<. What I want to do is specify the property from the model class as per TextBoxFor<, then an associated controller action and other parameters. So far the signature of the method looks like: public static MvcHtmlString Create<TModel, TProperty, TController>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Expression<Action<TController>> action, object htmlAttributes) where TController : Controller where TModel : class The issue occurs when I go to call it. In my view if I call it as per the TextBoxFor without specifying the Model type I am able to specify the lambda expression to set the property which it's for, but when I go to specify the action I am unable to. However, when I specify the controller type Html.Create<HomeController>( ... ) I am unable to specify the model property that the control is to be created for. I want to be able to call it like <%= Html.Create(x => x.Title, controller => controller.action, null) %> I've been hitting my head for a few hours now on this issue over the past day, can anyone point me in the right direction?

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  • XAML get new width and height for Canvas

    - by Jack Navarro
    I have searched through many times but have not seen this before. Probably really simple question but can't wrap my head around it. Wrote a VSTO add-in for Excel that draws a Grid dynamically. Then launches a new window and replaces the contents of the Canvas with the generated Grid. The problem is with printing. When I call the print procedure the canvas.height and canvas.width returned is the old value prior to replacing it with the grid. Sample: string="<Grid Name=\"CanvasGrid\" xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">..Lots of stuff..</Grid>"; // Launch new window and replace the Canvas element WpfUserControl newWindow = new WpfUserControl(); newWindow.Show(); //To test MessageBox.Show(myCanvas.ActualWidth.ToString()); //return 894 Grid testGrid = myCanvas.FindName("CanvasGrid") as Grid; MessageBox.Show("Grid " + testGrid.ActualWidth.ToString()); //return 234 StringReader stringReader = new StringReader(LssAllcChrt); XmlReader xmlReader = XmlReader.Create(stringReader); Canvas myCanvas = newWindow.FindName("GrphCnvs") as Canvas; myCanvas.Children.Clear(); myCanvas.Children.Add((UIElement)XamlReader.Load(xmlReader)); //To test MessageBox.Show(myCanvas.ActualWidth.ToString()); //return 894 but should be much larger the Grid spans all three of my screens Grid testGrid = myCanvas.FindName("CanvasGrid") as Grid; MessageBox.Show("Grid " + testGrid.ActualWidth.ToString()); //return 234 but should be much larger the Grid spans all three of my screens //Run code from WpfUserControl.cs after it loads from button click Grid testGrid = canvas.FindName("CanvasGrid") as Grid; MessageBox.Show("Grid " + testGrid.ActualWidth.ToString()); //return 234 but should be much larger the Grid spans all three of my screens So basically I have no way of telling what my new width and height are.

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  • Rails - Why is HAML showing the full hash?

    - by Mr. Demetrius Michael
    View: !!! %html %head %title= full_title(yield(:title)) =stylesheet_link_tag "application", media: "all" =javascript_include_tag "application" =csrf_meta_tags =render 'layouts/shim' %body =render 'layouts/header' .container =flash.each do |key, value| %div{class: "alert alert-#{key}"} #{value} Controller def create @user = User.new(params[:user]) if @user.save flash[:success] = "This is Correct" redirect_to @user else flash[:wrong] = "no" render 'new' end end Regardless of the flash (:success or :wrong or otherwise) it always compiles the entire hash as html (below) Output: <!DOCTYPE html> .... <div class='container'> <div class='alert alert-wrong'>no</div> {:wrong=&gt;&quot;no&quot;} </div> </body> </html> I have no idea why {:wrong=&gt;&quot;no&quot;} is being displayed. I've been staring at this terminal for hours. What's interesting is that the hash is being outputted with the container id, but not in the alert class. It feels like an indentation problem, but I went through several permutations with no success.

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  • JS/CSS include section replacement, Debug vs Release

    - by Bayard Randel
    I'd be interested to hear how people handle conditional markup, specifically in their masterpages between release and debug builds. The particular scenario this is applicable to is handling concatenated js and css files. I'm currently using the .Net port of YUI compress to produce a single site.css and site.js from a large collection of separate files. One thought that occurred to me was to place the js and css include section in a user control or collection of panels and conditionally display the <link> and <script> markup based on the Debug or Release state of the assembly. Something along the lines of: #if DEBUG pnlDebugIncludes.visible = true #else pnlReleaseIncludes.visible = true #endif The panel is really not very nice semantically - wrapping <script> tags in a <div> is a bit gross; there must be a better approach. I would also think that a block level element like a <div> within <head> would be invalid html. Another idea was this could possibly be handled using web.config section replacements, but I'm not sure how I would go about doing that.

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  • Trouble with building up a string in Clojure

    - by Aki Iskandar
    Hi gang - [this may seem like my problem is with Compojure, but it isn't - it's with Clojure] I've been pulling my hair out on this seemingly simple issue - but am getting nowhere. I am playing with Compojure (a light web framework for Clojure) and I would just like to generate a web page showing showing my list of todos that are in a PostgreSQL database. The code snippets are below (left out the database connection, query, etc - but that part isn't needed because specific issue is that the resulting HTML shows nothing between the <body> and </body> tags). As a test, I tried hard-coding the string in the call to main-layout, like this: (html (main-layout "Aki's Todos" "Haircut<br>Study Clojure<br>Answer a question on Stackoverfolw")) - and it works fine. So the real issue is that I do not believe I know how to build up a string in Clojure. Not the idiomatic way, and not by calling out to Java's StringBuilder either - as I have attempted to do in the code below. A virtual beer, and a big upvote to whoever can solve it! Many thanks! ============================================================= ;The master template (a very simple POC for now, but can expand on it later) (defn main-layout "This is one of the html layouts for the pages assets - just like a master page" [title body] (html [:html [:head [:title title] (include-js "todos.js") (include-css "todos.css")] [:body body]])) (defn show-all-todos "This function will generate the todos HTML table and call the layout function" [] (let [rs (select-all-todos) sbHTML (new StringBuilder)] (for [rec rs] (.append sbHTML (str rec "<br><br>"))) (html (main-layout "Aki's Todos" (.toString sbHTML))))) ============================================================= Again, the result is a web page but with nothing between the body tags. If I replace the code in the for loop with println statements, and direct the code to the repl - forgetting about the web page stuff (ie. the call to main-layout), the resultset gets printed - BUT - the issue is with building up the string. Thanks again. ~Aki

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  • Help a CRUD programmer think about an "approval workflow"

    - by gerdemb
    I've been working on a web application that is basically a CRUD application (Create, Read, Update, Delete). Recently, I've started working on what I'm calling an "approval workflow". Basically, a request is generated for a material and then sent for approval to a manager. Depending on what is requested, different people need to approve the request or perhaps send it back to the requester for modification. The approvers need to keep track of what to approve what has been approved and the requesters need to see the status of their requests. As a "CRUD" developer, I'm having a hard-time wrapping my head around how to design this. What database tables should I have? How do I keep track of the state of the request? How should I notify users of actions that have happened to their requests? Is their a design pattern that could help me with this? Should I be drawing state-machines in my code? I think this is a generic programing question, but if it makes any difference I'm using Django with MySQL.

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  • LINQ to SQL: Reusable expression for property?

    - by coenvdwel
    Pardon me for being unable to phrase the title more exact. Basically, I have three LINQ objects linked to tables. One is Product, the other is Company and the last is a mapping table Mapping to store what Company sells which products and by which ID this Company refers to this Product. I am now retrieving a list of products as follows: var options = new DataLoadOptions(); options.LoadWith<Product>(p => p.Mappings); context.LoadOptions = options; var products = ( from p in context.Products select new { ProductID = p.ProductID, //BackendProductID = p.BackendProductID, BackendProductID = (p.Mappings.Count == 0) ? "None" : (p.Mappings.Count > 1) ? "Multiple" : p.Mappings.First().BackendProductID, Description = p.Description } ).ToList(); This does a single query retrieving the information I want. But I want to be able to move the logic behind the BackendProductID into the LINQ object so I can use the commented line instead of the annoyingly nested ternary operator statements for neatness and re-usability. So I added the following property to the Product object: public string BackendProductID { get { if (Mappings.Count == 0) return "None"; if (Mappings.Count > 1) return "Multiple"; return Mappings.First().BackendProductID; } } The list is still the same, but it now does a query for every single Product to get it's BackendProductID. The code is neater and re-usable, but the performance now is terrible. What I need is some kind of Expression or Delegate but I couldn't get my head around writing one. It always ended up querying for every single product, still. Any help would be appreciated!

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  • How to easily map c++ enums to strings

    - by Roddy
    I have a bunch of enum types in some library header files that I'm using, and I want to have a way of converting enum values to user strings - and vice-versa. RTTI won't do it for me, because the 'user strings' need to be a bit more readable than the enumerations. A brute force solution would be a bunch of functions like this, but I feel that's a bit too C-like. enum MyEnum {VAL1, VAL2,VAL3}; String getStringFromEnum(MyEnum e) { switch e { case VAL1: return "Value 1"; case VAL2: return "Value 2"; case VAL1: return "Value 3"; default: throw Exception("Bad MyEnum"); } } I have a gut feeling that there's an elegant solution using templates, but I can't quite get my head round it yet. UPDATE: Thanks for suggestions - I should have made clear that the enums are defined in a third-party library header, so I don't want to have to change the definition of them. My gut feeling now is to avoid templates and do something like this: char * MyGetValue(int v, char *tmp); // implementation is trivial #define ENUM_MAP(type, strings) char * getStringValue(const type &T) \ { \ return MyGetValue((int)T, strings); \ } ; enum eee {AA,BB,CC}; - exists in library header file ; enum fff {DD,GG,HH}; ENUM_MAP(eee,"AA|BB|CC") ENUM_MAP(fff,"DD|GG|HH") // To use... eee e; fff f; std::cout<< getStringValue(e); std::cout<< getStringValue(f);

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  • No idea how to solve SICP exercise 1.11

    - by Javier Badia
    This is not homework. Exercise 1.11: A function f is defined by the rule that f(n) = n if n<3 and f(n) = f(n - 1) + 2f(n - 2) + 3f(n - 3) if n 3. Write a procedure that computes f by means of a recursive process. Write a procedure that computes f by means of an iterative process. Implementing it recursively is simple enough. But I couldn't figure out how to do it iteratively. I tried comparing with the Fibonacci example given, but I didn't know how to use it as an analogy. So I gave up (shame on me) and Googled for an explanation, and I found this: (define (f n) (if (< n 3) n (f-iter 2 1 0 n))) (define (f-iter a b c count) (if (< count 3) a (f-iter (+ a (* 2 b) (* 3 c)) a b (- count 1)))) After reading it, I understand the code and how it works. But what I don't understand is the process needed to get from the recursive defintion of the function to this. I don't get how the code formed in someone's head. Could you explain the thought process needed to arrive at the solution?

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  • Find tag that contains certain text and add a class

    - by David Gard
    I have the following HTML, and I need to add a class to both <li> and <a> where the text 'Charts' exists (so not the second line, but rather the 4th and 5th). I cannot change the output of the HTML. <div class="wp-submenu-wrap"> <div class="wp-submenu-head">Charts</div> <ul> <li class="wp-first-item"> <a class="wp-first-item" tabindex="1" href="admin.php?page=charts">Charts</a> </li> <li> <a tabindex="1" href="admin.php?page=add-chart">Add Chart</a> </li> </ul> </div> I've tried doing this by locating the <a> tag that contains the text, but it is not working. Can somebody please point me in the correct direction? Thanks. Code that I've tried - $(document).ready(function(){ if(pagenow === 'admin_page_edit-chart') { var page = $('.wp-submenu-wrap a:contains["Charts"]'); page.addClass('current'); page.parent('li').addClass('current'); } });

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  • Simulating a contains If-Else using RewriteCond

    - by hlissner
    Hi! I'm trying to get my head around RewriteCond, and want to rewrite any requests either to a static html page (if it exists), or to a specific index.php (so long as the requested file doesn't exist). To illustrate the logic: if HTTP_HOST is '(www\.)?mydomain.com' if file exists: "/default/static/{REQUEST_URI}.html", then rewrite .* to /default/static/{REQUEST_URI}.html else if file exists: {REQUEST_FILENAME}, then do not rewrite else rewrite .* to /default/index.php I don't seem to have much trouble doing it when I don't need to test for the HTTP_HOST. Ultimately, this one .htaccess file will be handling requests for several domains. I know I could get around this with vhosts, but I'd like to figure out how to do it this way. Here's where I am at now: RewriteCond %{HTTP_HOST} ^(www\.)?mydomain\.com$ [NC] RewriteCond /default/static/%{REQUEST_URI}.html -f RewriteRule . /default/static/%{REQUEST_URI}.html [L,NC] RewriteCond %{REQUEST_FILENAME} !-f RewriteRule . /default/index.php [L,QSA] I'm not too familiar with some of the other flags, will any of them be of use here (like chain|C, next|N or skip|S)? Thanks in advance!

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  • How would you code an efficient Circular Buffer in Java or C#

    - by Cheeso
    I want a simple class that implements a fixed-size circular buffer. It should be efficient, easy on the eyes, generically typed. EDIT: It need not be MT-capable, for now. I can always add a lock later, it won't be high-concurrency in any case. Methods should be: .Add and I guess .List, where I retrieve all the entries. On second thought, Retrieval I think should be done via an indexer. At any moment I will want to be able to retrieve any element in the buffer by index. But keep in mind that from one moment to the next Element[n] may be different, as the Circular buffer fills up and rolls over. This isn't a stack, it's a circular buffer. Regarding "overflow": I would expect internally there would be an array holding the items, and over time the head and tail of the buffer will rotate around that fixed array. But that should be invisible from the user. There should be no externally-detectable "overflow" event or behavior. This is not a school assignment - it is most commonly going to be used for a MRU cache or a fixed-size transaction or event log.

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  • Can't get jQuery to wokr with Prototype - tried everything....

    - by thinkfuture
    Ok so here is the situation. Been pulling my hair out on this one. I'm a noob at this. Only been using rails for about 6 weeks. I'm using the standard setup package, and my code leverages prototype helpers heavily. Like I said, noob ;) So I'm trying to put in some jQuery effects, like PrettyPhoto. But what happens is that when the page is first loaded, PrettyPhoto works great. However, once someone uses a Prototype helper, like a link created with link_to_remote, Prettyphoto stops working. I've tried jRails, all of the fixes proposed on the JQuery site to stop conflicts... http://docs.jquery.com/Using_jQuery_with_Other_Libraries ...even done some crazy things likes renaming all of the $ in prototype.js to $$$ to no avail. Either the prototype helpers break, or jQuery breaks. Seems nothing I do can get these to work together. Any ideas? Here is part of my application.html.erb <%= javascript_include_tag 'application' %> <%= javascript_include_tag 'tooltip' %> <%= javascript_include_tag 'jquery' %> <%= javascript_include_tag 'jquery-ui' %> <%= javascript_include_tag "jquery.prettyPhoto" %> <%= javascript_include_tag 'prototype' %> <%= javascript_include_tag 'scriptalicious' %> </head> <body> <script type="text/javascript" charset="utf-8"> jQuery(document).ready( function() { jQuery("a[rel^='prettyPhoto']").prettyPhoto(); }); </script> If I put prototype before jquery, the prototype helpers don't work If I put the noconflict clause in, neither works. Thanks in advance! Chris

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  • Is sending a hashed password over the wire a security hole?

    - by Ubiquitous Che
    I've come across a system that is in use by a company that we are considering partnering with on a medium-sized (for us, not them) project. They have a web service that we will need to integrate with. My current understanding of proper username/password management is that the username may be stored as plaintext in the database. Every user should have a unique pseudo-random salt, which may also be stored in plaintext. The text of their password must be concatenated with the salt and then this combined string may be hashed and stored in the database in an nvarchar field. So long as passwords are submitted to the website (or web service) over plaintext, everything should be just lovely. Feel free to rip into my understanding as summarized above if I'm wrong. Anyway, back to the subject at hand. The WebService run by this potential partner doesn't accept username and password, which I had anticipated. Instead, it accepts two string fields named 'Username' and 'PasswordHash'. The 'PasswordHash' value that I have been given does indeed look like a hash, and not just a value for a mis-named password field. This is raising a red flag for me. I'm not sure why, but I feel uncomfortable sending a hashed password over the wire for some reason. Off the top of my head I can't think of a reason why this would be a bad thing... Technically, the hash is available on the database anyway. But it's making me nervous, and I'm not sure if there's a reason for this or if I'm just being paranoid.

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  • Summarising grouped records in a dataframe in R (...again)

    - by monch1962
    Hello all, (I tried to ask this question earlier today, but later realised I over-simplified the question; the answers I received were correct, but I couldn't use them because of my over-simplification of the problem in the original question. Here's my 2nd attempt...) I have a data frame in R that looks like: "Timestamp", "Source", "Target", "Length", "Content" 0.1 , P1 , P2 , 5 , "ABCDE" 0.2 , P1 , P2 , 3 , "HIJ" 0.4 , P1 , P2 , 4 , "PQRS" 0.5 , P2 , P1 , 2 , "ZY" 0.9 , P2 , P1 , 4 , "SRQP" 1.1 , P1 , P2 , 1 , "B" 1.6 , P1 , P2 , 3 , "DEF" 2.0 , P2 , P1 , 3 , "IJK" ... and I want to convert this to: "StartTime", "EndTime", "Duration", "Source", "Target", "Length", "Content" 0.1 , 0.4 , 0.3 , P1 , P2 , 12 , "ABCDEHIJPQRS" 0.5 , 0.9 , 0.4 , P2 , P1 , 6 , "ZYSRQP" 1.1 , 1.6 , 0.5 , P1 , P2 , 4 , "BDEF" ... Trying to put this into English, I want to group consecutive records with the same 'Source' and 'Target' together, then print out a single record per group showing the StartTime, EndTime & Duration (=EndTime-StartTime) for that group, along with the sum of the Lengths for that group, and a concatenation of the Content (which will all be strings) in that group. The TimeOffset values will always increase throughout the data frame. I had a look at melt/recast and have a feeling that it could be used to solve the problem, but couldn't get my head around the documentation. I suspect it's possible to do this within R, but I really don't know where to start. In a pinch I could export the data frame out and do it in e.g. Python, but I'd prefer to stay within R if possible. Thanks in advance for any assistance you can provide

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  • Behavior of <- NULL on lists versus data.frames for removing data

    - by Ananda Mahto
    Many R users eventually figure out lots of ways to remove elements from their data. One way is to use NULL, particularly when you want to do something like drop a column from a data.frame or drop an element from a list. Eventually, a user comes across a situation where they want to drop several columns from a data.frame at once, and they hit upon <- list(NULL) as the solution (since using <- NULL will result in an error). A data.frame is a special type of list, so it wouldn't be too tough to imagine that the approaches for removing items from a list should be the same as removing columns from a data.frame. However, they produce different results, as can be seen in the example below. ## Make some small data--two data.frames and two lists cars1 <- cars2 <- head(mtcars)[1:4] cars3 <- cars4 <- as.list(cars2) ## Demonstration that the `list(NULL)` approach works cars1[c("mpg", "cyl")] <- list(NULL) cars1 # disp hp # Mazda RX4 160 110 # Mazda RX4 Wag 160 110 # Datsun 710 108 93 # Hornet 4 Drive 258 110 # Hornet Sportabout 360 175 # Valiant 225 105 ## Demonstration that simply using `NULL` does not work cars2[c("mpg", "cyl")] <- NULL # Error in `[<-.data.frame`(`*tmp*`, c("mpg", "cyl"), value = NULL) : # replacement has 0 items, need 12 Switch to applying the same concept to a list, and compare the difference in behavior. ## Does not fully drop the items, but sets them to `NULL` cars3[c("mpg", "cyl")] <- list(NULL) # $mpg # NULL # # $cyl # NULL # # $disp # [1] 160 160 108 258 360 225 # # $hp # [1] 110 110 93 110 175 105 ## *Does* drop the `list` items while this would ## have produced an error with a `data.frame` cars4[c("mpg", "cyl")] <- NULL # $disp # [1] 160 160 108 258 360 225 # # $hp # [1] 110 110 93 110 175 105 The main questions I have are, if a data.frame is a list, why does it behave so differently in this scenario? Is there a foolproof way of knowing when an element will be dropped, when it will produce an error, and when it will simply be given a NULL value? Or do we depend on trial-and-error for this?

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  • Haskell Cons Operator (:)

    - by Carson Myers
    I am really new to Haskell (Actually I saw "Real World Haskell" from O'Reilly and thought "hmm, I think I'll learn functional programming" yesterday) and I am wondering: I can use the construct operator to add an item to the beginning of a list: 1 : [2,3] [1,2,3] I tried making an example data type I found in the book and then playing with it: --in a file data BillingInfo = CreditCard Int String String | CashOnDelivery | Invoice Int deriving (Show) --in ghci $ let order_list = [Invoice 2345] $ order_list [Invoice 2345] $ let order_list = CashOnDelivery : order_list $ order_list [CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, CashOnDelivery, ...- etc... it just repeats forever, is this because it uses lazy evaluation? -- EDIT -- okay, so it is being pounded into my head that let order_list = CashOnDelivery:order_list doesn't add CashOnDelivery to the original order_list and then set the result to order_list, but instead is recursive and creates an infinite list, forever adding CashOnDelivery to the beginning of itself. Of course now I remember that Haskell is a functional language and I can't change the value of the original order_list, so what should I do for a simple "tack this on to the end (or beginning, whatever) of this list?" Make a function which takes a list and BillingInfo as arguments, and then return a list? -- EDIT 2 -- well, based on all the answers I'm getting and the lack of being able to pass an object by reference and mutate variables (such as I'm used to)... I think that I have just asked this question prematurely and that I really need to delve further into the functional paradigm before I can expect to really understand the answers to my questions... I guess what i was looking for was how to write a function or something, taking a list and an item, and returning a list under the same name so the function could be called more than once, without changing the name every time (as if it was actually a program which would add actual orders to an order list, and the user wouldn't have to think of a new name for the list each time, but rather append an item to the same list).

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  • PyGTK: Trouble with size of ScrolledWindow

    - by canavanin
    Hi everyone! I am using PyGTK and the gtk.Assistant. On one page I have placed a treeview (one column, just strings) in a gtk.ScrolledWindow (I wanted the vertical scrollbar, since the list contains about 35 items). Everything is working fine; the only thing that bugs me is that I have not been able to figure out from the documentation how to set the size of the scrolled window. Currently only three items are displayed at a time; I would like to set this number to 10 or so. Below is the code. As you can see I have tried using a gtk.Adjustment to influence the scrolled window's size, but as - once more - I have been incompetent at retrieving the required info from the documentation, I don't actually know what values should be put into there. self.page7 = gtk.VBox() # The gtk.Adjustment: page_size = gtk.Adjustment(lower=10, page_size=100) # just used some arbitrary numbers here >_< scrolled_win = gtk.ScrolledWindow(page_size) scrolled_win.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC) # only display scroll bars when required self.character_traits_treeview = gtk.TreeView() self.character_traits_treestore = gtk.TreeStore(str) self.character_traits_treeview.set_model(self.character_traits_treestore) tc = gtk.TreeViewColumn("Character traits") self.character_traits_treeview.append_column(tc) cr = gtk.CellRendererText() tc.pack_start(cr, True) tc.add_attribute(cr, "text", 0) self.character_trait_selection = self.character_traits_treeview.get_selection() self.character_trait_selection.connect('changed', self.check_number_of_character_trait_selections) self.character_trait_selection.set_mode(gtk.SELECTION_MULTIPLE) self.make_character_traits_treestore() # adding the treeview to the scrolled window: scrolled_win.add(self.character_traits_treeview) self.page7.pack_start(scrolled_win, False, False, 0) self.assistant.append_page(self.page7) self.assistant.set_page_title(self.page7, "Step 7: Select 2-3 character traits") self.assistant.set_page_type(self.page7, gtk.ASSISTANT_PAGE_CONTENT) self.assistant.set_page_complete(self.page7, False) def check_number_of_character_trait_selections(self, blah): # ... def make_character_traits_treestore(self): # ... I know I should RTFM, but as I can't make head or tail of it, and as further searching, too, has been to no avail, I'm just hoping that someone on here can give me a hint. Thanks a lot in advance! PS: Here are the links to: the gtk.ScrolledWindow documentation the gtk.Adjustment documentation

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  • git changes modification time of files

    - by tanascius
    In the GitFaq I can read, that Git sets the current time as the timestamp on every file it modifies, but only those. However, I tried this command sequence (EDIT: added complete command sequence) $ git init test && cd test Initialized empty Git repository in d:/test/.git/ exxxxxxx@wxxxxxxx /d/test (master) $ touch filea fileb exxxxxxx@wxxxxxxx /d/test (master) $ git add . exxxxxxx@wxxxxxxx /d/test (master) $ git commit -m "first commit" [master (root-commit) fcaf171] first commit 0 files changed, 0 insertions(+), 0 deletions(-) create mode 100644 filea create mode 100644 fileb exxxxxxx@wxxxxxxx /d/test (master) $ ls -l > filea exxxxxxx@wxxxxxxx /d/test (master) $ touch fileb -t 200912301000 exxxxxxx@wxxxxxxx /d/test (master) $ ls -l total 1 -rw-r--r-- 1 exxxxxxx Administ 132 Feb 12 18:36 filea -rw-r--r-- 1 exxxxxxx Administ 0 Dec 30 10:00 fileb exxxxxxx@wxxxxxxx /d/test (master) $ git status -a warning: LF will be replaced by CRLF in filea # On branch master warning: LF will be replaced by CRLF in filea # Changes to be committed: # (use "git reset HEAD <file>..." to unstage) # # modified: filea # exxxxxxx@wxxxxxxx /d/test (master) $ git checkout . exxxxxxx@wxxxxxxx /d/test (master) $ ls -l total 0 -rw-r--r-- 1 exxxxxxx Administ 0 Feb 12 18:36 filea -rw-r--r-- 1 exxxxxxx Administ 0 Feb 12 18:36 fileb Now my question: Why did git change the timestamp of file fileb? I'd expect the timestamp to be unchanged. Are my commands causing a problem? Maybe it is possible to do something like a git checkout . --modified instead? I am using git version 1.6.5.1.1367.gcd48 under mingw32/windows xp.

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  • ADO.NET DataTable/DataRow Thread Safety

    - by Allen E. Scharfenberg
    Introduction A user reported to me this morning that he was having an issue with inconsistent results (namely, column values sometimes coming out null when they should not be) of some parallel execution code that we provide as part of an internal framework. This code has worked fine in the past and has not been tampered with lately, but it got me to thinking about the following snippet: Code Sample lock (ResultTable) { newRow = ResultTable.NewRow(); } newRow["Key"] = currentKey; foreach (KeyValuePair<string, object> output in outputs) { object resultValue = output.Value; newRow[output.Name] = resultValue != null ? resultValue : DBNull.Value; } lock (ResultTable) { ResultTable.Rows.Add(newRow); } (No guarantees that that compiles, hand-edited to mask proprietery information.) Explanation We have this cascading type of locking code other places in our system, and it works fine, but this is the first instance of cascading locking code that I have come across that interacts with ADO .NET. As we all know, members of framework objects are usually not thread safe (which is the case in this situation), but the cascading locking should ensure that we are not reading and writing to ResultTable.Rows concurrently. We are safe, right? Hypothesis Well, the cascading lock code does not ensure that we are not reading from or writing to ResultTable.Rows at the same time that we are assigning values to columns in the new row. What if ADO .NET uses some kind of buffer for assigning column values that is not thread safe--even when different object types are involved (DataTable vs. DataRow)? Has anyone run into anything like this before? I thought I would ask here at StackOverflow before beating my head against this for hours on end :) Conclusion Well, the consensus appears to be that changing the cascading lock to a full lock has resolved the issue. That is not the result that I expected, but the full lock version has not produced the issue after many, many, many tests. The lesson: be wary of cascading locks used on APIs that you do not control. Who knows what may be going on under the covers!

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  • Is there a more efficent way to randomise a set of linq results?

    - by Matthew De'Loughry
    Hi just wondering if you could help I've produced a function to get back a random set of submission depnding on the amount passed to it, but I worry that even though it works now with a small amount of data when the a large amount is passed through it would become efficent and cause problems. Just wondering if you could suggest a more efficent way of doing the following: public List<Submission> GetRandomWinners(int id) { List<Submission> submissions = new List<Submission>(); int amount = (DbContext().Competitions .Where(s => s.CompetitionId == id).FirstOrDefault()).NumberWinners; for(int i = 1 ; i <= amount; i++) { bool added = false; while (!added) { bool found = false; var randSubmissions = DbContext().Submissions .Where(s => s.CompetitionId == id && s.CorrectAnswer).ToList(); int count = randSubmissions.Count(); int index = new Random().Next(count); foreach (var sub in submissions ) { if (sub == randSubmissions.Skip(index).FirstOrDefault()) found = true; } if (!found) { submissions.Add(randSubmissions.Skip(index).FirstOrDefault()); added = true; } } } return submissions; } As I say I have this fully working and bringing back the wanted result just I'm not liking the foreach and while checks in there and my head has just turned to mush now try to come up with the above soloution. Thanks Matt

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