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  • How to sort an NSMutableArray of objects by a member of its class, that is an int or float

    - by J. Dave
    I have a class (from NSObject) that contains: NSString name int position float speed I then create an array (NSMutableArray) of objects from this class. I would like to then sort the array by the 'speed' value, which is a float. I initially has the float value as an NSNumber and the int as NSInteger, and I was successfully sorting with: [myMutableArray sortUsingFunction:compareSelector context:@selector(position)]; where myMutableArray is my array of objects. here is the function: static int compareSelector(id p1, id p2, void *context) { SEL methodSelector = (SEL)context; id value1 = [p1 performSelector:methodSelector]; id value2 = [p2 performSelector:methodSelector]; return [value1 compare:value2]; } Now that I am using int instead of NSInteger, the above code does not work. Is there a more low-level command that I should be using to execute the sort? Thank!

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  • How do I create an empty Django formset using modelformset_factory?

    - by nbolton
    I'm creating a formset, but it seems to populate it with all of the existing data in the table for that object. I can't figure out how to start with a blank formset; the only way seems to be to delete all of the data from the table, but clearly this isn't an option. I will post code if necessary (but there's lots of it, so knowing what is relevant is tricky).

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  • Is it inefficient to access a python class member container in a loop statement?

    - by Dave
    Hi there. I'm trying to adopt some best practices to keep my python code efficient. I've heard that accessing a member variable inside of a loop can incur a dictionary lookup for every iteration of the loop, so I cache these in local variables to use inside the loop. My question is about the loop statement itself... if I have the following class: class A(object): def init(self) self.myList = [ 'a','b','c', 'd', 'e' ] Does the following code in a member function incur one, or one-per-loop-iteration (5) dictionary lookups? for letter in self.myList: print letter IE, should I adopt the following pattern, if I am concerned about efficiency... localList = self.myList for letter in localList: print letter or is that actually LESS efficient due to the local variable assign? Note, I am aware that early optimization is a dangerous pitfall if I'm concerned about the overall efficiency of code development. Here I am specifically asking about the efficiency of the code, not the coding. Thanks in advance! D

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  • How to store NSMutableArray of user defined class objects to file system in iphone?

    - by chaitanya
    Can anyone please tell me how to write NSMutableArray of custom class objects to file? below is the code which i am using to write my array "medicationsArray" to file. medicationsArray contains the objects of below medicationData class @interface medicationData: NSObject { NSString *drName; NSString *date; NSString *description; } @end NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES); NSString *documentDir = [path objectAtIndex:0]; NSString *pathWithFileName; NSString *pathWithFileName = [NSString stringWithFormat:@"%@/medicationsArray",documentDir]; [medicationsArray writeToFile:pathWithFileName atomically:NO]; by using this code i am not able to create a file. can anyone help me in this, thanks in advance

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  • C++ Variable declarable in function body, but not class member?

    - by anon
    I want to create a C++ class with the following type: It can be declared inside of a function. It can be declared inside of a member function. It can not be declared as a class member. The use of this: think "Root" objects for a GC. Is this possible in C++? In particular, I'm using g++. Willing to switch to clang. Either templates or macro solution fine. Thanks!

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  • What could possibly cause this error(when declaring an object inside a class) ? //noobie question

    - by M4design
    I'm battling with this assignment :) I've got two classes: Ocean and Grid. When I declare an object of the Grid inside the Ocean: unsigned int sharkCount; Grid grid; The compiler/complainer says: error C2146: syntax error : missing ';' before identifier 'grid' Can you possibly predict what produces this error with the limited info' I provided? It seems that as if the Ocean doesn't like the Grid class. Could this be because of the poor implementation of the grid class. BTW the Grid has a default constructor. Yet the error happens in compiling time!. Thanks. EDIT: They're each in separate header file, and I've included the Grid.h in the Ocean.h.

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  • CSS Float left question

    - by Minghui Yu
    <div id="slideshow-prevnext" class="slideshow-prevnext"> <a id="prev" class="left" href="#"><span class="invisible">Prev</span></a> <a id="next" class="right" href="#"><span class="invisible">Next</span></a> <a href="#" class="dot">&nbsp;</a> <a href="#" class="dot">&nbsp;</a> <a href="#" class="dot">&nbsp;</a> </div> I want the three <a href="#" class="dot">&nbsp;</a> appear on the left of and the two ("Prev" and "Next") on the right. How can I do it? I tried float:left but does not work. Edit: CSS is too long to post. Development site is here at : http://site2.ewart.library.ubc.ca/

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  • Java: How can I create good looking class docs with Javadoc?

    - by Cheeso
    I'd like to create HTNML documentation for a Java class library that includes programming guide information - beyond just a class reference code examples in the reference doc collapsible regions I want it to look well-styled. Something like this: I think that Javadoc exposes a doclet API that allows other parties to provide doc generation integrated in Javadoc. Is there a doclet option that I can use (for free) that does something a little nicer than the standard javadoc output? I tried googling for this but no luck. Suggestions?

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  • How do I prevent a pair of XMLEvent[Reader|Writer] from splitting empty tags into start+end tags?

    - by java.is.for.desktop
    Hello, everyone! I have an understanding problem of how the following code works: XMLInputFactory xif = XMLInputFactory.newFactory(); XMLOutputFactory xof = XMLOutputFactory.newFactory(); XMLEventReader reader = xif.createXMLEventReader(/* ... */); XMLEventWriter writer = xof.createXMLEventWriter(/* ... */); writer.add(reader); The method writer.add([some reader]) reads all events from reader and writes them consequently. Sadly, following happens: The input <root><c/></root> gets transformed to <root><c><c/></root> I know, from XML point of view, these are equal trees, but not for a human ;) What can I do to get the same output? FYI: I need a XMLEvent[Reader|Writer] pair later to filter "XML events".

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  • How do I add a css class to the TempData output?

    - by Pete
    The TempData output is plain text and putting a div around it will leave a formatted but empty div on the screen if there is no TempData. Is there a way to apply a class to it so that it only shows when the TempData item is set? Other than writing the div code into the TempData, which seems like a horrible idea.

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  • check if a tree is complete standard ml

    - by aizen92
    I want to make a function in standard ml that checks if a tree is complete or not, the function somehow works, but its giving me the wrong type and a warning of non-exhaustive cases The tree code: datatype 'data tree = EMPTY | NODE of 'data tree * 'data * 'data tree; fun isComplete EMPTY = true | isComplete (NODE(x, y, z)) = if (x = EMPTY andalso z <> EMPTY) orelse (x <> EMPTY andalso z = EMPTY) then false else true; Now the above function's type is: ''a tree -> bool but the required type is 'a tree -> bool The warning I'm having is: stdIn:169.8 Warning: calling polyEqual stdIn:169.26 Warning: calling polyEqual stdIn:169.45-169.47 Warning: calling polyEqual stdIn:169.64-169.66 Warning: calling polyEqual stdIn:124.1-169.94 Warning: match nonexhaustive NODE (x,y,z) => ... What is the problem I'm having?

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  • Should a protected property in a C# child class hide access to a public property on the parent?

    - by Tim
    I have the following code: public class Parent { public string MyField { get; set; } } public class Child : Parent { protected new int MyField { get; set; } } I try and access this with: static void Main(string[] args) { Child child = new Child(); child.MyField = "something"; } Visual studio 2008 compiles this without comment, but under Mono (2.4.2, Ubuntu) I get the error message 'HideTest.Child.MyField' is inaccessible due to its protection level (CS0122) Is one implementation or the other more compliant with the standard here?

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  • How can I find out how much memory an object (rather the instance of an object) of a C++ class consu

    - by Shadow
    Hi, I am developing a Graph-class, based on boost-graph-library. A Graph-object contains a boost-graph, so to say an adjacency_list, and a map. When monitoring the total memory usage of my program, it consumes quite a lot (checked with pmap). Now, I would like to know, how much of the memory is exactly consumed by a filled object of this Graph-class? With filled I mean when the adjacency_list is full of vertices and edges. I found out, that using sizeof() doesn't bring me far. Using valgrind is also not an alternative as there is quite some memory allocation done previously and this makes the usage of valgrind impractical for this purpose. I'm also not interested in what other parts of the program cost in memory, I want to focus on one single object. Thank you.

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  • How to change the view if I am not present in the viewController class?

    - by wolverine
    I am doing an app with about 6-7 views and their corresponding controllers. I am in a view with a toolbar and button. When I click this button a popup view comes and my control is being moved to the popup view's Controller. But my view is still the same. From this popupview Controller's class, I want to change my original view. But since I am not in my original viewControllers class, I am not able to change it. How can I overcome this? Can anyone plz help me?

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  • What if I made an explicit reference to 'this' for use inside an inner class?

    - by badp
    So far, I've used this approach to access this from the scope of an inner class: class FooManagementWindow extends JFrame { JButton rejectFoo; //... void getFooAcceptingPanel(){ //... final FooManagementWindow referenceToThis = this; rejectFoo = new JButton("Reject"); rejectFoo.addEventListener(new EventListener() { @Override public void actionPerformed(ActionEvent arg) { referenceToThis.setEnabled(false); //this requires a network call //... referenceToThis.setEnabled(true); //the user may resume his work } }); //... } } However, I just learned that instead of declaring referenceToThis, a direct reference is kept for me as: FooManagementWindow.this I have no reason to think my less standard approach may lead to errors or weird corner cases. Or are there?

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  • How do I dynamically point an interface to a specific class at runtime?

    - by Jon
    As a simple example, I have an xml file with a list of names of classes which actually carry out the work and all implement interface IDoWork with a method Process(). I loop through the items in the xml file. How do I actually dynamically assign the class to the interface from a string name? e.g. var IDoWork = new "DoWorkType1"(); IDoWork.Process(); <work> <item id="DoWorkType1"> </item> <item id="DoWorkType2"> </item> </work> I want to achieve a plugin type architecture, except the plugin isn't at an assembly level only a class level within my program.

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  • How might you unobtrusively enhance the jQuery Datepicker class?

    - by Teflon Ted
    You can pass special strings into jQuery's Datepicker class setDate() method like "+7" which will be translated into "7 days from today": http://docs.jquery.com/UI/Datepicker#method-setDate But you can't get that "+7" back out. When you call getDate() you get the calculated resulting date. I have a use case where I need to pull out the special string "+7" for propagation. One chunk of code is passing a special string into the Datepicker and passing the Datepicker over to another chunk of code which pulls out the date, but the latter sometimes needs to know the special string rather than the calculated date. So I need to enhance the Datepicker tool to (a) store the special code internally and (b) expose it via a method like getOriginallyPassedInDate() or some such. I'm not a jQuery/Javascript ninja so I could really use some guidance on how I might preferably-unobtrusively add the necessary functionality to the Datepicker class, the way you might monkey-patch an object in Ruby I'm guessing.

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  • CSS: Centering a floated block level element in IE6 (It almost works)

    - by Louis W
    I have a block level element which I am centering on the page. I have gotten it to work for all other browsers except IE6 where it ALMOST works. http://tinyurl.com/28sh9eq If I view the page in IE6 the red box is slightly off center of the pink one in IE. If I then resize the browser window it snaps into place where I want it. Uhhhhh.... yea.... what gives? How come resizing the window makes it work? I have also tried setting an explicit width on the wrapper with no avail. <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"> <html> <head> <title></title> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <meta http-equiv="X-UA-Compatible" content="IE=7" /> <style type="text/css"> BODY { text-align: center; font-family: Arial; } .row_wrap { height: 100px; margin-bottom: 30px; background-color: pink; } .row { float: right; position: relative; left: -50%; text-align: left; clear: both; } .button1 { color: #FFF; height: 36px; text-decoration: none; position: relative; padding: 0 30px; background: url('button.gif') no-repeat 0 0; display: block; float: left; left: 50%; } .button1 .end { width: 20px; height: 37px; position: absolute; right: -2px; top: 0; background: url('button.gif') no-repeat right 0; } .button1 .text { font-size: 16px; font-weight: bold; white-space: nowrap; height: 36px; padding-top: 7px; display: block; float: left; } .button1 .text .arrow { vertical-align: 1px; } </style> </head> <body> <h2>RTL: Button 1</h2> <div class="row_wrap"> <div class="row" dir="rtl"> <a href="#" class="button1"> <span class="end"></span> <span class="text"><span class="arrow">»</span> Hello 1.</span> </a> </div> </div> <h2>RTL: Button 1-2</h2> <div class="row_wrap" style="width: 400px;"> <div class="row" dir="rtl"> <a href="#" class="button1"> <span class="end"></span> <span class="text"><span class="arrow">»</span> Hello 1.</span> </a> </div> </div> <br/><br/> <h2>Normal: Button 1</h2> <div class="row_wrap"> <div class="row"> <a href="#" class="button1"> <span class="end"></span> <span class="text"><span class="arrow">»</span> Hello.</span> </a> </div> </div> </body> Thanks for your help.

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  • Java Interfaces Methodology: Should every class implement an interface?

    - by Amir Rachum
    I've been programming in Java for a few courses in the University and I have the following question: Is it methodologically accepted that every class should implement an interface? Is it considered bad practice not to do so? Can you describe a situation where it's not a good idea to use interfaces? Edit: Personally, I like the notion of using Interfaces for everything as a methodology and habit, even if it's not clearly beneficial. Eclipse automatically created a class file with all the methods, so it doesn't waste any time anyway.

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  • How to map inheritance with property returned other inheritance?

    - by dario-g
    Hi I have abstract class Vehicle and two classes that derive from: Car and ForkLift. public abstract class Vehicle { public EngineBase Engine { get; set; } } public class Car : Vehicle { public GasEngine Engine { get; set; } } public class ForkLift : Vehicle { public ElectricEngine Engine { get; set; } } and Engine clasess: public abstract class Engine { } public class GasEngine : Engine { } public class ElectricEngine : Engine { } Engines are mapped with "table per class hierarchy". With Vehicles I want to use the same pattern. How to map Engine class and derived with that Engine property?

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