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  • AJAX Autocomplete appears at a random vertical position, not touching the textbox

    - by Tim
    Hi, I am using the AJAX Autocomplete extender for ASP.NET 2. Everything works fine...I am calling a webservice which gets me the values to fill the drop down with after 3 letters are typed into certain es. I have set the maxheight attribute and am using a scrollbar in case there are more entries than would fit that height. However, I notice that in some cases, the drop down appears at a random position on the screen, i.e. rather than connected to the relevant textbox, sometimes it appears with its entries above the textbox, not touching it at all. Sometimes it would have just one entry and it would appear in the middle of the screen vertically above the textbox it is associated to. Is there a reason why this is happening?

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  • Random Record from Recordset

    - by Tony Hanks
    I have the fillowing Query: SELECT a.*, ps4_media.filename, ps4_galleries.name as galleryname, ps4_media_iptc.description, ps4_media_iptc.title, ps4_media_iptc.headline, ps4_media.date_added, ps4_galleries.created, ps4_folders.name as foldername, ps4_galleries.gallery_count FROM ps4_media_galleries a INNER JOIN (SELECT ps4_media_galleries.gallery_id, min(ps4_media_galleries.gmedia_id) AS minID FROM ps4_media_galleries GROUP BY ps4_media_galleries.gallery_id) b ON a.gallery_id = b.gallery_id AND a.gmedia_id = b.minID INNER JOIN ps4_media ON ps4_media.media_id = a.gmedia_id INNER JOIN ps4_folders ON ps4_folders.folder_id = ps4_media.folder_id INNER JOIN ps4_galleries ON ps4_galleries.gallery_id = a.gallery_id INNER JOIN ps4_media_iptc ON ps4_media_iptc.media_id = a.gmedia_id ORDER BY ps4_galleries.created DESC How do I get ps4_media.filename to be random, everything else is fine just want the thumbnail which ps4_media.filename is to be and of the records in the found set.

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  • PHP - displaying 1 random record for each week

    - by mike
    I want to display 1 random record from a database based on the week. I need to determine if it's a new, and if it is a new week, then select the record and display the new record. I'm thinking I can just use a single day of the week to generate the new record, either way will work. I'm really having a hard time conceptualizing how I'll store the record id and not select a new one when someone visits again the same day or refreshes the page. Any ideas? Let me know if I wasn't clear enough.

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  • Random password variable disappears

    - by snaken
    Hi, I'm using the following to generate a random password in a shell script: DBPASS=</dev/urandom tr -dc A-Za-z0-9| (head -c $1 > /dev/null 2>&1 || head -c 8) When i run this in a file on its own like this: #!/bin/sh DBPASS=</dev/urandom tr -dc A-Za-z0-9| (head -c $1 > /dev/null 2>&1 || head -c 8) echo $DBPASS A password is echoed. When i incorporate it into a larger script though the variable never seems to get created for some reason, so for example this doesn't work: DBPASS=</dev/urandom tr -dc A-Za-z0-9| (head -c $1 > /dev/null 2>&1 || head -c 8) sed -i s/oldpass/$DBPASS/ mysql_connect.php If i manually set the variable though everything is fine.. can anyone see why?

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  • Is generating real random numbers this easy in C#?

    - by JL
    I found this code using Google. private int RandomNumber(int min, int max) { Random random = new Random(); return random.Next(min, max); } Is this really all there is to generating REAL random numbers in C#? I intend to generate on a small scale between values 1-10. Thanks

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  • phonegap.js crashes android app

    - by peirix
    I'm having this weird problem, where including the phonegap.js file in my project causes the app to crash on both the android emulator and my phone. I got the latest file from GitHub, so I can't see why this isn't working. This happens even if I try to build the sample project that's included in the PhoneGap download... Console log: [2010-12-17 11:05:14 - sample] Android Launch! [2010-12-17 11:05:14 - sample] adb is running normally. [2010-12-17 11:05:14 - sample] Performing com.phonegap.sample.sample activity launch [2010-12-17 11:05:14 - sample] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'FirstDevice' [2010-12-17 11:05:16 - sample] Uploading sample.apk onto device 'emulator-5554' [2010-12-17 11:05:16 - sample] Installing sample.apk... [2010-12-17 11:05:21 - sample] Success! [2010-12-17 11:05:22 - sample] Starting activity com.phonegap.sample.sample on device emulator-5554 [2010-12-17 11:05:23 - sample] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.phonegap.sample/.sample } LogCat: 12-17 11:13:12.533: DEBUG/AndroidRuntime(373): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<< 12-17 11:13:12.533: DEBUG/AndroidRuntime(373): CheckJNI is ON 12-17 11:13:13.453: DEBUG/AndroidRuntime(373): Calling main entry com.android.commands.pm.Pm 12-17 11:13:13.503: DEBUG/AndroidRuntime(373): Shutting down VM 12-17 11:13:13.513: DEBUG/dalvikvm(373): GC_CONCURRENT freed 101K, 71% free 297K/1024K, external 0K/0K, paused 2ms+2ms 12-17 11:13:13.523: INFO/AndroidRuntime(373): NOTE: attach of thread 'Binder Thread #3' failed 12-17 11:13:13.523: DEBUG/dalvikvm(373): Debugger has detached; object registry had 1 entries 12-17 11:13:14.113: DEBUG/AndroidRuntime(383): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<< 12-17 11:13:14.113: DEBUG/AndroidRuntime(383): CheckJNI is ON 12-17 11:13:14.853: DEBUG/AndroidRuntime(383): Calling main entry com.android.commands.am.Am 12-17 11:13:14.894: INFO/ActivityManager(62): Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.phonegap.sample/.sample } from pid 383 12-17 11:13:14.973: INFO/ActivityManager(62): Start proc com.phonegap.sample for activity com.phonegap.sample/.sample: pid=391 uid=10031 gids={1006, 3003, 1015} 12-17 11:13:14.983: DEBUG/AndroidRuntime(383): Shutting down VM 12-17 11:13:15.053: DEBUG/dalvikvm(383): GC_CONCURRENT freed 102K, 69% free 319K/1024K, external 0K/0K, paused 2ms+2ms 12-17 11:13:15.093: INFO/AndroidRuntime(383): NOTE: attach of thread 'Binder Thread #3' failed 12-17 11:13:15.143: DEBUG/dalvikvm(383): Debugger has detached; object registry had 1 entries 12-17 11:13:15.523: DEBUG/dalvikvm(33): GC_EXPLICIT freed 11K, 54% free 2520K/5379K, external 716K/1038K, paused 467ms 12-17 11:13:15.663: DEBUG/dalvikvm(33): GC_EXPLICIT freed <1K, 54% free 2520K/5379K, external 716K/1038K, paused 132ms 12-17 11:13:15.772: DEBUG/dalvikvm(33): GC_EXPLICIT freed <1K, 54% free 2520K/5379K, external 716K/1038K, paused 113ms 12-17 11:13:16.333: INFO/ARMAssembler(62): generated scanline__00000177:03515104_00001002_00000000 [ 87 ipp] (110 ins) at [0x43aff6f0:0x43aff8a8] in 686000 ns 12-17 11:13:17.493: INFO/ActivityManager(62): Displayed com.phonegap.sample/.sample: +2s540ms 12-17 11:13:18.163: DEBUG/szipinf(391): Initializing inflate state 12-17 11:13:18.173: DEBUG/szipinf(391): Initializing zlib to inflate 12-17 11:13:18.573: WARN/dalvikvm(391): JNI WARNING: jarray 0x40567330 points to non-array object (Ljava/lang/String;) 12-17 11:13:18.593: INFO/dalvikvm(391): "WebViewCoreThread" prio=5 tid=9 NATIVE 12-17 11:13:18.603: INFO/dalvikvm(391): | group="main" sCount=0 dsCount=0 obj=0x4051b880 self=0x1af760 12-17 11:13:18.603: INFO/dalvikvm(391): | sysTid=400 nice=0 sched=0/0 cgrp=default handle=1778000 12-17 11:13:18.623: INFO/dalvikvm(391): | schedstat=( 851184092 892639082 140 ) 12-17 11:13:18.633: INFO/dalvikvm(391): at android.webkit.LoadListener.nativeFinished(Native Method) 12-17 11:13:18.633: INFO/dalvikvm(391): at android.webkit.LoadListener.nativeFinished(Native Method) 12-17 11:13:18.653: INFO/dalvikvm(391): at android.webkit.LoadListener.tearDown(LoadListener.java:1200) 12-17 11:13:18.653: INFO/dalvikvm(391): at android.webkit.LoadListener.handleEndData(LoadListener.java:721) 12-17 11:13:18.653: INFO/dalvikvm(391): at android.webkit.LoadListener.handleMessage(LoadListener.java:219) 12-17 11:13:18.672: INFO/dalvikvm(391): at android.os.Handler.dispatchMessage(Handler.java:99) 12-17 11:13:18.672: INFO/dalvikvm(391): at android.os.Looper.loop(Looper.java:123) 12-17 11:13:18.672: INFO/dalvikvm(391): at android.webkit.WebViewCore$WebCoreThread.run(WebViewCore.java:629) 12-17 11:13:18.672: INFO/dalvikvm(391): at java.lang.Thread.run(Thread.java:1019) 12-17 11:13:18.672: ERROR/dalvikvm(391): VM aborting 12-17 11:13:18.887: INFO/DEBUG(31): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** 12-17 11:13:18.887: INFO/DEBUG(31): Build fingerprint: 'generic/sdk/generic:2.3/GRH55/79397:eng/test-keys' 12-17 11:13:18.893: INFO/DEBUG(31): pid: 391, tid: 400 >>> com.phonegap.sample <<< 12-17 11:13:18.893: INFO/DEBUG(31): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr deadd00d 12-17 11:13:18.893: INFO/DEBUG(31): r0 fffffebc r1 deadd00d r2 00000026 r3 00000000 12-17 11:13:18.893: INFO/DEBUG(31): r4 81da45c8 r5 40567330 r6 81d8592c r7 001b2a48 12-17 11:13:18.893: INFO/DEBUG(31): r8 43640b58 r9 42dd1ecc 10 42dd1eb4 fp 4168d82c 12-17 11:13:18.893: INFO/DEBUG(31): ip 81da4728 sp 43640410 lr afd19375 pc 81d45a02 cpsr 20000030 12-17 11:13:19.183: INFO/DEBUG(31): #00 pc 00045a02 /system/lib/libdvm.so 12-17 11:13:19.183: INFO/DEBUG(31): #01 pc 000376fc /system/lib/libdvm.so 12-17 11:13:19.183: INFO/DEBUG(31): #02 pc 000399c4 /system/lib/libdvm.so 12-17 11:13:19.193: INFO/DEBUG(31): #03 pc 0003a4a0 /system/lib/libdvm.so 12-17 11:13:19.203: INFO/DEBUG(31): #04 pc 0032b6d6 /system/lib/libwebcore.so 12-17 11:13:19.203: INFO/DEBUG(31): #05 pc 002a4da4 /system/lib/libwebcore.so 12-17 11:13:19.203: INFO/DEBUG(31): #06 pc 001a6136 /system/lib/libwebcore.so 12-17 11:13:19.213: INFO/DEBUG(31): #07 pc 002a5870 /system/lib/libwebcore.so 12-17 11:13:19.223: INFO/DEBUG(31): #08 pc 00359e36 /system/lib/libwebcore.so 12-17 11:13:19.223: INFO/DEBUG(31): #09 pc 0035d30e /system/lib/libwebcore.so 12-17 11:13:19.223: INFO/DEBUG(31): #10 pc 003638be /system/lib/libwebcore.so 12-17 11:13:19.233: INFO/DEBUG(31): #11 pc 0019f6fa /system/lib/libwebcore.so 12-17 11:13:19.233: INFO/DEBUG(31): #12 pc 0019f780 /system/lib/libwebcore.so 12-17 11:13:19.243: INFO/DEBUG(31): #13 pc 001a3d8a /system/lib/libwebcore.so 12-17 11:13:19.243: INFO/DEBUG(31): #14 pc 000d0dca /system/lib/libwebcore.so 12-17 11:13:19.253: INFO/DEBUG(31): #15 pc 000d0f28 /system/lib/libwebcore.so 12-17 11:13:19.253: INFO/DEBUG(31): #16 pc 000d106e /system/lib/libwebcore.so 12-17 11:13:19.253: INFO/DEBUG(31): #17 pc 000ddef0 /system/lib/libwebcore.so 12-17 11:13:19.263: INFO/DEBUG(31): #18 pc 000ddf62 /system/lib/libwebcore.so 12-17 11:13:19.263: INFO/DEBUG(31): #19 pc 000f3ce2 /system/lib/libwebcore.so 12-17 11:13:19.273: INFO/DEBUG(31): #20 pc 002739ae /system/lib/libwebcore.so 12-17 11:13:19.273: INFO/DEBUG(31): #21 pc 000eac5e /system/lib/libwebcore.so 12-17 11:13:19.273: INFO/DEBUG(31): #22 pc 001b152c /system/lib/libwebcore.so 12-17 11:13:19.283: INFO/DEBUG(31): #23 pc 00017d34 /system/lib/libdvm.so 12-17 11:13:19.283: INFO/DEBUG(31): #24 pc 00048ec0 /system/lib/libdvm.so 12-17 11:13:19.283: INFO/DEBUG(31): #25 pc 00041a6a /system/lib/libdvm.so 12-17 11:13:19.293: INFO/DEBUG(31): #26 pc 0001cf94 /system/lib/libdvm.so 12-17 11:13:19.303: INFO/DEBUG(31): #27 pc 0002209c /system/lib/libdvm.so 12-17 11:13:19.303: INFO/DEBUG(31): #28 pc 00020f90 /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): #29 pc 0005f328 /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): #30 pc 0005f54e /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): #31 pc 00053b06 /system/lib/libdvm.so 12-17 11:13:19.313: INFO/DEBUG(31): code around pc: 12-17 11:13:19.313: INFO/DEBUG(31): 81d459e0 447a4479 ed0cf7d1 20004c09 ee34f7d1 12-17 11:13:19.323: INFO/DEBUG(31): 81d459f0 447c4808 6bdb5823 d0002b00 49064798 12-17 11:13:19.323: INFO/DEBUG(31): 81d45a00 700a2226 eea0f7d1 0004355f 0004511d 12-17 11:13:19.323: INFO/DEBUG(31): 81d45a10 0005ebd2 fffffebc deadd00d b510b40e 12-17 11:13:19.323: INFO/DEBUG(31): 81d45a20 4c0a4b09 447bb083 aa05591b 6b5bca02 12-17 11:13:19.323: INFO/DEBUG(31): code around lr: 12-17 11:13:19.333: INFO/DEBUG(31): afd19354 b0834a0d 589c447b 26009001 686768a5 12-17 11:13:19.333: INFO/DEBUG(31): afd19364 220ce008 2b005eab 1c28d003 47889901 12-17 11:13:19.333: INFO/DEBUG(31): afd19374 35544306 d5f43f01 2c006824 b003d1ee 12-17 11:13:19.333: INFO/DEBUG(31): afd19384 bdf01c30 000281a8 ffffff88 1c0fb5f0 12-17 11:13:19.333: INFO/DEBUG(31): afd19394 43551c3d a904b087 1c16ac01 604d9004 12-17 11:13:19.333: INFO/DEBUG(31): stack: 12-17 11:13:19.333: INFO/DEBUG(31): 436403d0 00000015 12-17 11:13:19.333: INFO/DEBUG(31): 436403d4 afd18407 /system/lib/libc.so 12-17 11:13:19.333: INFO/DEBUG(31): 436403d8 afd4270c /system/lib/libc.so 12-17 11:13:19.343: INFO/DEBUG(31): 436403dc afd426b8 /system/lib/libc.so 12-17 11:13:19.343: INFO/DEBUG(31): 436403e0 00000000 12-17 11:13:19.343: INFO/DEBUG(31): 436403e4 afd19375 /system/lib/libc.so 12-17 11:13:19.353: INFO/DEBUG(31): 436403e8 001af760 [heap] 12-17 11:13:19.353: INFO/DEBUG(31): 436403ec afd183d9 /system/lib/libc.so 12-17 11:13:19.353: INFO/DEBUG(31): 436403f0 001b2a48 [heap] 12-17 11:13:19.353: INFO/DEBUG(31): 436403f4 0005ebd2 [heap] 12-17 11:13:19.353: INFO/DEBUG(31): 436403f8 40567330 /dev/ashmem/dalvik-heap (deleted) 12-17 11:13:19.363: INFO/DEBUG(31): 436403fc 81d8592c /system/lib/libdvm.so 12-17 11:13:19.363: INFO/DEBUG(31): 43640400 001b2a48 [heap] 12-17 11:13:19.363: INFO/DEBUG(31): 43640404 afd18437 /system/lib/libc.so 12-17 11:13:19.363: INFO/DEBUG(31): 43640408 df002777 12-17 11:13:19.363: INFO/DEBUG(31): 4364040c e3a070ad 12-17 11:13:19.363: INFO/DEBUG(31): #00 43640410 00000001 12-17 11:13:19.363: INFO/DEBUG(31): 43640414 81d37701 /system/lib/libdvm.so 12-17 11:13:19.363: INFO/DEBUG(31): #01 43640418 00000001 12-17 11:13:19.363: INFO/DEBUG(31): 4364041c 81d399c9 /system/lib/libdvm.so 12-17 11:13:22.753: INFO/BootReceiver(62): Copying /data/tombstones/tombstone_09 to DropBox (SYSTEM_TOMBSTONE) 12-17 11:13:22.943: DEBUG/dalvikvm(62): GC_CONCURRENT freed 876K, 48% free 4240K/8135K, external 2269K/3469K, paused 9ms+10ms 12-17 11:13:23.133: DEBUG/dalvikvm(62): GC_FOR_MALLOC freed 348K, 47% free 4318K/8135K, external 2269K/3469K, paused 147ms 12-17 11:13:23.243: DEBUG/Zygote(33): Process 391 terminated by signal (11) 12-17 11:13:23.253: ERROR/InputDispatcher(62): channel '406defc8 com.phonegap.sample/com.phonegap.sample.sample (server)' ~ Consumer closed input channel or an error occurred. events=0x8 12-17 11:13:23.253: ERROR/InputDispatcher(62): channel '406defc8 com.phonegap.sample/com.phonegap.sample.sample (server)' ~ Channel is unrecoverably broken and will be disposed! 12-17 11:13:23.323: DEBUG/dalvikvm(62): GC_FOR_MALLOC freed 134K, 47% free 4376K/8135K, external 2269K/3469K, paused 174ms 12-17 11:13:23.323: INFO/ActivityManager(62): Process com.phonegap.sample (pid 391) has died. 12-17 11:13:23.333: INFO/WindowManager(62): WIN DEATH: Window{406defc8 com.phonegap.sample/com.phonegap.sample.sample paused=false} 12-17 11:13:23.542: DEBUG/dalvikvm(124): GC_EXPLICIT freed 61K, 51% free 2836K/5767K, external 1973K/2288K, paused 907ms 12-17 11:13:23.693: WARN/InputManagerService(62): Got RemoteException sending setActive(false) notification to pid 391 uid 10031 Sorry about the gigantic log posts, but I don't know what is of importance here...

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  • Caliburn and prism samples

    - by Simon
    Are there any sample applications avaliable that make use of both caliburn and prism? I know there are blogs that talk about it but I would like to wade into some code and see how it all fits together. http://caliburn.codeplex.com http://compositewpf.codeplex.com/

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  • python multithreading for dummies

    - by albruno
    trying to find a simple example that clearly shows a single task being divided for multi-threading. Quite frankly... many of the examples are overly sophisticated thus.... making the flow tougher to play with... anyone care to share their breakthrough sample or point to an example? As well, what is the best docs? many google lookups are too specific (for me at this stage) Thanks in advance.

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  • Generating unique N-valued key

    - by Bar
    Hi, StackOverflow! I want to generate unique random, N-valued key. This key can contain numbers and latin characters, i.e. A-Za-z0-9. The only solution I am thinking about is something like this (pseudocode): key = ""; smb = "ABC…abc…0123456789"; // allowed symbols for (i = 0; i < N; i++) { key += smb[rnd(0, smb.length() - 1)]; // select symbol at random position } Is there any better solution? What can you suggest? TIA, Michael.

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  • Order By Rand by Time (HQL)

    - by Felipe
    Hi all, I'm developing a web application using asp.net Mvc 2 and NHibernate, and I'm paging data (products in a category) in my page, but this data are random, so, I'm using a HQL statement link this: string hql = "from Product p where p.Category.Id=:IdCategory order by rand()"; It's working fine, but when I page, sometimes the same product appears in the first, second, etc... pages because it's order by rand(). Is there any way to make a random order by fixed by period (time internal) ? Or any solution ? thanks Cheers

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  • Linq to NHibernate, Order by Rand() ?

    - by Felipe
    Hi everybody, I'm using Linq To Nhibernate, and with a HQL statement I can do something like this: string hql = "from Entity e order by rand()"; Andi t will be ordered so random, and I'd link to know How can I do the same statement with Linq to Nhibernate ? I try this: var result = from e in Session.Linq<Entity> orderby new Random().Next(0,100) select e; but it throws a exception and doesn't work... is there any other way or solution? Thanks Cheers

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  • How to increment counters based on a printed array

    - by Sam Liew
    I managed to developed a simple board of 5x5 using random numbers and array. Big achievement for someone like me! :) Now I have to increment the counters depending on the frequency of the numbers. If the value within 0-49 is printed..then nCounter++ If the value within 50-75 is printed..then pCounter++ something like that. The problem is that I don't know how to increase the counters based on the printed board. Here is the code: #include <stdio.h> #include <stdlib.h> #include <time.h> int main() { //Initialize Variables int randomNumber; int rows; int columns; int hdCounter =0; int hCounter = 0; int cCounter = 0; int pCounter = 0; int nCounter = 0; //Declare board size int board[5][5]; //size of board is 5 x 5 //Create the random number generator seed srand(time(NULL)); //Assign the random numbers from 1 - 25 into variable randomNumber //Create the rows for the board for ( rows = 1; rows <= 5 ; rows++ ) { //Create the colimns for the board for ( columns = 1; columns <= 5 ; columns++ ) { //Assign variable randomNumber into variable board randomNumber = rand() %100 + 1; board[rows][columns] = randomNumber; //print the board printf("%d\t", board[rows][columns]); //calculate the frequency of numbers on the printed board if (randomNumber >= 85 && randomNumber <= 100 ) hdCounter++; else if ( randomNumber >= 75 ) hCounter++; else if ( randomNumber >= 65 ) cCounter++; else if ( randomNumber >= 50 ) pCounter++; else if ( randomNumber >= 1 ) nCounter++; else continue; } //Newline after the end of 5th column. printf("\n\n"); } printf( "N \t P \t C \t H \t HD\n\n" ); printf("%d \t %d \t %d \t %d \t %d \t", nCounter, pCounter, cCounter, hCounter, hdCounter); }//end main I tried replacing randomNumber in the if-statement with board[rows][columns] but I seem to get the same undesired results.

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  • How to get unique numbers using randomint python?

    - by user2519572
    I am creating a 'Euromillions Lottery generator' just for fun and I keep getting the same numbers printing out. How can I make it so that I get random numbers and never get the same number popping up: from random import randint numbers = randint(1,50) stars = randint(1,11) print "Your lucky numbers are: ", numbers, numbers, numbers, numbers, numbers print "Your lucky stars are: " , stars, stars The output is just: >>> Your lucky numbers are: 41 41 41 41 41 >>> Your lucky stars are: 8 8 >>> Good bye! How can I fix this? Regards

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  • Characteristics of an Initialization Vector

    - by Jamie Chapman
    I'm by no means a cryptography expert, I have been reading a few questions around Stack Overflow and on Wikipedia but nothing is really 'clear cut' in terms of defining an IV and it's usage. Points I have discovered: An IV is pre-pended to a plaintext message in order to strengthen the encryption The IV is truely random Each message has it's own unique IV Timestamps and cryptographic hashes are sometimes used instead of random values, but these are considered to be insecure as timestamps can be predicted One of the weaknesses of WEP (in 802.11) is the fact that the IV will reset after a specific amount of encryptions, thus repeating the IV I'm sure there are many other points to be made, what have I missed? (or misread!)

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  • Choose item from a list with bias?

    - by ooboo
    Given a list of items x1 ... xn and associated probabilties p1 ... pn that sum up to 1 there's a well known procedure to select a random item with its associated proabability by sorting the list according to weight, choosing a random value between 1 and 0, and adding up to a culmination sum until it exceeds the value selected and return the item at this point. So if we have x1 - 0.5, x2 - 0.3, x3 - 0.2, if the randomly chosen value is less than 0.5 x1 will be chosen, if between 0.5 and 0.8, x2, and else x3. This requires sorting so it needs O(nlogn) time. Is there anything more efficient than that?

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  • How are a session identifiers generated?

    - by Asaf R
    Most web applications depend on some kind of session with the user (for instance, to retain login status). The session id is kept as a cookie in the user's browser and sent with every request. To make it hard to guess the next user's session these session-ids need to be sparse and somewhat random. The also have to be unique. The question is - how to efficiently generate session ids that are sparse and unique? This question has a good answer for unique random numbers, but it seems not scalable for a large range of numbers, simply because the array will end up taking a lot of memory.

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  • Mean of Sampleset and powered Sampleset

    - by Milla Well
    I am working on an ICA implementation wich is based on the assumption, that all source signals are independent. So I checked on the basic concepts of Dependence vs. Correlation and tried to show this example on sample data from numpy import * from numpy.random import * k = 1000 s = 10000 mn = 0 mnPow = 0 for i in arange(1,k): a = randn(s) a = a-mean(a) mn = mn + mean(a) mnPow = mnPow + mean(a**3) print "Mean X: ", mn/k print "Mean X^3: ", mnPow/k But I couldn't produce the last step of this example E(X^3) = 0: >> Mean X: -1.11174580826e-18 >> Mean X^3: -0.00125229267144 First value I would consider to be zero, but second value is too large, isn't it? Since I subtract the mean of a, I expected the mean of a^3 to be zero as well. Does the problem lie in the random number generator, the precision of the numerical values in my misunderstanding of the concepts of mean and expected value?

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  • How to get some randomized concats based on 2 columns from 1 table?

    - by Nils Riedemann
    Hey folks, i have a large user Database (13k+), and for some reason i need to create random names. The users table has "first_name" and "last_name". Now i want to have 10 concats of full_name and last_name of two completely random rows. Is that even possible with SQL? My other idea was just to create a full_names and last_names table … but that would'nt be as much challenging. Oh, and it should not take up too much performance :) (so order by rand() is not an option ;))

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  • How many double numbers are there between 0.0 and 1.0?

    - by polygenelubricants
    This is something that's been on my mind for years, but I never took the time to ask before. Many (pseudo) random number generators generate a random number between 0.0 and 1.0. Mathematically there are infinite numbers in this range, but double is a floating point number, and therefore has a finite precision. So the questions are: Just how many double numbers are there between 0.0 and 1.0? Are there just as many numbers between 1 and 2? Between 100 and 101? Between 10^100 and 10^100+1? Note: if it makes a difference, I'm interested in Java's definition of double in particular.

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  • C++ function for picking from a list where each element has a distinct probability

    - by Stuart
    I have an array of structs and one of the fields in the struct is a float. I want to pick one of the structs where the probability of picking it is relative to the value of the float. ie struct s{ float probability; ... } sArray s[50]; What is the fastest way to decide which s to pick? Is there a function for this? If I knew the sum of all the probability fields (Note it will not be 1), then could I iterate through each s and compare probability/total_probability with a random number, changing the random number for each s? ie if( (float) (rand() / RAND_MAX) < probability)...

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