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  • Why does Python array moduel handle strings and lists differently?

    - by Casey
    I'm having trouble understanding the result of the following statements: >>> from array import array >>> array('L',[0xff,0xff,0xff,0xff]) array('L', [255L, 255L, 255L, 255L]) >>> from array import array >>> array('L','\xff\xff\xff\xff') Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: string length not a multiple of item size

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  • BizTalk 2009 - Size Functoid Fun

    - by StuartBrierley
    Recently when mapping a flat file from a third party source, I needed to check whether some elements had been sent with any content or not. In the source message these elements were being supplied in the form: <comment /> I though I would try using the size functoid, assuming that it would return a size of 0 for these empty elements.  What actully happens is that the Size funtoid returned a size of 1 rather than the 0 I was expecting. To get what I considered to be the correct output I needed to add a String Right Trim functoid before the Size functoid.  This then returned the "required" size of 0.

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  • Java HTTP Requests Buffer size

    - by behrk2
    Hello, I have an HTTP Request Dispatcher class that works most of the time, but I had noticed that it "stalls" when receiving larger requests. After looking into the problem, I thought that perhaps I wasn't allocating enough bytes to the buffer. Before, I was doing: byte[] buffer = new byte[10000]; After changing it to 20000, it seems to have stopped stalling: String contentType = connection.getHeaderField("Content-type"); ByteArrayOutputStream baos = new ByteArrayOutputStream(); InputStream responseData = connection.openInputStream(); byte[] buffer = new byte[20000]; int bytesRead = responseData.read(buffer); while (bytesRead > 0) { baos.write(buffer, 0, bytesRead); bytesRead = responseData.read(buffer); } baos.close(); connection.close(); Am I doing this right? Is there anyway that I can dynamically set the number of bytes for the buffer based on the size of the request? Thanks...

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  • How do the size standard libraries compare for different languages

    - by Roman A. Taycher
    Someone was recently raving about how great jQuery was and how it made javascript into a pleasure and also how the whole source code was so small(and one file). I looked it up on www.ohloh.net/ and it said it was about 30,000 lines of javascript, when I tired curl piped to wc it said about 5000 lines(strange discrepancy that, maybe test suites, ect?). I thought well it isn't that strange since javascript from what I've heard has a lot of fun dynamic tricks, so you can probably get away with a small library. But then I thought what about other high level languages, the ones with large standard libraries and wondered how big the standard are for python/ruby/haskell/pharo(smalltalk)/*ml/ect. (libraries not vm stuff to the degree its possible to separate it) Anybody know? Any details (comment/blank/code lines , test code lines, lines in language vs lines in ffi/byte-code) are appreciated! edit: ps. since it started this me asking about jQuery as a bonus if you could please list the size of mega frameworks, a megaframewok provides so much that people using an x megaframework in language y might sometimes refer to programming in xy or even x rather then in y (ie. : qt, jQuery, etc.).

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  • Popup window size in android

    - by Bostjan
    I'm creating a popup window in a listactivity in the event onListItemClick. LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); View pop = inflater.inflate(R.layout.popupcontact, null, false); ImageView atnot = (ImageView)pop.findViewById(R.id.aNot); height = pop.getMeasuredHeight(); width = pop.getMeasuredWidth(); Log.e("pw","height: "+String.valueOf(height)+", width: "+String.valueOf(width)); atnot.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { pw.dismiss(); } }); pw = new PopupWindow(pop, width, height, true); // The code below assumes that the root container has an id called 'main' //pw.showAtLocation(v, Gravity.CENTER, 0, 0); pw.showAsDropDown(v, 10, 5); Now, the height and width variables were supposed to be height and width of the layout used for the popup window (popupcontact). But they return 0. I guess that is because the layout isn't rendered yet. Does anyone have a clue, how can I control the size of the popup window without needing to use absolute pixel numbers?

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  • How to accurately resize nested elements with ems and font-size percentage?

    - by moonDogDog
    I have a carousel with textboxes for each image, and my client (who knows nothing about HTML) edits the textboxes using a WYSIWYG text editor. The resulting output is akin to your worst nightmares; something like: <div class="carousel-text-container"> <span style="font-size:18pt;"> <span style="font-weight:bold;"> Lorem <span style="font-size:15pt:">Dolor</span> </span> Ipsum <span style="font-size:19pt;"><span>&nbsp;<span>Sit</span>Amet</span> </span> </div> This site has to be displayed at 3 different sizes to accomodate smaller monitors, so I have been using CSS media queries to resize the site. Now I am having trouble resizing the text inside the textbox correctly. I have tried using jQuery.css to get the font size of each element in px, and then convert it to em. Then, by setting a font-size:x% sort of declaration on .carousel-text-container, I hoped that that would resize everything properly. Unfortunately, there seems to be a recursive nature with how font-size is applied in ems. That is, .example is not resized properly in the following because its parent is also influencing it <span style="font-size:2em;"> Something <span class="example" style="font-size:1.5em;">Else</span> </span> How can I resize everything reliably and precisely such I can achieve a true percentage of my original font size, margin, padding, line-height, etc. for all the children of .carousel-text-container?

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  • How do I get the size of the boost buffer

    - by Anonymous
    I am trying to make an asynchronised server in visual studio and I use boost::asio::async_read(m_socket, boost::asio::buffer(m_buffer), boost::bind(&tcp_connection::handle_read, shared_from_this(), boost::asio::placeholders::error)); to get the buffer to be put in m_buffer boost::array<char, 256> m_buffer; but how do I get the size of this thing, m_buffer? size() didn't work, end() didn't work.. Any help would be fantastic. Thanks in advance.

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  • How can I get size in bytes of an object sent using RMI?

    - by Lucas Batistussi
    I'm implementing a cache server with MongoDB and ConcurrentHashMap java class. When there are available space to put object in memory, it will put at. Otherwise, the object will be saved in a mongodb database. Is allowed that user specify a size limit in memory (this should not exceed heap size limit obviously!) for the memory cache. The clients can use the cache service connecting through RMI. I need to know the size of each object to verify if a new incoming object can be put into memory. I searched over internet and i got this solution to get size: public long getObjectSize(Object o){ try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(o); oos.close(); return bos.size(); } catch (Exception e) { return Long.MAX_VALUE; } } This solution works very well. But, in terms of memory use doesn't solve my problem. :( If many clients are verifying the object size at same time this will cause stack overflow, right? Well... some people can say: Why you don't get the specific object size and store it in memory and when another object is need to put in memory check the object size? This is not possible because the objects are variable in size. :( Someone can help me? I was thinking in get socket from RMI communication, but I don't know how to do this...

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  • Array not showing in Jlist but filled in console

    - by OVERTONE
    Hey there. been a busy debugger today. ill give ths short version. ive made an array list that takes names from a database. then i put the contents of the arraylist into an array of strings. now i want too display the arrays contents in a JList. the weird thing is it was working earlier. and ive two methods. ones just a little practice too make sure i was adding to the Jlist correctly. so heres the key codes. this is the layout of my code. variables constructor methods in my variables i have these 3 defined String[] contactListNames = new String[5]; ArrayList<String> rowNames = new ArrayList<String>(); JList contactList = new JList(contactListNames); simple enough. in my constructor i have them again. contactListNames = new String[5]; contactList = new JList(contactListNames); //i dont have the array list defined though. printSqlDetails(); // the prinSqldetails was too make sure that the connectionw as alright. and its working fine. fillContactList(); // this is the one thats causing me grief. its where all the work happens. // fillContactListTest(); // this was the tester that makes sure its adding to the list alright. heres the code for fillContactListTest() public void fillContactListTest() { for(int i = 0;i<3;i++) { try { String contact; System.out.println(" please fill the list at index "+ i); Scanner in = new Scanner(System.in); contact = in.next(); contactListNames[i] = contact; in.nextLine(); } catch(Exception e) { e.printStackTrace(); } } } heres the main one thats supposed too work. public void fillContactList() { int i =0; createConnection(); ArrayList<String> rowNames = new ArrayList<String>(); try { Statement stmt = conn.createStatement(); ResultSet namesList = stmt.executeQuery("SELECT name FROM Users"); try { while (namesList.next()) { rowNames.add(namesList.getString(1)); contactListNames =(String[])rowNames.toArray(new String[rowNames.size()]); // this used to print out contents of array list // System.out.println("" + rowNames); while(i<contactListNames.length) { System.out.println(" " + contactListNames[i]); i++; } } } catch(SQLException q) { q.printStackTrace(); } conn.commit(); stmt.close(); conn.close(); } catch(SQLException e) { e.printStackTrace(); } } i really need help here. im at my wits end. i just cant see why the first method would add to the JList no problem. but the second one wont. both the contactListNames array and array list can print fine and have the names in them. but i must be transfering them too the jlist wrong. please help p.s im aware this is long. but trust me its the short version.

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  • Get user profile size in vbscript

    - by Cameron
    Hello, I am trying to get the size of a user's local profile using VBScript. I know the directory of the profile (typically "C:\Users\blah"). The following code does not work for most profiles (Permission Denied error 800A0046): Dim folder Dim fso Set fso = WScript.CreateObject("Scripting.FileSystemObject") Set folder = fso.GetFolder("C:\Users\blah") MsgBox folder.Size ' Error occurs here Is there another way to do this? UPDATE: I did some deeper digging and it turns out that the Permission Denied error occurs if permission is denied to some subfolders or files of the directory whose size I wish to get. In the case of user profiles, there's always a few system files that even the Administrator group does not have permission to access. To get around this, I wrote a function that tries to get the folder size the normal way (above), then, if the error occurs, it recurses into the subdirectories of the folder, ignoring folder sizes that are permission denied (but not the rest of the folders). Dim fso Set fso = WScript.CreateObject("Scripting.FileSystemObject") Function getFolderSize(folderName) On Error Resume Next Dim folder Dim subfolder Dim size Dim hasSubfolders size = 0 hasSubfolders = False Set folder = fso.GetFolder(folderName) ' Try the non-recursive way first (potentially faster?) Err.Clear size = folder.Size If Err.Number <> 0 then ' Did not work; do recursive way: For Each subfolder in folder.SubFolders size = size + getFolderSize(subfolder.Path) hasSubfolders = True Next If not hasSubfolders then size = folder.Size End If End If getFolderSize = size Set folder = Nothing ' Just in case End Function

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  • Set List View Size Android

    - by Sandeep
    Hello , I am using List View in my project where i have used a xml file which is used to create the list item.Then i have used it programmatically in my class which is extended by ListActivity. But the problem is i have to add a button in the bottom of screen which is not related to list view but List view covers all the screen. So,is there any way to add button in bottom with list view in android. My Code is :- import android.app.ListActivity; import android.content.Intent; import android.os.Bundle; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ImageView; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; import android.widget.AdapterView.OnItemClickListener; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.Window; public class Options extends ListActivity { String[] items; @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); requestWindowFeature(Window.FEATURE_RIGHT_ICON); items = getResources().getStringArray(R.array.chantOption_array); setListAdapter(new IconicAdapter()); ListView lv = getListView(); lv.setTextFilterEnabled(true); lv.setBackgroundResource(R.drawable.ichant_logo); setFeatureDrawableResource(Window.FEATURE_RIGHT_ICON, R.drawable.icon_t); lv.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // When clicked, show a toast with the TextView text Toast.makeText(getApplicationContext(), items[position], Toast.LENGTH_SHORT).show(); if ("Gayatri Mantra".equals(items[position].toString())) { int[] timeintervals = { 23900, 24000 }; // startChantActivity(TotalMala_loop,Total_Bead_Loop,BacgroundImage,Icon,Title,BeadsTotalTimeIntervals+totalTimeDurationOfAudio) startChantActivity(2, 108, R.drawable.gayatri, R.raw.gayatri, R.drawable.icon_gayatri, "Gayatri Mantra", timeintervals); } if ("Om Mani Padme Hum".equals(items[position].toString())) { int[] timeintervals = { 5500, 8200, 11100, 13900, 34100, 36700, 39500, 42300, 59300, 62000, 64800, 67600, 124600 }; // startChantActivity(TotalMala_loop,Total_Bead_Loop,BacgroundImage,Icon,Title,BeadsTotalTimeIntervals+totalTimeDurationOfAudio) startChantActivity(2, 108, R.drawable.ommanipadmehum, R.raw.om_mani, R.drawable.icon_padme, "Om Mani Padme Hum", timeintervals); } if ("Sai Ram".equals(items[position].toString())) { // Audio time interval for bead+total time duration of audio int[] timeintervals = { 4800, 7500, 10400, 12600, 15800, 18600, 21600, 24400, 25000 }; // startChantActivity(TotalMala_loop,Total_Bead_Loop,BacgroundImage,Icon,Title,BeadsTotalTimeIntervals+totalTimeDurationOfAudio) startChantActivity(2, 108, R.drawable.sairam, R.raw.sairam, R.drawable.icon_sairam, "Sai Ram", timeintervals); } if ("Aum".equals(items[position].toString())) { // Audio time interval for bead+total time duration of audio int[] timeintervals = { 12850, 13000 }; // startChantActivity(TotalMala_loop,Total_Bead_Loop,BacgroundImage,Icon,Title,BeadsTotalTimeIntervals+totalTimeDurationOfAudio) startChantActivity(2, 108, R.drawable.aum, R.raw.aum, R.drawable.ico_aum, "Aum", timeintervals); } } }); } class IconicAdapter extends ArrayAdapter { IconicAdapter() { super(Options.this, R.layout.list_item, items); } public View getView(int position, View convertView, ViewGroup parent) { LayoutInflater inflater = getLayoutInflater(); View row = inflater.inflate(R.layout.list_item, parent, false); TextView label = (TextView) row.findViewById(R.id.label); label.setText(" "+items[position]); ImageView icon = (ImageView) row.findViewById(R.id.icon); if (items[position].equals("Gayatri Mantra")) { icon.setImageResource(R.drawable.icon_gayatri); } if (items[position].equals("Om Mani Padme Hum")) { icon.setImageResource(R.drawable.icon_padme); } if (items[position].equals("Sai Ram")) { icon.setImageResource(R.drawable.icon_sairam); } if (items[position].equals("Aum")) { icon.setImageResource(R.drawable.ico_aum); } return (row); } } protected void startChantActivity(int mala_loop, int beads_loop, int background, int media, int titleIcon, String title, int[] timeintervals) { Bundle bundle = new Bundle(); bundle.putInt("mala_loop", mala_loop); bundle.putInt("beads_loop", beads_loop); bundle.putInt("background", background); bundle.putInt("media", media); bundle.putInt("titleIcon", titleIcon); bundle.putString("title", title); bundle.putIntArray("intervals", timeintervals); Intent intent = new Intent(this, ChantBliss.class); intent.putExtras(bundle); startActivityForResult(intent, this.getSelectedItemPosition()); } } And Corresponding xml file is: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" > <ImageView android:id="@+id/icon" android:layout_width="wrap_content" android:paddingLeft="2px" android:paddingRight="2px" android:paddingTop="2px" android:layout_height="wrap_content" /> <TextView android:id="@+id/label" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="22sp" android:textColor="#ff000000" /> </LinearLayout> Thanks in Advance: Sandeep

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  • Warning: array_multisort() [function.array-multisort]: Argument #1 is expected to be an array or a

    - by johnny
    Hi, the following code produces the error in the title. I've tried to google it, but all I got were pages who got the same error (and not an explanation thereof). This isn't really a problem since it's actually working and cancelling the error out with the @ works out just fine. Though I'm still wondering why I haven't been able to execute array_multisort just once without getting this error. public function getMostRelevant(){ list($occurrences, $keywords) = $this->occurr_keyw_array; array_multisort($occurrences, SORT_DESC, SORT_NUMERIC, $keywords); $return_array = array( array($occurrences[0], $keywords[0]), array($occurrences[1], $keywords[1]), array($occurrences[2], $keywords[2]) ); return $return_array; }

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  • Multidimensional array with unequal second dimension size using malloc()

    - by user288422
    Hello, I am playing around with multidimensional array of unequal second dimension size. Lets assume that I need the following data structure: [&ptr0]-[0][1][2][3][4][5][6][7][8][9] [&ptr1]-[0][1][2] [&ptr2]-[0][1][2][3][4] int main() { int *a[3]; int *b; int i; a[0] = (int *)malloc(10 * sizeof(int)); a[1] = (int *)malloc(2 * sizeof(int)); a[2] = (int *)malloc(4 * sizeof(int)); for(i=0; i<10; i++) a[0][i]=i; for(i=0; i<2; i++) a[1][i]=i; for(i=0; i<4; i++) a[2][i]=i; } I did some tests and it seems like I can store a value at a[1][3]. Does it mean that rows in my array are of equal size 10?

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  • append a numpy array to a numpy array

    - by Fraz
    I just started programming in python and am very new to numpy packages.. so still trying to get a hang of it. I have a an numpy_array so something like [ a b c] And then I want to append it into anotehr numpyarray (Just like we create a list of lists) How do we create an array of numpy arrays containing numpy arrays I tried to do the following without any luck >>> M = np.array([]) >>> M array([], dtype=float64) >>> M.append(a,axis=0) Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'numpy.ndarray' object has no attribute 'append' >>> a array([1, 2, 3])

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  • Numpy: Sorting a multidimensional array by a multidimensional array

    - by JD Long
    Forgive me if this is redundant or super basic. I'm coming to Python/Numpy from R and having a hard time flipping things around in my head. I have a n dimensional array which I want to sort using another n dimensional array of index values. I know I could wrap this in a loop but it seems like there should be a really concise Numpyonic way of beating this into submission. Here's my example code to set up the problem where n=2: a1 = random.standard_normal(size=[2,5]) index = array([[0,1,2,4,3] , [0,1,2,3,4] ]) so now I have a 2 x 5 array of random numbers and a 2 x 5 index. I've read the help for take() about 10 times now but my brain is not groking it, obviously. I thought this might get me there: take(a1, index) array([[ 0.29589188, -0.71279375, -0.18154864, -1.12184984, 0.25698875], [ 0.29589188, -0.71279375, -0.18154864, 0.25698875, -1.12184984]]) but that's clearly reordering only the first element (I presume because of flattening). Any tips on how I get from where I am to a solution that sorts element 0 of a1 by element 0 of the index ... element n?

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  • jquery add to an array on click?

    - by KittyYoung
    I'm confused regarding each() and .each()... I think I need to use both, but I'm not sure how... Basically, I have a series of checkboxes and when they're checked, I want to get the id of the closest table row and add it to an array that I can then serialize and pass to a function. So, the html looks like this: <tr id="t1"><td><input type="checkbox" name="did[]" value="232" class="bd" /></td></tr> <tr id="t2"><td><input type="checkbox" name="did[]" value="234" class="bd" /></td></tr> <tr id="t3"><td><input type="checkbox" name="did[]" value="676" class="bd" /></td></tr> <tr><td><button id="tsid" name="tsid" type="button">Send</button></td></tr> And, when (and if) the checkbox is selected, I want to get the closest tr id and store it in an array: var trids = [] And then serialize the input data and the trids array... So far, I only have this: $('#tsid').click(function() { //meant to get the values of the selected checkboxes var myData = $('input[name=did[]]').serialize(); //meant to find and store the closest tr ids in an array... $('.bd').each(function() { var trids = $(this).closest("tr").get(0); //and now I'm lost... }); }

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  • AS3: Array of objects parsed from XML remains with zero length

    - by Joel Alejandro
    I'm trying to parse an XML file and create an object array from its data. The data is converted to MediaAlbum classes (class of my own). The XML is parsed correctly and the object is loaded, but when I instantiate it, the Albums array is of zero length, even when the data is loaded correctly. I don't really know what the problem could be... any hints? import Nem.Media.*; var mg:MediaGallery = new MediaGallery("test.xml"); trace(mg.Albums.length); MediaGallery class: package Nem.Media { import flash.net.URLRequest; import flash.net.URLLoader; import flash.events.*; public class MediaGallery { private var jsonGalleryData:Object; public var Albums:Array = new Array(); public function MediaGallery(xmlSource:String) { var loader:URLLoader = new URLLoader(); loader.load(new URLRequest(xmlSource)); loader.addEventListener(Event.COMPLETE, loadGalleries); } public function loadGalleries(e:Event):void { var xmlData:XML = new XML(e.target.data); var album; for each (album in xmlData.albums) { Albums.push(new MediaAlbum(album.attribute("name"), album.photos)); } } } } XML test source: <gallery <albums <album name="Fútbol 9" <photos <photo width="600" height="400" filename="foto1.jpg" / <photo width="600" height="400" filename="foto2.jpg" / <photo width="600" height="400" filename="foto3.jpg" / </photos </album <album name="Fútbol 8" <photos <photo width="600" height="400" filename="foto4.jpg" / <photo width="600" height="400" filename="foto5.jpg" / <photo width="600" height="400" filename="foto6.jpg" / </photos </album </albums </gallery

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  • How to print a Perl 2-dimensional array?

    - by Matt Pascoe
    I am trying to write a simple Perl script that reads a *.csv, places the rows of the *.csv file in a two dimensional array, and then prints on item out of the array and then prints a row of the array. #!/usr/bin/perl use strict; use warnings; open(CSV, $ARGV[0]) || die("Cannot open the $ARGV[0] file: $!"); my @row; my @table; while(<CSV>) { @row = split(/\s*,\s*/, $_); push(@table, @row); } close CSV || die $!; foreach my $element ( @{ $table[0] } ) { print $element, "\n"; } print "$table[0][1]\n"; When I run this script I receive the following error and nothing prints: Can't use string ("1") as an ARRAY ref while "strict refs" in use at ./scripts.pl line 16. I have looked in a number of other forums and am still not sure how to fix this issue. Can anyone help me fix this script?

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  • How do I set an array in one class with another array in another class

    - by Stef
    I've populated and array with data like this in one class... PowerClass.h NSMutableArray pickerArray; @property (nonatomic, retain) NSMutableArray pickerArray; - PowerClass.m @synthesize pickerArray; @implementation NSMutableArray *array = [[NSArray alloc] initWithObjects:@"stef", @"steve", @"baddamans", @"jonny", nil]; pickerArray = [NSMutableArray arrayWithArray:array]; And I'm trying to set the Array in another class WeekClass.h PowerClass *powerClass; NSMutableArray *pickerData; @property (nonatomic, retain) NSMutableArray pickerData; @property (nonatomic, retain) PowerClass *powerClass; WeekClass.m @implementation pickerData = [NSMutableArray arrayWithArray:powerClass.pickerArray]; I have no errors or warnings. It just crashes. The NSLog says that the powerClass.pickerArray is NULL. Please help point me in the right direction.

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  • Double associative array or indexed + associative array

    - by clover
    I'm undecided what's the best-practice approach for what I'm trying to do. I'm trying to enter data into an array where the data will look like this: apple color: red price: 2 orange color: orange price: 3 banana color: yellow price: 2 pineapple color: yellow price: 5 When I get input, let's say green apple (notice it's a combo of color + name of fruit), I'm going to check if the name of fruit part exists in the array and display its data (if it exists). What's the right way to compose those arrays? How would I do an indexed array containing an associative array? (or would this be better as 2 nested associative arrays, I'm guessing not)

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  • Performance question: Inverting an array of pointers in-place vs array of values

    - by Anders
    The background for asking this question is that I am solving a linearized equation system (Ax=b), where A is a matrix (typically of dimension less than 100x100) and x and b are vectors. I am using a direct method, meaning that I first invert A, then find the solution by x=A^(-1)b. This step is repated in an iterative process until convergence. The way I'm doing it now, using a matrix library (MTL4): For every iteration I copy all coeffiecients of A (values) in to the matrix object, then invert. This the easiest and safest option. Using an array of pointers instead: For my particular case, the coefficients of A happen to be updated between each iteration. These coefficients are stored in different variables (some are arrays, some are not). Would there be a potential for performance gain if I set up A as an array containing pointers to these coefficient variables, then inverting A in-place? The nice thing about the last option is that once I have set up the pointers in A before the first iteration, I would not need to copy any values between successive iterations. The values which are pointed to in A would automatically be updated between iterations. So the performance question boils down to this, as I see it: - The matrix inversion process takes roughly the same amount of time, assuming de-referencing of pointers is non-expensive. - The array of pointers does not need the extra memory for matrix A containing values. - The array of pointers option does not have to copy all NxN values of A between each iteration. - The values that are pointed to the array of pointers option are generally NOT ordered in memory. Hopefully, all values lie relatively close in memory, but *A[0][1] is generally not next to *A[0][0] etc. Any comments to this? Will the last remark affect performance negatively, thus weighing up for the positive performance effects?

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  • ArrayAccess multidimensional (un)set?

    - by anomareh
    I have a class implementing ArrayAccess and I'm trying to get it to work with a multidimensional array. exists and get work. set and unset are giving me a problem though. class ArrayTest implements ArrayAccess { private $_arr = array( 'test' => array( 'bar' => 1, 'baz' => 2 ) ); public function offsetExists($name) { return isset($this->_arr[$name]); } public function offsetSet($name, $value) { $this->_arr[$name] = $value; } public function offsetGet($name) { return $this->_arr[$name]; } public function offsetUnset($name) { unset($this->_arr[$name]); } } $arrTest = new ArrayTest(); isset($arrTest['test']['bar']); // Returns TRUE echo $arrTest['test']['baz']; // Echo's 2 unset($arrTest['test']['bar']; // Error $arrTest['test']['bar'] = 5; // Error I know $_arr could just be made public so you could access it directly, but for my implementation it's not desired and is private. The last 2 lines throw an error: Notice: Indirect modification of overloaded element. I know ArrayAccess just generally doesn't work with multidimensional arrays, but is there anyway around this or any somewhat clean implementation that will allow the desired functionality? The best idea I could come up with is using a character as a separator and testing for it in set and unset and acting accordingly. Though this gets really ugly really fast if you're dealing with a variable depth. Does anyone know why exists and get work so as to maybe copy over the functionality? Thanks for any help anyone can offer.

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