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• Adding up row number and displaying total using COUNT (PHP MySQL)

  - by Yvonne

  I'm attempting to run a query that adds up the total number of subjects in a class. A class has many subjects. There is a 'teachersclasses' table between teachers (the user table) and classes. The principles sounds pretty simple but I'm having some trouble in getting my page to display the number of subjects for each class (directly associated with the teacher) This is what I have so far, trying to make use of the COUNT with a nested SELECT: SELECT (SELECT count(*) FROM subjects WHERE subjects.classid = class.classid) AS total_subjects, class.classname, class.classid FROM class Then I am calling up 'num_subjects' to present the total within a while loop: <?php echo $row['total_subjects']?> From the above, I am receiving the total subjects for a class, but within the same table row (for one class) and my other while loop doesnt run anymore, which returns all of the classes associated with a teacher :( ... Bit of a mess now! I know to return the classes for a particular teacher, I can do an additional WHERE clause on the session of 'teacherid' but I think my query is getting too complicated for me that errors are popping up everywhere. Anyone have a quick fix for this! Thanks very much

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• NSString inheritance

  - by Stef

  Hi, I'm doing an useless thing for my first step in Obj-C @interface String : NSString { int m_isnull; } - (id) init; - (int) isNull; @end @implementation String - (id) init { self = [super init]; m_isnull=1; return self; } - (int) isNull { return m_isnull; } @end test : String *a; a=@"ok"; Works fine, but just 2 little questions 1) When I'm compiling I have this warning warning: incompatible Objective-C types assigning 'struct NSString *', expected 'struct String *' I don't know how to avoid it !? 2) a=@"ok" is a fastest way to initialize a string, but when I'm debugging, I don't stop by at my init constructor why ?

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• How does this module code work?

  - by phsr

  I'm new to ruby and I am trying to figure out how the following code works The following code is inside a class in a module. The method is called later with the following code: @something ||= Module::Class.config class << self def config &block options = OpenStruct.new yield options if block_given? init_client! Client.new(options) end def init_client!(client) base_eigenclass = class << Base; self; end base_eigenclass.send :define_method, :client do @client = client end client end end The class has some constants in it, and when the classes initialize is called, the instance member are set to option.variable || VARIABLE_CONSTANT. I understand that if there is no value for option.variable then VARIABLE_CONSTANT is used, but I don't understand that calling Module::Class.config do |options| #some block end set the @client until config is called again with options The code definitely works, but I want to understand how it does

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• Isses using function with variadic arguments

  - by Sausages

  I'm trying to write a logging function and have tried several different attempts at dealing with the variadic arguments, but am having problems with all of them. Here's the latest: - (void) log:(NSString *)format, ... { if (self.loggingEnabled) { va_list vl; va_start(vl, format); NSString* str = [[NSString alloc] initWithFormat:format arguments:vl]; va_end(vl); NSLog(format); } } If I call this like this: [self log:@"I like: %@", @"sausages"]; Then I get an EXC_BAD_ACCESS at the NSLog line (there's also a compiler warning that the format string is not a string literal). However if in XCode's console I do "po str" it displays "I like: sausages" so str seems ok.

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• In Rails models; for symbols get automatically converted to YAML when saving to DB. What is the corr

  - by Ram

  In my model example Game, has a status column. But I usually set status by using symbols. Example self.status = :active MATCH_STATUS = { :betting_on => "Betting is on", :home_team_won => "Home team has won", :visiting_team_won => "Visiting team has one", :game_tie => "Game is tied" }.freeze def viewable_status MATCH_STATUS[self.status] end I use the above Map to switch between viewable status and viceversa. However when the data gets saved to db, ActiveRecord appends "--- " to each status. So when I retrieve back the status is screwed. What should be the correct approach?

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• HTML5 card game [closed]

  - by ChrisCa

  I created a card game in silverlight a year or so ago in order to learn a bit about Silverlight. I am now wanting to make a HTML5 version of the game in an effort to learn a little bit more about that. I am thinking I'd like to take advantage of stuff like Knockout.js and WebSockets and the canvas element. Now what I'm confused about is how to lay out the cards on the screen. With Silverlight I was able to make a "Hand" control, which was made up of two sub controls - the cards the player has in their hand and the ones they have on the table. And they in turn were made up of Card controls. Now I don't believe there is the concept on a User Control in javascript. So I am possibly thinking about this in entirely the wrong way. So my question is - how could I lay out some cards on the table and perhaps make reuse of something for each player? I have a client side JSON object called game, which contains an array of players. Each player has a hand which is made up of an array of in-hand cards and on-table cards. Ideally I would like to bind these to something using Knockout.js - but I don't know what I could bind to. Would I simply position images (of cards) on a canvas? Is there a way to make some kind of Hand object that each player could have and that I could bind to? Any advice? Or sample code you've seen elsewhere?

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• Passing class method as selector problem.

  - by Anoide

  Hi, I want to build a selector from a class method. I'm doing it this way: NavigationTreeActionHandler* handler=[NavigationTreeActionHandler self]; NavigationTreeNode* bombsNode=new NavigationTreeNode("Bombs","bigbomb.tif" ,handler,@selector(BigBombButtonPressed:)); I need to pass to NavigationTreeNode the target and the selector to the target method. I try to get the target using the self property of the class object (Don't know if htis is the correct way to do it). Then I get the selector for the class method I want to call on the class. Everything compiles ok but it fails when I use: [[handler class] instanceMethodSignatureForSelector:selector]; I get a nil and don't really know why... could anybody help please? Thanks in advance, Olson.

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• getting corresponding value of an attribute from an NSXMLElement

  - by iSight

  Hi, How can i get the corresponding value of an attribute of an NSXMlelement object from a self constructed NSXMLNode.

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• How do I compare 2 fields and return the lowest value of each record?

  - by BigRob

  I'm slowly learning access to make a database of products and suppliers for my parents' business. What i've got is a table of products indexed by our product reference and 2 more tables for 2 different suppliers that contains the suppliers product reference and price that links with our reference. I've made a query that performs a left outer join such that it returns a table of our products with each supplier's reference and price, i.e: Ref | Product Name | Supplier 1 Ref | Supplier 1 Price | Supplier 2 Ref | Supplier 2 Price Here's the query I used: SELECT Catalog.Ref, Catalog.[Product Name], Catalog.Price, [D Products].[Supplier Ref], [D Products].Cost, [GS Products].[Supplier Ref], [GS Products].Cost FROM ([Catalog] LEFT JOIN [D Products] ON Catalog.Ref = [D Products].Ref) LEFT JOIN [GS Products] ON Catalog.Ref = [GS Products].Ref; Not all products are available from both suppliers, hence the outer join. What I want to do (with a query?) is to take the table produced by the query above and simply show the product reference, cheapest supplier reference and cheapest supplier price, i.e: Ref | Cheapest Suppplier Ref | Cheapest Supplier Price Unfortunately my SQL knowledge isn't quite good enough to figure this out, but if anyone can help i'd really appreciate it. Thanks, Rob

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• Serialize object from within

  - by Maximus

  I have the class testClass which has the method save. This method saves object to a database. But it needs to serialize object before saving. How can I serialize object from within the class to do that? class testClass { private $prop = 777; public function save() { $serializedObject = serialize(self); DB::insert('objects', array('id', 'object')) ->values(array(1, $serializedObject)) ->execute(); } } serialize(self) obviously doesn't work.

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• find the difference between two very large list

  - by user157195

  I have two large list(could be a hundred million items), the source of each list can be either from a database table or a flat file. both lists are of comparable sizes, both unsorted. I need to find the difference between them. so I have 3 scenarios: 1. List1 is a database table(assume each row simply have one item(key) that is a string), List2 is a large file. 2. Both lists are from 2 db tables. 3. both lists are from two files. in case 2, I plan to use: select a.item from MyTable a where a.item not in (select b.item form MyTable b) this clearly is inefficient, is there a better way? Another approach is: I plan to sort each list, and then walk down both of them to find the diff. If the list is from a file, I have to read it into a db table first, then use db sorting to output the list. Is the run time complexity still O(nlogn) in db sorting? either approach is a pain and seems would be very slow when the list involved has hundreds of millions of items. any suggestions?

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• Dynamic decision on which class to use

  - by Sirupsen

  Hello, Let's say I have a class named Klass, and a class called Klass2. Depending on the user's input, I'd like to decide whether I'll call "hello_world" on Klass, or Klass2: class Klass def self.hello_world "Hello World from Klass1!" end end class Klass2 def self.hello_world "Hello World from Klass2!" end end input = gets.strip class_to_use = input puts class_to_use.send :hello_world The user inputs "Klass2" and the script should say: Hello World from Klass2! Obviously this code doesn't work, since I'm calling #hello_world on String, but I'd like to call #hello_world on Klass2. How do I "convert" the string into a referrence to Klass2 (or whatever the user might input), or how could I else would I achieve this behavior?

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• Can we use (id) in if- else condition ?

  - by srikanth rongali

  I have written my code in following way in cocos2d. id actionTo = [CCFadeOut actionWithDuration:4.0f]; id actionTo0 = [CCSequence actionWithDuration:2.0f]; if (m < enemyNumber) id actionTo1 = [CCCallFunc actionWithTarget:self selector:@selector(goToNextScene)]; else id actionTo1 = [CCCallFunc actionWithTarget:self selector:@selector(goToEndScene)]; id actionSeq = [CCSequence actions:actionTo, actionTo0, actionTo1, nil]; [targetE runAction: [CCSequence actions:actionSeq, nil]]; error: expected expression before 'id' I am getting the above error. Should not we use (id) in if condition ? I want to get called two selectors by using the if- else condition. How can I make it ? Thank You.

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• ASP.NET MVC: How to show value in a label from selected Drop Down List item?

  - by Lillie

  Hi! I'm trying to show a value of selected Drop Down List item in a label. I managed to make this work with Web Forms but with MVC I'm totally lost. My Index looks like this: [...] <% using (Html.BeginForm()) { %> <table> <tr> <td>Processor</td> <td><%= Html.DropDownList("lstProcessor1", new SelectList((IEnumerable)ViewData["Processor1List"], "product_price", "product_description")) %></td> </tr> <tr> <td>Total Amount</td> <td>0,00 €</td> </tr> </table> <input type="submit" value="Submit" /> <% } %> [...] And my HomeController starts with: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Mvc.Ajax; using MvcApplication1.Models; namespace MvcApplication1.Controllers { [HandleError] public class HomeController : Controller { // Connect database DB50DataContext _ctx = new DB50DataContext(); // GET: /Home/ public ActionResult Index() { // Search: Processors var products = from prod in _ctx.products where prod.product_searchcode == "processor1" select prod; ViewData["Processort1List"] = products; return View(); } I would like the product_price to show on the second line of the table, where it now says 0,00 €. It should also update the price automatically when the item from the Drop Down List is changed. I guess I should use JQuery but I have no idea how. Could someone please give me some tips how to do this?

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• How to deal with delegate method calling back the object who send the message ?

  - by olipion

  I have two object: @protocol ObjectADelegate - (void)objectAfirst:(ObjectA *)obj; - (void)objectAsecond:(ObjectA *)obj; @end @interface ObjectA : NSObject { id<ObjectADelegate> delegate; - (void)callSecond { [self.delegate objectAsecond:self]; } @end @interface ObjectB : NSObject <ObjectADelegate>{ ObjectA *myObjectA; } @implementation ObjectB - (void)objectAfirst:(ObjectA *)obj { // First is finished, do second [obj callSecond]; } - (void)objectASecond:(ObjectA *)obj { // Do my stuff } @end As you can see in the code, when ObjectA send the message objectAfirst to its delegate, objectb use again objectA methods that result in objecta calling back objectb. It means that what first fire objectAfirst is not finished but objectA send the objectAsecond message. Could it be a problem ? Any way to let delay message handling in objectB ? for example, something like using [obj performSelector:@selector(callSecond) afterDelay:0.01]; instead of [obj callSecond]; ?

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• Error reading file with accented vowels

  - by Daniel Dcs

  The following statement to fill a list from a file : action = [] with open (os.getcwd() + "/files/" + "actions.txt") as temp:          action = list (temp) gives me the following error: (result, consumed) = self._buffer_decode (data, self.errors, end) UnicodeDecodeError: 'utf-8' codec can not decode byte 0xf1 in position 67: invalid continuation byte if I add errors = 'ignore': action = [] with open (os.getcwd () + "/ files /" + "actions.txt", errors = 'ignore') as temp:          action = list (temp) Is read the file but not the ñ and vowels accented á-é-í-ó-ú being that python 3 works, as I have understood, default to 'utf-8' I'm looking for a solution for two or more days, and I'm getting more confused. In advance thank you very much for any suggestions.

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• iOS - How to pass information from the VIEW to the Controller?

  - by user1720503

  I am fairly new to programming in general, and have been following the CS193p videos on iTunesU. I am currently doing assignment 3, and am having trouble getting a bit of information from the View sent to the View Controller. I believe I have set up the whole delegation thing correctly, so the question really is to how to get my View Controller to see a bit of information (such as self.bounds.size.width), which is a property that only the View has. Would this involve using self.dataSource? And if so, through what means could I pass this bit of information? Thanks!!

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• How to create arrayType for WSDL in Python (using suds)?

  - by Uri

  Environment: Python v2.6.2 suds v0.3.7 The WSDL (server) I work with, have the following schema sub-sections (I tried to write it clearly using plain text) - [ sub-section #1 ] searchRequest: (searchRequest){ userIdentification = (userIdentification){ username = "" password = "" } itineraryArr = (itineraryArray){ _arrayType = "" _offset = "" _id = "" _href = "" _arrayType = "" } ... ... [ sub-section #2 ] itinerary: (itinerary){ departurePoint = (locationPoint){ locationId = None radius = None } arrivalPoint = (locationPoint){ locationId = None radius = None } ... ... There is no problem with 'userIdentification' (which is a "simple" type) But, 'itineraryArr' is an array of 'itinerary', and I don't know how to use python to create XML array. I tried few combinations, for example itinerary0 = self.client.factory.create('itinerary') itineraryArray = self.client.factory.create('itineraryArray') itineraryArray = [itinerary0] searchRequest.itineraryArr = itineraryArray But all my trials resulted with the same server error - Server raised fault: 'Cannot use object of type itinerary as array' (Fault){ faultcode = "SOAP-ENV:Server" faultstring = "Cannot use object of type itinerary as array" } Appreciate you help..... Thanks, Uri

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• adding button to the navigation bar

  - by praseed

  hi friends, i have a problem while adding button to the navigation bar.. My application consist of two view controllers added to the viewControllers array of a tabBarController. Inturn this tabBarController is added to the viewControllers array of a navigationController. In one of the views i have a textfield for entering dates . On the tap of this textfield the datepicker will pop up. simultaneously i want to display a done button on the navigation bar. how can i do this... i tried using self.tabBarController.navigationController.navigationItem.rightBarButtonItem = self.doneButton; But this is not working... Pls help me out..

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• How to release my view from stack ?

  - by aman-gupta

  Hi, In my application I m using following coding convention to open my default screen :-- AppDelegate *ptrDefaultScreen = (AppDelegate *)[[UIApplication sharedApplication]delegate]; [self.navigationController presentModalViewController:ptrDefaultScreen.FrmFlashScreenLink animated:YES]; but when I move to other screen after default screen ,my default screen is still exists even i used [self dismissModelViewController:YES]; to dimiss default screen from view. where I m wrong I want my default screen will be completely removed from view. Is any other way to call default screen before actual application. Please help me out.Thanks in advance

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• mysql report sql help

  - by sfgroups

  I have mysql table with data like this. record will have server with total cpu and virtual server with cpu assinged type, cpu srv1, 10 vsrv11, 2 vsrv12, 3 srv2, 15 vsrv21, 6 vsrv22, 7 vsrv23, 1 from the above data, I want to create output like this. server, total cpu, assigned cpu, free cpu srv1, 10, 5, 5 srv2, 15, 14, 1 Can you help me on creating sql query for this report? I have changed my table and data like this. CREATE TABLE `cpuallocation` ( `servertype` varchar(10) DEFAULT NULL, `servername` varchar(20) DEFAULT NULL, `hostname` varchar(20) DEFAULT NULL, `cpu_count` float DEFAULT NULL, UNIQUE KEY `server_uniq_idx` (`servertype`,`servername`,`hostname`) insert into cpuallocation values('srv', 'server1', '',16); insert into cpuallocation values('vir', 'server1', 'host1',5); insert into cpuallocation values('vir', 'server1', 'host2',2.5); insert into cpuallocation values('vir', 'server1', 'host3',4.5); insert into cpuallocation values('srv', 'server2', '',8); insert into cpuallocation values('vir', 'server2', 'host1',5); insert into cpuallocation values('vir', 'server2', 'host2',2.5); insert into cpuallocation values('srv', 'server3', '',24); insert into cpuallocation values('vir', 'server3', 'host1',12); insert into cpuallocation values('vir', 'server3', 'host2',2); insert into cpuallocation values('srv', 'server4', '',12); Update: I created two view, now I getting the result I want. create view v1 as select servername, sum(cpu_count) as cpu_allocated from cpuallocation where servertype='vir' group by servername; create view v2 as select servername, cpu_count as total_cpu from cpuallocation where servertype='srv'; select a.servername, a.total_cpu, b.cpu_allocated from v2 as a left join v1 as b on a.servername=b.servername; +------------+-----------+---------------+ | servername | total_cpu | cpu_allocated | +------------+-----------+---------------+ | server1 | 16 | 12 | | server2 | 8 | 7.5 | | server3 | 24 | 14 | | server4 | 12 | NULL | +------------+-----------+---------------+ 4 rows in set (0.00 sec) Is it possible to create a query with-out creating views?

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• Using ddply() to Get Frequency of Certain IDs, by Appearance in Multiple Rows (in R)

  - by EconomiCurtis

  Goal If the following description is hard follow, please see the example "before" and "after" to see a straightforward example. I have bartering data, with unique trade ids, and two sides of the trade. Side1 and Side2 are baskets, lists of item ids that represent both sides of the barter transaction. I'd like to count the frequency each ITEM appears in TRADES. E.g, if item "001" appeared in 3 trades, I'd have a count of 3 (ignoring how many times the item appeared in each trade). Further, I'd like to do this with the plyr ddply function. (If you're interested as to my motivation, I working over many hundreds of thousands of transactions and am already using a ddply to calculate several other summary statistics. I'd like to add this to the ddply I'm already using, rather than calculate it after, and merge it into the ddply output.... sorry if that was difficult to follow.) In terms of pseudo code I'm working off of: merge each row of Side1 and Side2 by row, get unique() appearances of each item id apply table() function transpose and relabel output from table Example of the structure of my data, and the output I desire. Data Example (before): df <- data.frame(TradeID = c("01","02","03","04")) df$Side1 = list(c("001","001","002"), c("002","002","003"), c("001","004"), c("001","002","003","004")) df$Side2 = list(c("001"),c("007"),c("009"),c()) Desired Output (after): df.ItemRelFreq_byTradeID <- data.frame(ItemID = c("001","002","003","004","007","009"), RelFreq_byTrade = c(3,3,2,2,1,1)) One method to do this without ddply I've worked out one way to do this below. My problem is that I can't quite seem to get ddply to do this for me. temp <- table(unlist(sapply(mapply(c,df$Side1,df$Side2), unique))) df.ItemRelFreq_byTradeID <- data.frame(ItemID = names(temp), RelFreq_byTrade = temp[]) Thanks for any help you can offer! Curtis

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• VS2005: two projects doing identical tasks but with different result

  - by Craig Johnston

  In VS2005 I have multi-project solution. Two of the projects use an external set of DLLs to create a report, using report definition data taken from an SQL Server. One of the projects creates the report just fine, but the other project results in an Exception. I have checked that the projects are referencing the same versions of the all the DLLs and they appear to be identical. What could the cause of this problem?

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• hash tables and 2d vectors

  - by Sunil

  I want to push a 2d vector into a hash table row by row and later search for a row (vector) in the hash table and want to be able to find it. I want to do something like #include <iostream> #include <set> #include <vector> using namespace std; int main(){ std::set < vector<int> > myset; vector< vector<int> > v; int k = 0; for ( int i = 0; i < 5; i++ ) { v.push_back ( vector<int>() ); for ( int j = 0; j < 5; j++ ) v[i].push_back ( k++ ); } for ( int i = 0; i < 5; i++ ) { std::copy(v[i].begin(),v[i].end(),std::inserter(myset)); // This is not correct but what is the right way ? // and also here, I want to search for a particular vector if it exists in the table. for ex. the second row of vector v. } return 0; } I'm not sure how to insert and look up a vector in a set. So if nybody could guide me, it will be helpful. Thanks

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• Strange PHP array behavior overwriting values with all the same values

  - by dasdas

  Im doing a simple mysqli query with code ive used many times before but have never had this problem happen to me. I am grabbing an entire table with an unknown number of columns (it changes often so i dont know the exact value, nor the column names). I have some code that uses metadata to grab everything and stick it in an array. This all works fine, but the output is messed up: $stmt -> execute(); //the query is legit, no problems there $meta = $stmt->result_metadata(); while ($field = $meta->fetch_field()) { $params[] = &$row[$field->name]; } call_user_func_array(array($stmt, 'bind_result'), $params); while ($stmt->fetch()) { $pvalues[++$i] = $row; //$pvalues is an array of arrays. row is an array //print_r($row); print_r($pvalues[$i-1]); } $stmt -> close(); I would assume that $pvalues has the results that I am looking for. My table currently has 2 rows. $pvalues has array length 2. Both rows in $pvalues are exactly the same. If i use the: print_r($row) it prints out the correct values for both rows, but if later on i check what is in $pvalues it is incorrect (1 row is assigned to both indices of $pvalues). If i use the print_r($pvalues[$i-1]) it prints exactly as I expect, the same row in the table twice. Why isnt the data getting assigned to $pvalues? I know $row holds the right information at one point, but it is getting overwritten or lost.

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