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• ????????????????

  - by Yusuke.Yamamoto

  ????·???? ?????:??????·?????? ~???????????Platinum???????????~ Pickup!:????????????????????? ???????|??????????|???????? ????????:?Oracle DB?????????????????????Windows?VMware?? ???? Oracle Technology Network, ????/????, ??IT???????·?????????????? View RSS feed ????? ????? Oracle?????????????????????????!???????????? View RSS feed ????? ???? ????????? Oracle Database ?????? ??????? ?????????(????????, ???, etc) ????????(???, REDO, ????????, etc) ????·????????????????? ????·?????????(??, etc) ????????????? ???????????????????·?????? ??????? ???? ????????·??SQL Server Windows Server ??????????PL/SQL|Java|.NET|PHP ??/??? ORACLE MASTER ???? DWH(?????????)??·?? ????? ?????(SAN, NAS, SSD, etc) ??·??????? Oracle Database Oracle Database 11g Release 2(11gR2) Oracle Database Standard Edition ????????: Advanced Compression ?????????: Advanced Security Application Express(APEX) Automatic Storage Management(ASM) SSD???Oracle???: Database Smart Flash Cache ??????????: Data Guard Data Pump Oracle Data Provider for .NET(ODP.NET) Partitioning(???????/?????????) DB????: Real Application Clusters(RAC) Real Application Testing Recovery Manager(RMAN) SQL*Loader|SQL*Plus|Statspack ??????|????????|???????? Amazon EC2|Microsoft Excel MSFC/MSCS(Microsoft Cluster Service) Exadata|Database Firewall SQL Developer ?????DB: TimesTen In-Memory Database Oracle Fusion Middleware Java Oracle Coherence Oracle Data Integrator(ODI) Oracle GoldenGate Oracle JRockit JVM Oracle WebLogic Server Oracle Enterprise Manager ????????????: Oracle Application Testing Suite Oracle Solaris DTrace|ZFS|???/???? Oracle VM Server for x86 ?????? ???????? ?????????Oracle???????????????·????????????????? ?????????(??·??????) Oracle Direct Seminar(?????????) OTN??????(??????) ???????(????????) Oracle University(??) ??????! View RSS feed ????? ?????? ????? ?????? ?????|?Sun?? ???????? OTN???????? OTN(????) ?????? ???? OTN???|???? OTN????? ?????? ?????? ???????? ???? ???????

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• OpenXML SDK: Make Excel recalculate formula

  - by chiccodoro

  I update some cells of an Excel spreadsheet through the Microsoft Office OpenXML SDK 2.0. Changing the values makes all cells containing formula that depend on the changed cells invalid. However, due to the cached values Excel does not recalculate the formular, even if the user clicks on "Calculate now". What is the best way to invalidate all dependent cells of the whole workbook through the SDK? So far, I've found the following code snippet at http://cdonner.com/introduction-to-microsofts-open-xml-format-sdk-20-with-a-focus-on-excel-documents.htm: public static void ClearAllValuesInSheet (SpreadsheetDocument spreadSheet, string sheetName) { WorksheetPart worksheetPart = GetWorksheetPartByName(spreadSheet, sheetName); foreach (Row row in worksheetPart.Worksheet. GetFirstChild().Elements()) { foreach (Cell cell in row.Elements()) { if (cell.CellFormula != null && cell.CellValue != null) { cell.CellValue.Remove(); } } } worksheetPart.Worksheet.Save(); } Besides the fact that this snippet does not compile for me, it has two limitations: It only invalidates a single sheet, although other sheets might contain dependent formula It does not take into account any dependencies. I am looking for a way that is efficient (in particular, only invalidates cells that depend on a certain cell's value), and takes all sheets into account. Update: In the meantime I have managed to make the code compile & run, and to remove the cached values on all sheets of the workbook. (See answers.) Still I am interested in better/alternative solutions, in particular how to only delete cached values of the cells that actually depend on the updated cell.

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• iPhone: How to Display Text from UIWebView HTML Document in a UITextView

  - by ArgMan

  I have an RSS feed that gets arranged in a UITableView which lets the user select a story that loads in a UIWebView. However, I'd like to stop using the UIWebView and just use a UITextView or UILabel. This png is what I am trying to do (just display the various text aspects of a news story): I have tried using: NSString *myText = [webView stringByEvaluatingJavaScriptFromString:@"document.documentElement.textContent"]; and assigning the string to a UILabel but it doesn't work from where I am implementing it in webViewDidFinishLoad (--is that not the proper place?). I get a blank textView and normal webView. If I overlay a UITextView on top of a UIWebView on its own (that is, a webView that just loads one page), the code posted above works displays the text fine. The problem arises when I try to process the RSS feed . I've been stuck wondering why this doesn't work as it should for a few days now. If you have a better, more efficient way of doing it then placing the code in webViewDidFinishLoad, please let me know! Does it go in my didSelectRowAtIndexPath? Thank you very much in advance!

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• LINQ To SQL ignore unique constraint exception and continue

  - by Martin

  I have a single table in a database called Users Users ------ ID (PK, Identity) Username (Unique Index) I have setup a unique index on the Username table to prevent duplicates. I am then enumerating through a collection and creating a new user in the database for each item. What I want to do is just insert a new user and ignore the exception if the unique key constraint is violated (as it's clearly a duplicate record in that case). This is to avoid having to craft where not exists kind of queries. First off, is this going to be any more efficient or should my insert code be checking for duplicates instead? I'm drawn more to the database having that logic as this prevents any other type of client from inserting duplicate data. My other issue is related to LINQ To SQL. I have the following code: public class TestRepo { DatabaseDataContext database = new DatabaseDataContext(); public void Add(string username) { database.Users.InsertOnSubmit(new User() { Username = username }); } public void Save() { database.SubmitChanges(); } } And then I iterate over a collection and insert new users, ignoring any exceptions: TestRepo repo = new TestRepo(); foreach (var name in new string[] { "Tim", "Bob", "John" }) { try { repo.Add(name); repo.Save(); } catch { } } The first time this is run, great I have three users in the table. If I remove the second one and run this code again, nothing is inserted. I expected the first insert to fail with the exception, the second to succeed (as I just removed that item from the DB) and the third to then fail. What seems to be happening is that once the SqlException is thrown (even though the loop continues to iterate) all of the next inserts fail - even when there isn't a row in the table that would cause a unique violation. Can anyone explain this? P.S. The only workaround I could find was to instantiate the repo each time before the insert, then it worked exactly as excepted - indicating that it's something to do with the LINQ To SQL DataContext. Thanks.

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• What is the equivalent of memset in C#?

  - by Jedidja

  I need to fill a byte[] with a single non-zero value. How can I do this in C# without looping through each byte in the array? Update: The comments seem to have split this into two questions - Is there a Framework method to fill a byte[] that might be akin to memset What is the most efficient way to do it when we are dealing with a very large array? I totally agree that using a simple loop works just fine, as Eric and others have pointed out. The point of the question was to see if I could learn something new about C# :) I think Juliet's method for a Parallel operation should be even faster than a simple loop. Benchmarks: Thanks to Mikael Svenson: http://techmikael.blogspot.com/2009/12/filling-array-with-default-value.html It turns out the simple for loop is the way to go unless you want to use unsafe code. Apologies for not being clearer in my original post. Eric and Mark are both correct in their comments; need to have more focused questions for sure. Thanks for everyone's suggestions and responses.

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• How to add dynamic profile fields in Invision Power Board?

  - by user361908

  I run a game server and want to link the persons in game character name and stats to Invision Power Board. I've setup IPB so players currently login with their in game login. That means their username on the forum is the same as their username for the game. They can have multiple characters on 1 account so ideally I'd like to allow them to choose a main character and display an actual image of that character and allow them to display other characters if they are online. Currently I'm doing something like this by hacking profileFields.php but it's messy and not very efficient on the user or server end. My code currently uses 2 custom fields which the player can enter their character names in. To display only their main character they enter the name in the first field. To also display other characters if they are online they enter the same name into the second field. To resolve the IDs I have to run a lot of queries. I know PHP but I am not familiar with IPBs code at all. I just need pointed in a direction where I can combine the 2 fields into 1 field. tl;dr: Here is my setup: Invision Power Board 3 Data is stored in MySQL on the same server the forum is hosted on. Usernames on the forum are identical to usernames in the game Here is a breakdown of what I'd like to do: In the edit profile section I need to resolve the forum username to the games account id then: Display a list of characters and allow them to choose which characters they want to display if they are online as well as a default character that will be displayed if none are online. In the posts user info pane: Display the online character or the default if none are online. Here is what I need to know: How to generate a list of characters in the profile edit form and allow selection (checkbox) of each character to display as well as the selection of a default character (radio or dropdown?) How to fetch the data and place it in the posts user info pane

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• Binary serialization/de-serialization in C++ and C#

  - by 6pack kid

  Hello. I am working on a distributed application which has two components. One is written in standard C++ (not managed C++) and the other one is written in C#. Both are communicating via a message bus. I have a situation in which I need to pass objects from C++ to C# application and for this I need to serialize those objects in C++ and de-serialize them in C# (something like marshaling/un-marshaling in .NET). I need to perform this serialization in binary and not in XML (due to performance reasons). I have used Boost.Serialization to do this when both ends were implemented in C++ but now that I have a .NET application on one end, Boost.Serialization is not a viable solution. I am looking for a solution that allows me to perform (de)serialization across C++ and .NET boundary i.e., cross platform binary serialization. I know I can implement the (de)serialization code in a C++ dll and use P/Invoke in the .NET application, but I want to keep that as a last resort. Also, I want to know if I use some standard like gzip, will that be efficient? Are there any other alternatives to gzip? What are the pros/cons of them? Thanks

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• Development Environment in a VM against an isolated development/test network

  - by bart

  I currently work in an organization that forces all software development to be done inside a VM. This is for a variety of risk/governance/security/compliance reasons. The standard setup is something like: VMWare image given to devs with tools installed VM is customized to suit project/stream needs VM sits in a network & domain that is isolated from the live/production network SCM connectivity is only possible through dev/test network Email and office tools need to be on live network so this means having two separate desktops going at once Heavyweight dev tools in use on VMs so they are very resource hungry Some problems that people complain about are: Development environment runs slower than normal (host OS is windows XP so memory is limited) Switching between DEV machine and Email/Office machine is a pain, simple things like cut and paste are made harder. This is less efficient from a usability perspective. Mouse in particular doesn't seem to work properly using VMWare player or RDP. Need a separate login to Dev/Test network/domain Has anyone seen or worked in other (hopefully better) setups to this that have similar constraints (as mentioned at the top)? In particular are there viable options that would remove the need for running stuff in a VM altogether?

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• How do you keep all your languages straight?

  - by Chris Blackwell

  I think I'm going a little crazy. Right now, I'm working with the following languages (I was just doing a mental inventory): C++ - our game engine Assembler - low level debugging and a few co-processor specific routines Lua - our game engine scripting language HLSL - for shaders Python - our build system and utility tools Objective C/C++ - game engine platform code for Mac and iPhone C# - A few tools developed in our overseas office ExtendScript - Photoshop exporting tools ActionScript - UI scripting VBScript - some spreadsheet related stuff PHP - some web related stuff SQL - some web and tool related stuff On top of this are the plethora of API's that often have many different ways of doing the same thing: std library, boost, .NET, wxWidgets, Cocoa, Carbon, native script libraries for Python, Lua, etc, OpenGL, Direct3d, GDI, Aqua, augh! I find myself inadvertently conflating languages and api's, not realizing what I'm doing until I get syntax errors. I feel like I can't possibly keep up with it, and I can't possibly be proficient in all of these areas. Especially outside the realm of C++ and Python, I find myself programming more by looking at manuals that from memory. Do you have a similar problem? Ideas for compartmentalizing so you're more efficient? Deciding where you want to stay proficient? Organizational tips? Good ways to remember when you switch from Lua to C++ you need to start using semi-colons again? Rants on how complicated we programmers have made things for ourselves? Any ideas welcome!

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• In Java Concurrency In Practice by Brian Goetz, why is the Memoizer class not annotated with @ThreadSafe?

  - by dig_dug

  Java Concurrency In Practice by Brian Goetz provides an example of a efficient scalable cache for concurrent use. The final version of the example showing the implementation for class Memoizer (pg 108) shows such a cache. I am wondering why the class is not annotated with @ThreadSafe? The client, class Factorizer, of the cache is properly annotated with @ThreadSafe. The appendix states that if a class is not annotated with either @ThreadSafe or @Immutable that it should be assumed that it isn't thread safe. Memoizer seems thread-safe though. Here is the code for Memoizer: public class Memoizer<A, V> implements Computable<A, V> { private final ConcurrentMap<A, Future<V>> cache = new ConcurrentHashMap<A, Future<V>>(); private final Computable<A, V> c; public Memoizer(Computable<A, V> c) { this.c = c; } public V compute(final A arg) throws InterruptedException { while (true) { Future<V> f = cache.get(arg); if (f == null) { Callable<V> eval = new Callable<V>() { public V call() throws InterruptedException { return c.compute(arg); } }; FutureTask<V> ft = new FutureTask<V>(eval); f = cache.putIfAbsent(arg, ft); if (f == null) { f = ft; ft.run(); } } try { return f.get(); } catch (CancellationException e) { cache.remove(arg, f); } catch (ExecutionException e) { throw launderThrowable(e.getCause()); } } } }

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• Using db4o with multiple application instances under medium trust

  - by Anders Fjeldstad

  I recently stumbled over the object database engine db4o which I think looks really interesting. I would like to use it in an ASP.NET MVC application that will be deployed to a shared hosting environment under medium trust. Because of the trust level, I'm restricted to using db4o in embedded/in-process mode. That in itself should be no problem, but the hosting provider also transparently runs each web application in multiple (load-balanced) server instances with shared storage, which I would say is normally a very nice feature for a $10/month hoster. However, since an instance of a db4o server with write access (whether in-process or networked) locks the underlying database file, having multiple instances of the application using the same file won't work (or at least I can't see how it would). So the question is: is it possible to use db4o in this specific environment? I have considered letting each application have its own database which is synchronized with a master database using replication (dRS), but that approach will most likely end up with very frequent bi-directional replication (read master changes at beginning of each request, write to master after each change) which I don't think will be very efficient. Summary of the web application/environment characteristics: Read-intensive (but not entirely read-only) Some delay (a few seconds) is acceptible between the time that a change is made and the time when the change shows up in all the application instances' data Must run in medium trust No guarantee that the load-balancer uses "sticky sessions" All suggestions are much appreciated!

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• CodeIgniter/PHP - Calling a view from within a view

  - by Jack W-H

  Hi Folks Basically for my webapp I'm trying to organise it a bit better. As it at the moment, every time I want to load a page, I have to do it from my controller like so: $this->load->view('subviews/template/headerview'); $this->load->view('subviews/template/menuview'); $this->load->view('The-View-I-Want-To-Load'); $this->load->view('subviews/template/sidebar'); $this->load->view('subviews/template/footerview'); As you can tell it's not really very efficient. So I thought I'd create one 'master' view - It's called template.php. This is the contents of the template view: <?php $view = $data['view']; $this->load->view('subviews/template/headerview'); $this->load->view('subviews/template/menuview'); $this->load->view($view); $this->load->view('subviews/template/sidebar'); $this->load->view('subviews/template/footerview'); ?> And then I thought I'd be able to call it from a controller like this: $data['view'] = 'homecontent'; $this->load->view('template',$data); Unfortunately I simply cannot make this work. Does anyone have any ways around this or fixes I can put into place? I've tried putting ""s and ''s around $view in template.php but that makes no difference. The usual error is "Undefined variable: data" or "Cannot load view: $view.php" etc. Thanks folks! Jack

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• Combinations into pairs

  - by Will

  I'm working on a directed network problem and trying to compute all valid paths between two points. I need a way to look at paths up to 30 "trips" (represented by an [origin, destination] pair) in length. The full route is then composed of a series of these pairs: route = [[start, city2], [city2, city3], [city3, city4], [city4, city5], [city5, city6], [city6, city7], [city7, city8], [city8, stop]] So far my best solution is as follows: def numRoutes(graph, start, stop, minStops, maxStops): routes = [] route = [[start, stop]] if distance(graph, route) != "NO SUCH ROUTE" and len(route) >= minStops and len(route) <= maxStops: routes.append(route) if maxStops >= 2: for city2 in routesFromCity(graph, start): route = [[start, city2],[city2, stop]] if distance(graph, route) != "NO SUCH ROUTE" and len(route) >= minStops and len(route) <= maxStops: routes.append(route) if maxStops >= 3: for city2 in routesFromCity(graph, start): for city3 in routesFromCity(graph, city2): route = [[start, city2], [city2, city3], [city3, stop]] if distance(graph, route) != "NO SUCH ROUTE" and len(route) >= minStops and len(route) <= maxStops: routes.append(route) if maxStops >= 4: for city2 in routesFromCity(graph, start): for city3 in routesFromCity(graph, city2): for city4 in routesFromCity(graph, city3): route = [[start, city2], [city2, city3], [city3, city4], [city4, stop]] if distance(graph, route) != "NO SUCH ROUTE" and len(route) >= minStops and len(route) <= maxStops: routes.append(route) if maxStops >= 5: for city2 in routesFromCity(graph, start): for city3 in routesFromCity(graph, city2): for city4 in routesFromCity(graph, city3): for city5 in routesFromCity(graph, city4): route = [[start, city2], [city2, city3], [city3, city4], [city4, city5], [city5, stop]] if distance(graph, route) != "NO SUCH ROUTE" and len(route) >= minStops and len(route) <= maxStops: routes.append(route) return routes Where numRoutes is fed my network graph where numbers represent distances: [[0, 5, 0, 5, 7], [0, 0, 4, 0, 0], [0, 0, 0, 8, 2], [0, 0, 8, 0, 6], [0, 3, 0, 0, 0]] a start city, an end city and the parameters for the length of the routes. distance checks if a route is viable and routesFromCity returns the attached nodes to each fed in city. I have a feeling there's a far more efficient way to generate all of the routes especially as I move toward many more steps, but I can't seem to get anything else to work.

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• How to configure properly IntelliJ IDEA for deployment of JBoss Seam project?

  - by Piotr Kochanski

  I would like to use IntelliJ IDEA for development of JBoss Seam project. seam-gen is creating the project stub, however the stub is not complete. In particular it is not clear how to deploy such project. First of all I had to define manually web project facelet and add libraries to its deployment definition. The other problem was persistence.xml file. In the Seam generated project it does not exists, since Ant is using one of the persistence-dev.xml, persistence-prod.xml, persistence-test.xml files, changing its name, depending on deployment type (which is ok). Obviously I can create persistence.xml by hand, but it goes againts Seam way of development. Finally I decided to use directly ant, which is not partucularly comfortable. All these tweaks made me think that I am doing something wrong from the IntelliJ IDEA point of view. What is the efficient way of configuring IntelliJ for usage with JBoss Seam (deployment, in particular)? I am using JBoss Seam 2.1.1, Intellij 8.1.4, JBoss 4.3.3

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• Example usage of a custom delegate in c#

  - by Freakishly

  Hi, I found this question on SO about a tree implementation in C#. I have no idea about delegates and I was wondering how the following code could be used to implement a tree. Also, what would be the most efficient way to keep a track of parent nodes? delegate void TreeVisitor<T>(T nodeData); class NTree<T> { T data; LinkedList<NTree<T>> children; public NTree(T data) { this.data = data; children = new LinkedList<NTree<T>>(); } public void addChild(T data) { children.AddFirst(new NTree<T>(data)); } public NTree<T> getChild(int i) { foreach (NTree<T> n in children) if (--i == 0) return n; return null; } public void traverse(NTree<T> node, TreeVisitor<T> visitor) { visitor(node.data); foreach (NTree<T> kid in node.children) traverse(kid, visitor); } }

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• Versioning freindly, extendible binary file format

  - by Bas Bossink

  In the project I'm currently working on there is a need to save a sizeable data structure to disk. Being in optimist I thought their must be a standard solution for such a problem however upto now I haven't found a solution that satisfies the following requirements: .net 2.0 support, preferably with a foss implementation version friendly (this should be interpreted as reading an old version of the format should be relatively simple if the changes in the underlying data structure are simple, say adding/dropping fields) ability to do some form of random access where part of the data can be extended after initial creation (think of this as extending intermediate results) space and time efficient (xml has been excluded as option given this requierement) Options considered so far: Protocol Buffers : was turned down by verdict of the documentation about Large Data Sets since this comment suggest adding another layer on top, this would call for additional complexity which I wish to have handled by the file format itself. HDF5,EXI : do not seem to have .net implementations SQLite : the data structure at hand would result in a pretty complex table structure that seems to heavyweight for the intended use BSON : does not appear to support requirement 3. Fast Infoset : only seems to have buyware .net implementations Any recommendations or pointers are greatly appreciated. Furthermore if you believe any of the information above is not true please provide pointers/examples to proove me wrong.

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• General Web Programming/designing Question: ?

  - by Prasad

  hi, I have been in web programming for 2 years (Self taught - a biology researcher by profession). I designed a small wiki with needed functionalities and a scientific RTE - ofcourse lot is expected. I used mootools framework and AJAX extensively. I was always curious when ever I saw the query strings passed from URL. Long encrypted query string directly getting passed to the server. Especially Google's design is such. I think this is the start of providing a Web Service to a client - I guess. Now, my question is : is this a special, highly professional, efficient / advanced web design technique to communicate queries via the URL ? I always felt that direct URL based communication is faster. I tried my bit and could send a query through the URL directly. here is the link: http://sgwiki.sdsc.edu/getSGMPage.php?8 By this , the client can directly link to the desired page instead of searching and / or can automate. There are many possibilities. The next request: Can I be pointed to such technique of web programming? oops: I am sorry, If I have not been able to convey my request clearly. Prasad.

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• Is there a way to receive receive data as unsugned char over UDP on QT

  - by user269037

  I need to send floating point numbers using UDP connection to a QT application. Now in QT the only function available is qint64 readDatagram ( char * data, qint64 maxSize, QHostAddress * address = 0, quint16 * port = 0 ) which accepts data in the form of signed character buffer. I can convert my float into a string and send it but it will obviously not be very efficient converting a 4 byte float into a much longer sized character buffer. I got hold of these 2 functions to convert a 4 byte float into an unsinged 32 bit integer to transfer over network which works fine for a simple c++ udp program but for QT I need to receive the data as unsigned char. Is it possible to avoid converting the floatinf point data into a string and then sending it ?? uint32_t htonf(float f) { uint32_t p; uint32_t sign; if (f < 0) { sign = 1; f = -f; } else { sign = 0; } p = ((((uint32_t)f)&0x7fff)<<16) | (sign<<31); // whole part and sign p |= (uint32_t)(((f - (int)f) * 65536.0f))&0xffff; // fraction return p; } float ntohf(uint32_t p) { float f = ((p16)&0x7fff); // whole part f += (p&0xffff) / 65536.0f; // fraction if (((p>>31)&0x1) == 0x1) { f = -f; } // sign bit set return f; }

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• Remove duplicates from a sorted ArrayList while keeping some elements from the duplicates

  - by js82

  Okay at first I thought this would be pretty straightforward. But I can't think of an efficient way to solve this. I figured a brute force way to solve this but that's not very elegant. I have an ArrayList. Contacts is a VO class that has multiple members - name, regions, id. There are duplicates in ArrayList because different regions appear multiple times. The list is sorted by ID. Here is an example: Entry 0 - Name: John Smith; Region: N; ID: 1 Entry 1 - Name: John Smith; Region: MW; ID: 1 Entry 2 - Name: John Smith; Region: S; ID: 1 Entry 3 - Name: Jane Doe; Region: NULL; ID: 2 Entry 4 - Name: Jack Black; Region: N; ID: 3 Entry 6 - Name: Jack Black; Region: MW; ID: 3 Entry 7 - Name: Joe Don; Region: NE; ID: 4 I want to transform the list to below by combining duplicate regions together for the same ID. Therefore, the final list should have only 4 distinct elements with the regions combined. So the output should look like this:- Entry 0 - Name: John Smith; Region: N,MW,S; ID: 1 Entry 1 - Name: Jane Doe; Region: NULL; ID: 2 Entry 2 - Name: Jack Black; Region: N,MW; ID: 3 Entry 3 - Name: Joe Don; Region: NE; ID: 4 What are your thoughts on the optimal way to solve this? I am not looking for actual code but ideas or tips to go about the best way to get it done. Thanks for your time!!!

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• Finding if a Binary Tree is a Binary Search Tree

  - by dharam

  Today I had an interview where I was asked to write a program which takes a Binary Tree and returns true if it is also a Binary Search Tree otherwise false. My Approach1: Perform an inroder traversal and store the elements in O(n) time. Now scan through the array/list of elements and check if element at ith index is greater than element at (i+1)th index. If such a condition is encountered, return false and break out of the loop. (This takes O(n) time). At the end return true. But this gentleman wanted me to provide an efficient solution. I tried but I was unsuccessfult, because to find if it is a BST I have to check each node. Moreover he was pointing me to think over recusrion. My Approach 2: A BT is a BST if for any node N N-left is < N and N-right N , and the INorder successor of left node of N is less than N and the inorder successor of right node of N is greater than N and the left and right subtrees are BSTs. But this is going to be complicated and running time doesn't seem to be good. Please help if you know any optimal solution. Thanks.

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• What tools/techniques can benefit a solo developer?

  - by Michael Runyon

  Hello, I am a solo developer, working in a very small web development firm. There is occasional support for development from contractors, but for the most part, if code is written in the office, I am writing it. Many of the articles and such on here talk extensively about the tools and techniques used for collaboration of developers in teams, but that is a non-issue with me, as there is no one to (technically) collaborate with. Yet, I feel that in many ways, there are things that could be adjusted for efficiency. Our small office doesn't participate in many of the meetings/team constructions that most of the techniques rely heavily upon....we mostly just walk around and talk to one another when something is needed. This works great for all of the Just-In-Time, 15 minute fix stuff that probably populates 50% of my day, but I am also constantly working on major projects that require my total concentration, and between a flurry of tiny fixes, and being the primary admin on the 4-6 servers that we own, I find it almost impossible to get real, heavy lifting done. What suggestions can you some of you offer to help me/us become more productive/efficient, without adopting all of the corporate/teamwork practices that we are trying desperately to avoid? At what cost for efficiency is our total relaxation?

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• Cloning and renaming form elements with jQuery

  - by Micor

  I am looking for an effective way to either clone/rename or re-create address fields to offer ability to submit multiple addresses on the same page. So with form example like this: <div id="addresses"> <div class="address"> <input type="text" name="address[0].street"> <input type="text" name="address[0].city"> <input type="text" name="address[0].zip"> <input type="text" name="address[0].state"> </div> </div> <a href="" id="add_address">Add address form</a> From what I can understand there are two options to do that: Recreate the form field by field and increment the index which is kind of verbose: var index = $(".address").length; $('<`input`>').attr({ name: 'address[' + index + '].street', type: 'text' }).appendTo(...); $('<`input`>').attr({ name: 'address[' + index + '].city', type: 'text' }).appendTo(...); $('<`input`>').attr({ name: 'address[' + index + '].zip', type: 'text' }).appendTo(...); $('<`input`>').attr({ name: 'address[' + index + '].state', type: 'text' }).appendTo(...); Clone Existing layer and replace the name in the clone: $("div.address").clone().appendTo($("#addresses")); Which one do you recommend using in terms of being more efficient and if its #2 can you please suggest how I would go about search and replacing all occurrences of [0] with [1] ([n]). Thank you.

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• maintaining a large list in python

  - by Oren

  I need to maintain a large list of python pickleable objects that will quickly execute the following algorithm: The list will have 4 pointers and can: Read\Write each of the 4 pointed nodes Insert new nodes before the pointed nodes Increase a pointer by 1 Pop nodes from the beginning of the list (without overlapping the pointers) Add nodes at the end of the list The list can be very large (300-400 MB), so it shouldnt be contained in the RAM. The nodes are small (100-200 bytes) but can contain various types of data. The most efficient way it can be done, in my opinion, is to implement some paging-mechanism. On the harddrive there will be some database of a linked-list of pages where in every moment up to 5 of them are loaded in the memory. On insertion, if some max-page-size was reached, the page will be splitted to 2 small pages, and on pointer increment, if a pointer is increased beyond its loaded page, the following page will be loaded instead. This is a good solution, but I don't have the time to write it, especially if I want to make it generic and implement all the python-list features. Using a SQL tables is not good either, since I'll need to implement a complex index-key mechanism. I tried ZODB and zc.blist, which implement a BTree based list that can be stored in a ZODB database file, but I don't know how to configure it so the above features will run in reasonable time. I don't need all the multi-threading\transactioning features. No one else will touch the database-file except for my single-thread program. Can anyone explain me how to configure the ZODB\zc.blist so the above features will run fast, or show me a different large-list implementation?

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• Any way for a class to prevent outside code from declaring variables of its type?

  - by supercat

  Is it possible for a class of exposing a type for function returns, without allowing users of that class to create variables of that type? A couple usage scenarios: A Fluent interface on a large class; a statement like "foo=bar.WithX(5).WithY(9).WithZ(19);" would be inefficient if it had to create three new instances of the class, but could be much more efficient if the WithX could create one instance, and the other statements could simply use it. A class may wish to support a statement like "foo[19].x = 9;" even when foo itself isn't an array, and does not hold the data in class instances that can be exposed to the public; one way to do that is to have foo[19] return a struct which holds a reference to 'foo' and the value '19', and has a member property 'x' which could call "foo.SetXValue(19, 9);" Such a struct could have a conversion operator to convert itself to the "apparent" type of foo[19]. In both of these scenarios, storing the value returned by a method or property into a variable and then using it more than once would cause strange behavior. It would be desirable if the designer of the class exposing such methods or properties could ensure that callers wouldn't be able to use them more than once. Is there any practical way to accomplish that?

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• How to implement Priority Queues in Python?

  - by dragosrsupercool

  Sorry for such a silly question but Python docs are confusing.. . Link 1: Queue Implementation http://docs.python.org/library/queue.html It says thats Queue has a contruct for priority queue. But I could not find how to implement it. class Queue.PriorityQueue(maxsize=0) Link 2: Heap Implementation http://docs.python.org/library/heapq.html Here they says that we can implement priority queues indirectly using heapq pq = [] # list of entries arranged in a heap entry_finder = {} # mapping of tasks to entries REMOVED = '<removed-task>' # placeholder for a removed task counter = itertools.count() # unique sequence count def add_task(task, priority=0): 'Add a new task or update the priority of an existing task' if task in entry_finder: remove_task(task) count = next(counter) entry = [priority, count, task] entry_finder[task] = entry heappush(pq, entry) def remove_task(task): 'Mark an existing task as REMOVED. Raise KeyError if not found.' entry = entry_finder.pop(task) entry[-1] = REMOVED def pop_task(): 'Remove and return the lowest priority task. Raise KeyError if empty.' while pq: priority, count, task = heappop(pq) if task is not REMOVED: del entry_finder[task] return task raise KeyError('pop from an empty priority queue' Which is the most efficient priority queue implementation in python? And how to implement it?

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