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• Solving problems with near infinite potential solutions

  - by Zonda333

  Today I read the following problem: Use the digits 2, 0, 1, 1 and the operations +, -, x, ÷, sqrt, ^ , !, (), combinations, and permutations to write equations for the counting numbers 1 through 100. All four digits must be used in each expression. Only the digits 2, 0, 1, 1 may be used, and each must be used exactly once. Decimals may be used, as in .1, .02, etc. Digits may be combined; numbers such as 20 or 101 may be used. Example: 60 = 10*(2+1)!, 54 = ¹¹C2 - 0! Though I was able to quickly find around 50 solutions quite easily in my head, I thought programming it would be a far superior solution. However, I then realized I had no clue how to go about solving a problem like this. I am not asking for complete code for me to copy and paste, but for ideas about how I would solve this problems, and others like it that have nearly infinite potential solutions. As I will be writing it in python, where I have the most experience, I would prefer if the answers were more python based, but general ideas are great too.

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• Unable to Connect to Management Studio Server

  - by Phil Hilliard

  I have a nasty situation. I am using Microsoft SQL Server Management Studio Express edition locally on my pc for testing, and once tested I upload database changes to a remote server. I have a situation where I deleted the Default Database on my local machine, and instead of searching hard enough to find an answer to that problem, I uninstalled and reinstalled Management Studio. Since then Management Studio has not been able to connect to the server. Is there any help (or hope for me for that matter), out there????? The following is the detailed error message: =================================== Cannot connect to LENOVO-E7A54767\SQLEXPRESS. =================================== A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (.Net SqlClient Data Provider) ------------------------------ For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&EvtSrc=MSSQLServer&EvtID=-1&LinkId=20476 ------------------------------ Error Number: -1 Severity: 20 State: 0 ------------------------------ Program Location: at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.SqlClient.SqlConnection.Open() at Microsoft.SqlServer.Management.UI.VSIntegration.ObjectExplorer.ObjectExplorer.ValidateConnection(UIConnectionInfo ci, IServerType server) at Microsoft.SqlServer.Management.UI.ConnectionDlg.Connector.ConnectionThreadUser()

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• Is there a maximum number of input controls that can be used on an HTML form?

  - by Rich

  I have an ambitious requirement for an asp.net 2.0 web page that contains a table (gridview), and each row in the grid contains 6 select (dropdown) controls for data entry. The number of rows that will be displayed is dependent upon the user's search parameters, which are specified in another area of the page. Unfortunately, with the default (and even basic) search parameters specified, the grid could contain several hundred rows. I've noticed that the browser, in this case IE8, starts behaving rather erratically once I reach a large number of rows -- no documented evidence for the number of rows where this begins to be a problem. For example, trying to view the source of the page results in a message from IE stating that there was a problem with the page that forced the browser to reload it, and I never get the source. Obviously the page loads and renders rather slowly also. I know that my solution is probably going to involve paging the gridview such that it only displays 20 or so rows per page, and I'll have to write code to handle the saving of changes in the dropdown values when the user changes pages. I can probably turn off viewstate on the gridview also. However, the question I really want to pose is this -- has anyone seen a documented rule indicating the maximum number of input controls that an HTML browser form is supposed to be able to contain? I could not find anything on the Internet after doing a search, and I suspect the answer may be whatever the browser can handle based on the machine configuration it is running on. Any rules of thumb you use? Thanks for any suggestions. Rich

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• Sorting a very large text file in Java

  - by Alice

  Hi, I have a large text file I need to sort in Java. The format is: word [tab] frequency [new line] The algorithm for sorting is: Read some of the file, filtering for purlely alphabetic words. Once you have X number of alphabetic words, call Collections.sort and write the result to a file. Repeat until you have finished reading the file. Start reading two sorted files, comparing line by line for the word with higher frequency, and writing at the same time to a new file as to not load much into your memory Repeat until all files are merged into one large file Right now I've divided the large file into smaller ones (sorted by descending frequency) with 10,000 lines each. I know I need to somehow merge these files back together, but I'm not sure how to go about this. I've created a LinkedList to keep track of all the files created. The algorithm says to compare each line in the two files, except I've tried a case where , say file1 = 8,6,5,3,1 and file2 = 9,8,8,8,8. Then if I compare them line by line I would get file3 = 9,8,8,6,8,5,8,3,8,1 which is incorrectly sorted (they should be in decreasing order). I think I'm misunderstanding some part of the algorithm. If someone could point out what I should do instead, I'd greatly appreciate it. Thanks. edit: Yes this is an assignment. We aren't allowed to increase memory unfortunately :(

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• Create an Oracle function that returns a table

  - by Craig

  I'm trying to create a function in package that returns a table. I hope to call the function once in the package, but be able to re-use its data mulitple times. While I know I create temp tables in Oracle, I was hoping to keep things DRY. So far, this is what I have: Header: CREATE OR REPLACE PACKAGE TEST AS TYPE MEASURE_RECORD IS RECORD ( L4_ID VARCHAR2(50), L6_ID VARCHAR2(50), L8_ID VARCHAR2(50), YEAR NUMBER, PERIOD NUMBER, VALUE NUMBER ); TYPE MEASURE_TABLE IS TABLE OF MEASURE_RECORD; FUNCTION GET_UPS( TIMESPAN_IN IN VARCHAR2 DEFAULT 'MONTLHY', STARTING_DATE_IN DATE, ENDING_DATE_IN DATE ) RETURN MEASURE_TABLE; END TEST; Body: CREATE OR REPLACE PACKAGE BODY TEST AS FUNCTION GET_UPS ( TIMESPAN_IN IN VARCHAR2 DEFAULT 'MONTLHY', STARTING_DATE_IN DATE, ENDING_DATE_IN DATE ) RETURN MEASURE_TABLE IS T MEASURE_TABLE; BEGIN SELECT ... INTO T FROM ... ; RETURN T; END GET_UPS; END TEST; The header compiles, the body does not. One error message is 'not enough values', which probably means that I should be selecting into the MEASURE_RECORD, rather than the MEASURE_TABLE. What am I missing?

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• Pipelining String in Powershell

  - by ChvyVele

  I'm trying to make a simple PowerShell function to have a Linux-style ssh command. Such as: ssh username@url I'm using plink to do this, and this is the function I have written: function ssh { param($usernameAndServer) $myArray = $usernameAndServer.Split("@") $myArray[0] | C:\plink.exe -ssh $myArray[1] } If entered correctly by the user, $myArray[0] is the username and $myArray[1] is the URL. Thus, it connects to the URL and when you're prompted for a username, the username is streamed in using the pipeline. Everything works perfectly, except the pipeline keeps feeding the username ($myArray[0]) and it is entered as the password over and over. Example: PS C:\Users\Mike> ssh xxxxx@yyyyy login as: xxxxx@yyyyy's password: Access denied xxxxx@yyyyy's password: Access denied xxxxx@yyyyy's password: Access denied xxxxx@yyyyy's password: Access denied xxxxx@yyyy's password: Access denied xxxxx@yyyyy's password: FATAL ERROR: Server sent disconnect message type 2 (protocol error): "Too many authentication failures for xxxxx" Where the username has been substituted with xxxxx and the URL has been substituted with yyyyy. Basically, I need to find out how to stop the script from piping in the username ($myArray[0]) after it has been entered once. Any ideas? I've looked all over the internet for a solution and haven't found anything.

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• UITableView overlaps with NavigationBar in Storyboard Setting on first run

  - by Evils

  I know this seems to be a duplicate question which has been around here many many times, but believe me, I tried all iOS7 and earlier fixes which sets the Layout to a different Edge configuration without any change. My Storyboard looks like this: -> Navigation Controller -> Tab Bar Controller -> MyTableViewController -> VCForCellOne With the first run of my application the UITableView overlaps with the source NavigationController as shown here: After clicking on one of my Cells which pushes the corresponding ViewController to the NavigationController and going back again, everything looks fine as shown here: So everything is as it should be after once pushing another ViewController to the NavigationController and then going back. Switching from Portrait to Landscape and back also fixes the layout problem and everything is layed out as it should be. My ViewController within the Storyboard looks like this: I left it the default value, so I don't know what goes wrong here. I hope you understand my problem here. There's no custom class ViewController here, so no additional code which messes up something here. Any help highly appreciated!

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• How can you exclude a large number of records in a cross db query using LINQ2SQL?

  - by tap

  So here is my situation: I have a vendor supplied DB we cannot modify and a custom db that imports data from the vendor app and acts on it. Once records are imported form the vendor app, they cannot appear on the list of records to be imported. Also we only want to display the 250 most recent records that have not been imported. What I originally started with was select the list of ids that have been imported from the custom db, and then query the vendor db, using the list of ids in a .Where(x = !idList.Contains(x.Id)) clause on the remote query. This worked up until we broke 2100 records imported into the custom db, as 2100 is the limit on the number of parameters that can be passed into SQL. After finding out this was the actual problem and not the 'invalid buffer'/'severe error' ADO.Net reported, my solution was to remove the first 2000 ids in the remote query, and then remove the remaining records in the local query. Having to pull back a large number of irrelevant records, just to exclude them, so I can get the correct 250 records seems very inelegant. Is there a better way to do this, short of doing a cross db stored procedure? Thanks in advance.

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• How can I make this jQuery plugin chainable after all image load events have completed?

  - by BumbleB2na

  [UPDATE] Solution I decided on: Decided that passing in a callback to the plugin will take care of firing an event once all images have completed loading. Chaining is also still possible. Updated Fiddle I am building a chainable jQuery plugin that can load images dynamically. (View the following code as a JSFiddle) Html: <img data-img-src="http://www.lubasf.com/blog/wp-content/uploads/2009/03/gnome.jpg" style="display: none" /> <img data-img-src="http://buffered.io/uploads/2008/10/gnome.jpg" style="display: none" /> Instead of adding in a src attribute, I give these images a data-img-src attribute. My plugin uses the value of that to fill the src. Also, these images are hidden to begin with. jQuery plugin: (function(jQuery) { jQuery.fn.loadImages = function() { var numToLoad = jQuery(this).length; var numLoaded = 0; jQuery(this).each(function() { if(jQuery(this).attr('src') == undefined) { return jQuery(this).load(function() { numLoaded++; if(numToLoad == numLoaded) return this; // attempt at making this plugin // chainable, after all .load() // events have completed. }).attr('src', jQuery(this).attr('data-img-src')); } else { numLoaded++; if(numToLoad == numLoaded) return this; // attempt at making this plugin // chainable, after all .load() // events have completed. } }); // this works if uncommented, but returns before all .load() events have completed //return this; }; })(jQuery); // I want to chain a .fadeIn() after all images have completed loading $('img[data-img-src]').loadImages().fadeIn(); Is there a way to make this plugin chainable, and have my fadeIn() happen after all images have loaded?

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• In Rails 3, how does one render HTML within a JSON response?

  - by ylg

  I'm porting an application from Merb 1.1 / 1.8.7 to Rails 3 (beta) / 1.9.1 that uses JSON responses containing HTML fragments, e.g., a JSON container specifying an update, on a user record, and the updated user row looks like . In Merb, since whatever a controller method returns is given to the client, one can put together a Hash, assign a rendered partial to one of the keys and return hash.to_json (though that certainly may not be the best way.) In Rails, it seems that to get data back to the client one must use render and render can only be called once, so rendering the hash to json won't work because of the partial render. From reading around, it seems one could put that data into a JSON .erb view file, with <%= render partial % in and render that. Is there a Rails-way of solving this problem (return JSON containing one or more HTML fragments) other than that? In Merb: only_provides :json ... self.status = 204 # or appropriate if not async return { 'action' => 'update', 'type' => 'user', 'id' => @user.id, 'html' => partial('user_row', format: :html, user: @user) }.to_json In Rails?

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• $this->url() to another subdomain

  - by Supertino7

  Hello, I created subdomain for my application. host_www.type = "Zend_Controller_Router_Route_Hostname" host_www.route = "www.mywebsite.com" host_www.defaults.module = "produits" host_www.defaults.controller = "produits" host_www.defaults.action = "index" fiche_boutique.route = "ficheboutique/:boutique" fiche_boutique.defaults.controller = "boutique" fiche_boutique.defaults.action = "fiche-boutique" fiche_boutique.defaults.module = "default" fiche_boutique.chain = "host_www" host_produits.type = "Zend_Controller_Router_Route_Hostname" host_produits.route = "produits.mywebsite.com" host_produits.defaults.module = "produits" host_produits.defaults.controller = "produits" host_produits.defaults.action = "index" fiche_produit.type = "Zend_Controller_Router_Route_Regex" fiche_produit.route = "([-\w]+).htm" fiche_produit.reverse = "%s.htm" fiche_produit.map.1 = "q" fiche_produit.defaults.module = "produits" fiche_produit.defaults.controller = "produits" fiche_produit.defaults.action = "voir-produit" fiche_produit.chain = "host" I don't know if the syntax in this zend config ini file is correct, in particular for routes chaining. Once I'm on this subdomain, urls constructed with $this-url() like this : <a href="<?= $this->url(array('boutique' => 1234), 'fiche_boutique', true) ?>"> Visit this store </a> still point to the subdomain produits.mywebsite.com, where I want it to point to www.mywebsite.com For the moment, I do this : <a href="http://www.mywebsite.com<?= $this->url(array('boutique' => 1234), 'fiche_boutique', true) ?>"> Visit this store </a> But it's not flexible at all. Is there a solution, a parameter to add, or my config file is wrong ? thanks in advance for your help.

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• How to handle javascript & css files across a site?

  - by Industrial

  Hi everybody, I have had some thoughts recently on how to handle shared javascript and css files across a web application. In a current web application that I am working on, I got quite a large number of different javascripts and css files that are placed in an folder on the server. Some of the files are reused, while others are not. In a production site, it's quite stupid to have a high number of HTTP requests and many kilobytes of unnecessary javascript and redundant css being loaded. The solution to that is of course to create one big bundled file per page that only contains the necessary information, which then is minimized and sent compressed (GZIP) to the client. There's no worries to create a bundle of javascript files and minimize them manually if you were going to do it once, but since the app is continuously maintained and things do change and develop, it quite soon becomes a headache to do this manually while pushing out new updates that features changes to javascripts and/or css files to production. What's a good approach to handle this? How do you handle this in your application?

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• Why am I needing to click twice on a WPF listbox item in order to fire a command?

  - by Donal

  Hi, I'm trying to make a standard WPF listbox be dynamically filled, and for each item in the list box to launch a command when clicked. Currently I have a working listbox, which can be filled and each item will fire the correct command, but in order to fire the command I have to click the list item twice. i.e, Click once to select the item, then click on the actual text to fire the command. As the list is dynamically created, I had to create a data template for the list items: <ListBox.ItemTemplate> <DataTemplate> <TextBlock Margin="4,2,4,2"> <Hyperlink TextDecorations="None" Command="MyCommands:CommandsRegistry.OpenPanel"> <TextBlock Text="{Binding}" Margin="4,2,4,2"/> </Hyperlink> </TextBlock> </DataTemplate> </ListBox.ItemTemplate> Basically, how do I remove the need to click twice? I have tried to use event triggers to fire the click event on the hyperlink element when the list box item is selected, but I can't get it to work. Or, is there a better approach to dynamically fill a listbox and attach commands to each list item? Thanks

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• How to append html only if the div is empty in jQuery?

  - by johnnyb3000

  I have this code for displaying content for login and registration in my PHP file: <?php // LOGIN PART ?> <div class="login-part"></div> <?php // REGISTRATION PART ?> <div class="registration-part"></div> And this in my js file: $(document).ready( function() { // FOR REGISTRATION $('span.logreg.reg').click(function () { $('div.registration-part').append('<p>Registration</p>'); }); // FOR LOGIN $('span.logreg.log').click(function () { // insert html $('div.login-part').append('<p>Login</p>'); }); }); Now, everytime I click on a span it shows the text login or registration, according to which of the span was clicked. Thats OK, however I need to add it only once, so when the user click more times on the span it will be not adding more text. Remove() or empty() is not an option, as far as I know, because I need the information inside input boxes (there will be input boxes later for inserting user info) to stay there and not be deleted if the user click accidentally on the span again. It can however delete the html inside the div, if he clicks on another span. E.g. if span.log is active, after clicking on span.log nothing happens, but if he clicks on span.reg the html inside div.login-part will be removed and registration text will appear. How to do something like this?

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• iPhone application purchase verification -- possible?

  - by Sedate Alien

  The iPhone 3.0 SDK's StoreKit.framework provides support for in-app purchases to give the user additional content, functionality and so on. It is possible for an app to send the transactionReceipt property of SKPaymentTransaction objects to the developer's server for verification of successful purchasing before granting service. Is there any analogous SDK to verify the initial application purchase itself? A developer that wishes for their server to only provide services to genuine applications (i.e. not pirated) without using IAP could do so by verifying the application in this manner, e.g. ensure that only users with the correct transactionReceipt are catered for. I understand that this approach would still be vulnerable to replay attacks; a dedicated group of pirates could share a valid transactionReceipt. However, my server provides a consumable service to users, i.e. once they've connected and done the work, it needn't work a second time so replay attacks are nullified. The service that my app provides is relatively niche. I could distribute it on the App Store as a free application that requires at least one IAP to do anything useful, but I am lead to believe that this would be a very unpopular move among users as it would be considered misleading. If I distribute it as a paid app, I do not know how to ensure that only genuine apps can access the webservice. This is important as every invocation of the webservice costs me money! What are my options?

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• How can I pass an array resulting from a Perl method by reference?

  - by arareko

  Some XML::LibXML methods return arrays instead of references to arrays. Instead of doing this: $self->process_items($xml->findnodes('items/item')); I want to do something like: $self->process_items(\$xml->findnodes('items/item')); So that in process_items() I can dereference the original array instead of creating a copy: sub process_items { my ($self, $items) = @_; foreach my $item (@$items) { # do something... } } I can always store the results of findnodes() into an array and then pass the array reference to my own method, but let's say I want to try a reduced version of my code. Is that the correct syntax for passing the method results or should I use something different? Thanks! EDIT: Now suppose I want to change process_items() to process_item() so I can do stuff on a single element of the referenced array inside a loop. Something like: $self->process_item($_) for ([ $xml->findnodes('items/item') ]); This doesn't work as process_item() is executed only once because a single value is passed to the for loop (the reference to the array from findnodes()). What's the proper way of using $_ in this case?

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• A question of long-running and disruptive branches

  - by Matt Enright

  We are about to begin prototyping a new application that will share some existing infrastructure assemblies with an existing application, and also involve a significant subset of the existing domain model. Parts of the domain model will likely undergo some serious changes for this new application, and the endgame for all of this, once the new application has been fully specified and is launch-ready is that we would like to re-unify the models of the two applications (as well as share a database, link functionality, etc.), but for the duration of development, prototyping, etc, we will be using a separate database so that we can change things without worrying about impact to development or use of the existing application. Since it is a prototype, there will be a pretty long window during which serious changes or rearchitecturing can occur as product management experiments with different workflows, different customer bases are surveyed, and we try and keep up. We have already made a Subversion branch, so as to not impact concurrent development on the mature application, and are toying with 2 potential ways of moving forward with this: Use the svn branch as the sole mechanism of separation. Make our changes to the existing domain models, and evaluate their impact on the existing application (and make requisite changes to ProjectA) when we have established that our long-running side branch is stable enough for re-entry to trunk. "Fork" the shared code (temporarily): Copy ProjectA.Entities to NewProject.Entities, and treat all of the NewProject code as self-contained. When all of the perturbations around the model have died down and we feel satisfied, manually re-integrate the changes (as granular or sweeping as warranted) back into ProjectA.Entities, updating ProjectA to use the improved models at each step (this can take place either before or after the subversion merge has occurred). The subversion merge will then not handle recombination of any of the heavy changes here. Note: the "fork" method only applies to the code we see significant changes in store for, and whose modification will break ProjectA - shared infrastructure stuff for example, we would just modify in place (on our branch) and let the merge sort out. Development is hard, go shopping. Naturally, after not coming to an agreement, we're turning it over to the oracle of power that is SO. Any experience with any of these methods, pain points to watch out for, something new entirely?

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• JavaScript sleep

  - by Diazath

  yes, i know - that question has thousands of answers. please, don't tell me about "setTimeout" method becasuse - yes, everything is possible with that but not so easy as using sleep() method. for example: function fibonacci(n) { console.log("Computing Fibonacci for " + n + "..."); var result = 0; //wait 1 second before computing for lower n sleep(1000); result = (n <= 1) ? 1 : (fibonacci(n - 1) + fibonacci(n - 2)); //wait 1 second before announcing the result sleep(1000); console.log("F(" + n + ") = " + result); return result; } if you know how to get the same result using setTimeout - tell me ;) fibanacci is pretty easy task, because there not more than 2 recursions, but how about n-recursions (like fib(1) + fib(2) + .. + fib(n) and sleep after every "+"? nah, sleep would be muuuuuch easier. but still i can't get working example of implementing it. while (curr - start < time) { curr = (...) } is tricky, but it won't work (just stops my browser and then throw all console.logs at once).

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• Why can't multiple programmatically generated FilteringSelect's share a single store?

  - by yarmiganosca

  Before you ask, a MultiSelect wouldn't really be intuitive for the user in this instance. I have an object, with an array as its value for 'items', that's provided on the page in a var statement. I also have a function that generates and places dijit.form.FilteringSelects and is triggered on a certain button's click event. Every one of these selects should have the aformentioned object as their 'store' attribute. If I write store: new dojo.data.ItemFileReadStore({ data: object_name }), in my select initialization code, I get weird behavior: I click the generate button 2 times and get 2 FilteringSelects (call them A,B). I click on B's dropdown piece, and the menu appears attached to B. Then I click on A's dropdown button, and menu appears attached to A. If I then go back and click on B's dropdown button again, nothing happens (well not nothing; an error gets thrown). However, if instead, I have data: {items: array_literal} everything works fine, and I switch back and forth between the 2 as much as I want. As the data: statement appears once in the javascript code, this isn't a big deal (now that I have a workaround at least). It is however, exceedingly odd. I attempted to dig into the source code, to no avail.Anybody have any idea what's going on here?

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• Core Data Errors vs Exceptions Part 3

  - by John Gallagher

  My question is similar to this one. Background I'm creating a large number of objects in a core data store using NSOperations to speed things up. I've followed all the Core Data multithreading rules - I've got a single persistent store coordinator and a managed object context per thread that on save is merging back to the main managed object context. The Problem When the number of threads running at once is more than 1, I get the exception logged on save of my core data store: NSExceptionHandler has recorded the following exception: NSInternalInconsistencyException -- optimistic locking failure What I've Tried My code that creates new entities is quite complex - it makes entities that have relationships with other entities that could be being created in a separate thread. If I replace my object creation routine with some very simple code just making non-related entries, everything works perfectly. Initially, as well as the exceptions, I was getting a save error saying core data couldn't save due to the merge failing. I read the docs and realised I needed a merge policy on the Managed Object Context I was saving to. I set this up and as this question states, the save error goes away, but the exception remains. My Question Do I need to worry about these exceptions? If I do need to get rid of the exceptions, any ideas on how I do it?

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• Best way to run multiple queries per second on database, performance wise?

  - by Michael Joell

  I am currently using Java to insert and update data multiple times per second. Never having used databases with Java, I am not sure what is required, and how to get the best performance. I currently have a method for each type of query I need to do (for example, update a row in a database). I also have a method to create the database connection. Below is my simplified code. public static void addOneForUserInChannel(String channel, String username) throws SQLException { Connection dbConnection = null; PreparedStatement ps = null; String updateSQL = "UPDATE " + channel + "_count SET messages = messages + 1 WHERE username = ?"; try { dbConnection = getDBConnection(); ps = dbConnection.prepareStatement(updateSQL); ps.setString(1, username); ps.executeUpdate(); } catch(SQLException e) { System.out.println(e.getMessage()); } finally { if(ps != null) { ps.close(); } if(dbConnection != null) { dbConnection.close(); } } } And my DB connection private static Connection getDBConnection() { Connection dbConnection = null; try { Class.forName(DB_DRIVER); } catch (ClassNotFoundException e) { System.out.println(e.getMessage()); } try { dbConnection = DriverManager.getConnection(DB_CONNECTION, DB_USER,DB_PASSWORD); return dbConnection; } catch (SQLException e) { System.out.println(e.getMessage()); } return dbConnection; } This seems to be working fine for now, with about 1-2 queries per second, but I am worried that once I expand and it is running many more, I might have some issues. My questions: Is there a way to have a persistent database connection throughout the entire run time of the process? If so, should I do this? Are there any other optimizations that I should do to help with performance? Thanks

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• CakePHP 2.0: how to access properties of the parent object?

  - by PaulJ

  I just started learning CakePHP 2.0 a few days ago, and there's one thing that is leaving me stumped: say I have an User model and a Posts model: class User extends AppModel { public $name = "User"; public $hasMany=array( 'Post' => array( 'className' => 'Post', 'foreignKey' => 'author_id' ) ); } class Post extends AppModel { public $name = 'Post'; public $belongsTo = array( 'className' = 'User', 'foreignKey' = 'author_id', ); } (Where "author_id" is the foreign key in the posts table that references the Users table's primary key). And now, in the PostsController, I want to access the properties of the user that owns the current post (to show his display name, for example). What would be the proper syntax? I tried: $this->Post->User->find('first', array('conditions' => array('User.id' => "$usuario"))) But it didn't work (I guess it's because the User is the parent of the Post object, not its child). Or should CakePHP load everything automatically, once you've declared the $hasMany and $belongsTo relationships?

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• iPad search bar bad memory access?

  - by Geoff Baum

  Hello all, So I am trying to implement a search bar in my app and am very close but can't seem to figure out where this memory error is occurring. This is what part of my search method looks like: filters = [[NSMutableArray alloc] init]; NSString *searchText = detailSearch.text; NSMutableArray *searchArray = [[NSMutableArray alloc] init]; // Normally holds the object (ex: 70 locations) searchArray = self.copyOfFilters ; //This is the line that is breaking after ~2-3 letters are entered in the search for (NSString *sTemp in searchArray) { NSRange titleResultsRange = [sTemp rangeOfString:searchText options:NSCaseInsensitiveSearch]; if (titleResultsRange.length > 0) [filters addObject:sTemp]; } displayedFilters = filters; copyOfFilters is a deep copy of the displayed filters that appear when the view first loads via: self.copyOfFilters = [[NSMutableArray alloc] initWithArray:displayedFilters copyItems:YES]; I have traced through the entry of letters and it is accurate after 2 letters, but once you try and enter a letter after a space in the search bar, it crashes. The value of copyOfFilters = {(int)[$VAR count]} objects. Does anyone know what may be causing this? Thanks!

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• PHP - advice for java HashMap alternative in php?

  - by teutara

  I know it is super noob and will be answered in no time, but I could not figure.. sorry for any inconvenience.. Here is the thing: ID colA colB Length 1 seq1 seq11 1 2 seq1 seq11 11 3 seq3 seq33 21 4 seq3 seq33 14 I have a db with this kind of a table, has more than 10M rows. I want to loop though colA first, get the relevant colB value, and check if there are any other occurrences of the same value. For example in colB (seq11) there are 2 occurrences of colA(seq1), this time I have to combine those and output the sum of the length. Similar to this: ID colA colB Length 1 seq1 seq11 12 2 seq3 seq33 35 I am a bit java guy, but because my colleague has written everything in php and this will be just an adding, i need a php solution. With java i would have used hashmap, so that I would have the colA data once and just increment the value of "Length Column".. I know it is not a proper question, but.. Thank you in advance.. $$$$$$$$$$ EDIT $$$$$$$$$$ I tried this query in order to group by occurences: SELECT COUNT(*) SeqName FROM SeqTable GROUP BY SeqName HAVING COUNT(*)>0;

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• How can we find second maximum from array efficiently?

  - by Xinus

  Is it possible to find the second maximum number from an array of integers by traversing the array only once? As an example, I have a array of five integers from which I want to find second maximum number. Here is an attempt I gave in the interview: #define MIN -1 int main() { int max=MIN,second_max=MIN; int arr[6]={0,1,2,3,4,5}; for(int i=0;i<5;i++){ cout<<"::"<<arr[i]; } for(int i=0;i<5;i++){ if(arr[i]>max){ second_max=max; max=arr[i]; } } cout<<endl<<"Second Max:"<<second_max; int i; cin>>i; return 0; } The interviewer, however, came up with the test case int arr[6]={5,4,3,2,1,0};, which prevents it from going to the if condition the second time. I said to the interviewer that the only way would be to parse the array two times (two for loops). Does anybody have a better solution?

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