array manipulation - Page 496

Efficient data structure for fast random access, search, insertion and deletion

- by Leonel

I'm looking for a data structure (or structures) that would allow me keep me an ordered list of integers, no duplicates, with indexes and values in the same range. I need four main operations to be efficient, in rough order of importance: taking the value from a given index finding the index of a given value inserting a value at a given index deleting a value at a given index Using an array I have 1 at O(1), but 2 is O(N) and insertion and deletions are expensive (O(N) as well, I believe). A Linked List has O(1) insertion and deletion (once you have the node), but 1 and 2 are O(N) thus negating the gains. I tried keeping two arrays a[index]=value and b[value]=index, which turn 1 and 2 into O(1) but turn 3 and 4 into even more costly operations. Is there a data structure better suited for this?

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Confusion Matrix with number of classified/misclassified instances on it (Python/Matplotlib)

- by Pinkie

I am plotting a confusion matrix with matplotlib with the following code: from numpy import * import matplotlib.pyplot as plt from pylab import * conf_arr = [[33,2,0,0,0,0,0,0,0,1,3], [3,31,0,0,0,0,0,0,0,0,0], [0,4,41,0,0,0,0,0,0,0,1], [0,1,0,30,0,6,0,0,0,0,1], [0,0,0,0,38,10,0,0,0,0,0], [0,0,0,3,1,39,0,0,0,0,4], [0,2,2,0,4,1,31,0,0,0,2], [0,1,0,0,0,0,0,36,0,2,0], [0,0,0,0,0,0,1,5,37,5,1], [3,0,0,0,0,0,0,0,0,39,0], [0,0,0,0,0,0,0,0,0,0,38] ] norm_conf = [] for i in conf_arr: a = 0 tmp_arr = [] a = sum(i,0) for j in i: tmp_arr.append(float(j)/float(a)) norm_conf.append(tmp_arr) plt.clf() fig = plt.figure() ax = fig.add_subplot(111) res = ax.imshow(array(norm_conf), cmap=cm.jet, interpolation='nearest') cb = fig.colorbar(res) savefig("confmat.png", format="png") But I want to the confusion matrix to show the numbers on it like this graphic (the right one): http://i48.tinypic.com/2e30kup.jpg How can I plot the conf_arr on the graphic?

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Iphone App Similar to the Talking Larry Application

- by Zeeshan

I am developing iphone application similar to the Talking Larry Application. I am facing an issue of Low Memory when i pre-load the animations into an NSMutable Array. If i do not pre-load the animations and load it into the Animation Images when the user touch the button then it takes Time and it play back the animation very Slow. And during video making it does not play the complete animations. How can i resolve this issue. I want to play back the animations similar to the Talking Larry app and do not want to get Low Memory Issue.

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advancedDatagrid multipleSelection: Was a row already selected?

- by Werner

Hi, after multiple Selection in a advanced datagrid, I want to check if the clicked row, was already selected. Anyway my idea below (in the nested if clause I want to check if the newly clicked item's processing data is already in the added Array Collection) is not working, but I assume there must be a better way to differiante if an click was made on a already selected row. Probably I was not as clear in my description as needed, please ask your questions! Thank you very much, already in advance, Werner model.processingData = out; if (model.selectedIndices.length > 1){ //check if item already added var tempInt:int = model.multipleProcessingData.getItemIndex(model.processingData); if (tempInt == -1){ model.multipleProcessingData.addItem(model.processingData); } } else{ model.multipleProcessingData.removeAll(); model.multipleProcessingData.addItem(model.processingData); }

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problem in return value from server to client in ajax

- by user1400

hello i try to use ajax and zend framework in my application , i could pass variable to server but i can not get data from server , it does not return values, it return all html code page, where is my mistake? $('#myForm').submit(function($e){ $e.preventDefault(); var $paramToServer=$("#myForm").serialize(); $.ajax({ type:'POST', url:'test', data:$paramToServer , success:function(re){ var res = $.evalJSON(re); console.log(res.id); // to see in firebog }, dataType:'json' }); }); public function testAction() { $this->_helper->getHelper('viewRenderer')->setNoRender(); //disable layout Zend_Layout::getMvcInstance()->disableLayout(); $name=$this->getRequest()->getParam ( 'name' ); //pass $name to server $return = array( 'id' => '5', 'family' => 'hello ', ); $return = Zend_Json::encode( $return); // Response $this->getResponse()->setBody($return); }

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Zend Framework - applying order by on a nested query

- by Gublooo

Hey guys This might be a very simple thing. Check out the normal sql query below (select * from shopping order by shopping_id desc limit 5) order by RAND() This query runs successfully in mysql - not sure if this is the right way of doing it - but it works. It gets the last 5 ids from shopping table and randomly orders them everytime I want to achieve this in Zend. I'm not sure how to execute the first part and then apply the RAND clause to the results - what I have below does not do that. $select = $this-select() -from(array('sh'='shopping')) -order('shopping_id desc') -limit(5) -order('RAND()');

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vb.net Object Initialiser List(Of T)

- by Tim B James

I have been looking at some C# code: List<Employee> Employees = new List<Employee>{ new Employee{firstname="Aamir",lastname="Hasan",age=20}, new Employee{firstname="awais",lastname="Hasan",age=50}, new Employee{firstname="Bill",lastname="Hasan",age=70}, new Employee{firstname="sobia",lastname="khan",age=80}, }; Now when I convert this to vb.net Dim Employees as List(Of Employee) = New List(Of Employee)() With { New Employee() With { _ .firstname = "Aamir", _ .lastname = "Hasan", _ .age = 20 _ }, _ New Employee() With { _ .firstname = "awais", _ .lastname = "Hasan", _ .age = 50 _ }, _ New Employee() With { _ .firstname = "Bill", _ .lastname = "Hasan", _ .age = 70 _ }, _ New Employee() With { _ .firstname = "sobia", _ .lastname = "khan", _ .age = 80 _ } _ } I get the error "Name of field or property being initialized in an object initializer must start with'.'." Now I can get an array of employee using the code: Dim Employees = { New Employee() With { _ .FirstName = "Aamir", _ .LastName = "Hasan", _ .Age = 20}, _ New Employee() With { _ .FirstName = "Awais", _ .LastName = "Hasan", _ .Age = 50}, _ New Employee() With { _ .FirstName = "Bill", _ .LastName = "Hasan", _ .Age = 70 _ } _ } But I would like a List(Of Employee) as it is bugging me as to why this doesnt work in vb.net?

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Circular dependencies in StructureMap - can they be broken with property injection?

- by Andy

Hi, I've got the simplest kind of circular dependency in structuremap - class A relies on class B in its constructor, and class B relies on class A in its constructor. To break the dependency, I made class B take class A as a property, rather than a constructor argument, but structuremap still complains. I've seen circular dependencies broken using this method in other DI frameworks - is this a problem with Structuremap or am I doing something wrong? Edit: I should mention that class B's property is an array of class A instances, wired up like this: x.For<IB>().Singleton().Use<B>().Setter(y => y.ArrayOfA).IsTheDefault();

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Getting a NullPointerException at seemingly random intervals, not sure why

- by Miles

I'm running an example from a Kinect library for Processing (http://www.shiffman.net/2010/11/14/kinect-and-processing/) and sometimes get a NullPointerException pointing to this line: int rawDepth = depth[offset]; The depth array is created in this line: int[] depth = kinect.getRawDepth(); I'm not exactly sure what a NullPointerException is, and much googling hasn't really helped. It seems odd to me that the code compiles 70% of the time and returns the error unpredictably. Could the hardware itself be affecting it? Here's the whole example if it helps: // Daniel Shiffman // Kinect Point Cloud example // http://www.shiffman.net // https://github.com/shiffman/libfreenect/tree/master/wrappers/java/processing import org.openkinect.*; import org.openkinect.processing.*; // Kinect Library object Kinect kinect; float a = 0; // Size of kinect image int w = 640; int h = 480; // We'll use a lookup table so that we don't have to repeat the math over and over float[] depthLookUp = new float[2048]; void setup() { size(800,600,P3D); kinect = new Kinect(this); kinect.start(); kinect.enableDepth(true); // We don't need the grayscale image in this example // so this makes it more efficient kinect.processDepthImage(false); // Lookup table for all possible depth values (0 - 2047) for (int i = 0; i < depthLookUp.length; i++) { depthLookUp[i] = rawDepthToMeters(i); } } void draw() { background(0); fill(255); textMode(SCREEN); text("Kinect FR: " + (int)kinect.getDepthFPS() + "\nProcessing FR: " + (int)frameRate,10,16); // Get the raw depth as array of integers int[] depth = kinect.getRawDepth(); // We're just going to calculate and draw every 4th pixel (equivalent of 160x120) int skip = 4; // Translate and rotate translate(width/2,height/2,-50); rotateY(a); for(int x=0; x<w; x+=skip) { for(int y=0; y<h; y+=skip) { int offset = x+y*w; // Convert kinect data to world xyz coordinate int rawDepth = depth[offset]; PVector v = depthToWorld(x,y,rawDepth); stroke(255); pushMatrix(); // Scale up by 200 float factor = 200; translate(v.x*factor,v.y*factor,factor-v.z*factor); // Draw a point point(0,0); popMatrix(); } } // Rotate a += 0.015f; } // These functions come from: http://graphics.stanford.edu/~mdfisher/Kinect.html float rawDepthToMeters(int depthValue) { if (depthValue < 2047) { return (float)(1.0 / ((double)(depthValue) * -0.0030711016 + 3.3309495161)); } return 0.0f; } PVector depthToWorld(int x, int y, int depthValue) { final double fx_d = 1.0 / 5.9421434211923247e+02; final double fy_d = 1.0 / 5.9104053696870778e+02; final double cx_d = 3.3930780975300314e+02; final double cy_d = 2.4273913761751615e+02; PVector result = new PVector(); double depth = depthLookUp[depthValue];//rawDepthToMeters(depthValue); result.x = (float)((x - cx_d) * depth * fx_d); result.y = (float)((y - cy_d) * depth * fy_d); result.z = (float)(depth); return result; } void stop() { kinect.quit(); super.stop(); } And here are the errors: processing.app.debug.RunnerException: NullPointerException at processing.app.Sketch.placeException(Sketch.java:1543) at processing.app.debug.Runner.findException(Runner.java:583) at processing.app.debug.Runner.reportException(Runner.java:558) at processing.app.debug.Runner.exception(Runner.java:498) at processing.app.debug.EventThread.exceptionEvent(EventThread.java:367) at processing.app.debug.EventThread.handleEvent(EventThread.java:255) at processing.app.debug.EventThread.run(EventThread.java:89) Exception in thread "Animation Thread" java.lang.NullPointerException at org.openkinect.processing.Kinect.enableDepth(Kinect.java:70) at PointCloud.setup(PointCloud.java:48) at processing.core.PApplet.handleDraw(PApplet.java:1583) at processing.core.PApplet.run(PApplet.java:1503) at java.lang.Thread.run(Thread.java:637)

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Efficient heaps in purely functional languages

- by Kim

As an exercise in Haskell, I'm trying to implement heapsort. The heap is usually implemented as an array in imperative languages, but this would be hugely inefficient in purely functional languages. So I've looked at binary heaps, but everything I found so far describes them from an imperative viewpoint and the algorithms presented are hard to translate to a functional setting. How to efficiently implement a heap in a purely functional language such as Haskell? Edit: By efficient I mean it should still be in O(n*log n), but it doesn't have to beat a C program. Also, I'd like to use purely functional programming. What else would be the point of doing it in Haskell?

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Binding the property to a control defined inside a listboxitem template

- by Malcolm

I have a class called ledgerObject : public class LedgerObject { public ChargeLine ChargeLine{ get; set; } public DelegateCommand Click_hyperbnCommand{ get; private set; } public LedgerObject() { this.Click_hyperbnCommand = new DelegateCommand(click_btn); } private void click_btn(object args) { } } The chargeLine which is the property of this class is itself a class and has some properties in it. So I am binding the datacontext of a listbox to an array of LedgerObject, and I want to bind the textblock control defined inside a listboxitem template to the property of a ChargeLine. Any idea or suggestion will help. I have tried this but not working: <TextBlock Margin="4 0 4 0" Grid.Column="3" Text="{Binding Path=ChargeLine.SimCode}" TextDecorations="Underline" Foreground="Red" />

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Write wave files to memory in Java

- by Cliff

I'm trying to figure out why my servlet code creates wave files with improper headers. I use: AudioSystem.write( new AudioInputStream( new ByteArrayInputStream(memoryBytes), new AudioFormat(22000, 16, 1, true,false), memoryBytes.length ), AudioFileFormat.Type.WAVE, servletOutputStream ); taking a byte array from memory containing raw PCM samples and a servlet output stream that gets returned to the client. In the result I get a normal wave file but with zeros in the chunk size fields. Is the API broken? I would think that the size could be filled in using the size passed in the audio input stream. But now, after typing this out I'm thinking its not making this info available to the outer write() method on AudioSystem. It seems like the AudioSystem.write call needs a size parameter unless it is able to pull the size from the stream... which wouldn't work with an arbitrary sized stream. Does anyone know how to make this example work?

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Easiest Way to Parse data from twitter with Coccoa

- by happyCoding25

Hello, Im followed the tutorial from here: Twitter Client Tutorial to make a little twitter app. Now I need to find out how to parse the XML twitter gives you when you make a request. I've looked at tons of tutorials on phrasing xml on the iPhone but none have made much sense because Im still new to cocoa. Twitter stores the text of the tweet in something like this <text> Some tweet here </text>. From reading the tutorials I think this would involve nsxmlparser but I'm not sure. If anyone could share some code that could parse the <text> Some tweet here </text> things into an array that would be really great. Thanks in advance

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Binding output of Custom Activity designer to activity argument

- by gbanfill

I am trying to add a custom activity designer for an activity that I have. The activity looks a little like: public class WaitForUserInputActvitiy : NativeActivity { public InArgument<UserInteractionProperty[]> UserInteraction { get; set; } } I am trying to put a designer on the activity to make it a bit nicer to set these values (so you don't end up typing VB in directly. My designer is based on mindscape property grid. I have an ObservableDictionary source that I want to get the values from and put them in to the InArgument. Currently I am using private void TestGrid_LostFocus(object sender, RoutedEventArgs e) { using (ModelEditingScope editingScope = this.ModelItem.BeginEdit()) { Argument myArg = Argument.Create(typeof(WaitForUserInputActvitiy), ArgumentDirection.In); this.ModelItem.Properties["UserInteraction"].SetValue(source.Values.ToArray()); editingScope.Complete(); } } However this results in an ArgumentException "Object of type UserInteractionProperty[] cannot be converted to InArgument`1[UserInteractionProperty[]]. So how do I convert my array of UserInteractionProperties into an InArgument?

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exception 'Zend_Controller_Action_Exception' with message 'Action "index" does not exist and was not

- by princyp

Anyone know what this error means? after googling I found a bunch of sites that appear to have the same error? thanks exception 'Zend_Controller_Action_Exception' with message 'Action "index" does not exist and was not trapped in __call()' in /usr/local/zend/apache2/htdocs/pintsy/lib/Zend/Controller/Action.php:485 Stack trace: #0 /usr/local/zend/apache2/htdocs/pintsy/lib/Zend/Controller/Action.php(515): Zend_Controller_Action->__call('indexAction', Array) #1 /usr/local/zend/apache2/htdocs/pintsy/lib/Zend/Controller/Dispatcher/Standard.php(289): Zend_Controller_Action->dispatch('indexAction') #2 /usr/local/zend/apache2/htdocs/pintsy/lib/Zend/Controller/Front.php(946): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http)) #3 /usr/local/zend/apache2/htdocs/pintsy/html/index.php(114): Zend_Controller_Front->dispatch() #4 {main}

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Thoughts/Input about Database Design for a CMS

- by dallasclark

I'm just about to expand the functionality of our own CMS but was thinking of restructuring the database to make it simpler to add/edit data types and values. Currently, the CMS is quite flat - the CMS requires a field in the database for every type of stored value (manually created). The first option that comes to mind is simply a table which keeps the data types (ie: Address 1, Suburb, Email Address etc) and another table which holds values for each of these data types. Just like how Wordpress keeps values in the 'options' table, PHP serialize would be used to store an array of values. The second option is how Drupal works, the CMS creates tables for every data type. Unlike Wordpress, this can be a bit of an overkill but really useful for SQL queries when ordering and grouping by a particular value. What's everyone's thoughts?

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set Image to Button

- by Ivan

Hello all, Could somebody help me a little bit with my issue below? When I call the myFunction, images which I want to set to buttons appear after 2 sec simultaneously, not one by one with delay of 0.5 sec. More info: generatedNumbers is array with four elements of NSNumber (4,1,3,2) buttons are set in UIView via IB and are tagged (1,2,3,4) -(IBAction) myFunction:(id) sender { int i, value; for (i = 0; i<[generatedNumbers count]; i++) { value = [[generatedNumbers objectAtIndex:i] intValue]; UIButton *button = (UIButton *)[self.view viewWithTag:i+1]; UIImage *img = [UIImage imageNamed:[NSString stringWithFormat:@"%d.png",value]]; [button setImage:img forState:UIControlStateNormal]; [img release]; usleep(500000); } }

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Using JSON, passing variable from php to javascript

- by Ryan Fung

I wonder why it is not working? check_login.php <?php session_start(); $data = array("username" => "true"); echo json_encode($data); ?> my js file var linkName; $.ajax({ type: "POST", url: "check_login.php", dataType: "json", success: function(json){ if(json.username != "true") { //do something } } }); I am trying to get the username after checking whether or not the user has signed in yet in the php file, something like passing a session variable. But currently passing a string seems to already have a problem. Any know what I did wrong here? Still not working the code above. Anyone want to help me out here?

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Increment global variable on click in flash, actionscript 3

- by msandbot

Hi, Making a flash page that can cycle through these three images on mouseclick. For some reason the local changes to count are not reflected on the global one. I tried _global but the syntax was odd and gave me errors. How should I implement this? import flash.events.Event; var images:Array = ["images/image.jpg", "images/image2.jpg", "images/image3.jpg"]; var count:int = 0; forward.addEventListener(MouseEvent.CLICK, loadPhoto); function loadPhoto(evt:Event){ if(count>2){ count==0; } trace(count); imageFrame.source = images[count]; count++; }

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Multiple ParticleSystems in cocos2d

- by Mattias Akerman

I wonder about what road I should go with ParticleSystem. In this particular case I want to create 1-20 small explosions at the same time but with different positions. Right now I'm creating a new ParticleSystem for each explosion and then release it, but of course this is very punishing to the performance. My question is: Is there a way to create one ParticleSystem with multiple emitting sources. If not should I create an array of ParticleSystem in init and then use a free one when an explosion is needed? Or is there another approach I haven't thought of?

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Is POSTing a Dictionary to an .NET MVC action possible?

- by Brenton Alker

I have a form which contains a series of fields like: <input type="text" name="User[123]" value="Alice" /> <input type="text" name="User[456]" value="Bob" /> ... Where the index of the User array (123 and 456) are ID's associated with the value. I'm trying to update these values in the controller. My thinking is that a Dictionary that maps ID to name would work, but creating the action like: public void Save(Dictionary<string, string> user) { // ... } results in the user parameter being null. So, is passing a Dictionary possible? or, is there another method to achieve this?

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Match returning a string instead of object

- by Pablo

This simple regex matching returns a string instead of an object on every browser but the latest firefox... text = "language. Filename: My Old School Yard.avi. File description: File size: 701.54 MB. View on Megavideo. Enter this, here:" name = text.match(/(Filename:)(.*) File /); alert(typeof(name)); as far as i know this the match function is suppose to return an object (Array). Has anyone come across this issue?

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How do I determine if a packet is RTP/RTCP?

- by Chris Holmes

I am using SharpPCap which is built on WinPCap to capture UDP traffic. My end goal is to capture the audio data from H.323 and save those phone conversations as WAV files. But first thing is first - I need to figure out what my UDP packets are crossing the NIC. SharpPCap provides a UdpPacket class that gives me access to the PayloadData of the message. But I am unsure what do with this data. It's a Byte[] array and I don't know how to go about determining if it's an RTP or RTCP packet. I've Googled this topic but there isn't much out there. Any help is appreciated.

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Android simple question

- by Josemalive

Hi, I have an android application that shows a grid view that shows: 1 2 3 4 GridView gridview=(GridView)findViewById(R.id.GridView_test); DataBaseHelper dbhelper=new DataBaseHelper(this); ArrayList<String> test=new ArrayList<String>(5); backlinksadapter.add("1"); backlinksadapter.add("2"); backlinksadapter.add("3"); backlinksadapter.add("4"); ArrayAdapter mAdapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, test); gridview.setAdapter(mAdapter); By the moment is working, but i would like to show foreach line of the grid, 2 columns with the values of a 2 dimensional array (something like the GridView in ASP.Net - as datasource -). I would like to show: 1 | Person 1 2 | Person 2 3 | Person 3 4 | Person 4 Any idea? Thanks in advance. Jose.

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Extended with advice: Moving block wont work in Javascript

- by Mack

Hello Note: this is an extension of a question I just asked, i have made the edits & taken the advice but still no luck I am trying to make a webpage where when you click a link, the link moves diagonally every 100 milliseconds. So I have my Javascript, but right now when I click the link nothing happens. I have run my code through JSLint (therefore changed comaprisions to === not ==, thats weird in JS?). I get this error from JSLink though: Error: Implied global: self 15,38, document 31 What do you think I am doing wrong? <script LANGUAGE="JavaScript" type = "text/javascript">  </script> <style type="text/css" media="all">  </style>

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Search found 16413 results on 657 pages for 'array manipulation'.

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- by user1400

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- by Malcolm

- by Cliff

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- by Pablo

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