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  • Getting a CFG form the CFL

    - by Kristian
    Can Any One explain this Language how we converted to CFG Give a CFG for the CFL: {ai bj ck | i ? j or j ? k } //ai mean a^i I have the answer but I need an explaination (Step By Step) The answer : S --> S1|S2 S1 --> A Eab|Eab B|S1 c A --> a|aA B--> b|bB Eab --> Q|a Eab b S2 --> Eac C|A Eac C --> c|cC Eac --> Q|B|a Eac c

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  • Which is the "best" data access framework/approach for C# and .NET?

    - by Frans
    (EDIT: I made it a community wiki as it is more suited to a collaborative format.) There are a plethora of ways to access SQL Server and other databases from .NET. All have their pros and cons and it will never be a simple question of which is "best" - the answer will always be "it depends". However, I am looking for a comparison at a high level of the different approaches and frameworks in the context of different levels of systems. For example, I would imagine that for a quick-and-dirty Web 2.0 application the answer would be very different from an in-house Enterprise-level CRUD application. I am aware that there are numerous questions on Stack Overflow dealing with subsets of this question, but I think it would be useful to try to build a summary comparison. I will endeavour to update the question with corrections and clarifications as we go. So far, this is my understanding at a high level - but I am sure it is wrong... I am primarily focusing on the Microsoft approaches to keep this focused. ADO.NET Entity Framework Database agnostic Good because it allows swapping backends in and out Bad because it can hit performance and database vendors are not too happy about it Seems to be MS's preferred route for the future Complicated to learn (though, see 267357) It is accessed through LINQ to Entities so provides ORM, thus allowing abstraction in your code LINQ to SQL Uncertain future (see Is LINQ to SQL truly dead?) Easy to learn (?) Only works with MS SQL Server See also Pros and cons of LINQ "Standard" ADO.NET No ORM No abstraction so you are back to "roll your own" and play with dynamically generated SQL Direct access, allows potentially better performance This ties in to the age-old debate of whether to focus on objects or relational data, to which the answer of course is "it depends on where the bulk of the work is" and since that is an unanswerable question hopefully we don't have to go in to that too much. IMHO, if your application is primarily manipulating large amounts of data, it does not make sense to abstract it too much into objects in the front-end code, you are better off using stored procedures and dynamic SQL to do as much of the work as possible on the back-end. Whereas, if you primarily have user interaction which causes database interaction at the level of tens or hundreds of rows then ORM makes complete sense. So, I guess my argument for good old-fashioned ADO.NET would be in the case where you manipulate and modify large datasets, in which case you will benefit from the direct access to the backend. Another case, of course, is where you have to access a legacy database that is already guarded by stored procedures. ASP.NET Data Source Controls Are these something altogether different or just a layer over standard ADO.NET? - Would you really use these if you had a DAL or if you implemented LINQ or Entities? NHibernate Seems to be a very powerful and powerful ORM? Open source Some other relevant links; NHibernate or LINQ to SQL Entity Framework vs LINQ to SQL

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  • Sql Server performance

    - by Jose
    I know that I can't get a specific answer to my question, but I would like to know if I can find the tools to get to my answer. Ok we have a Sql Server 2008 database that for the last 4 days has had moments where for 5-20 minutes becomes unresponsive for specific queries. e.g. The following queries run in different query windows simultaneously have the following results SELECT * FROM Assignment --hangs indefinitely SELECT * FROM Invoice -- works fine Many of the tables have non-clustered indexes to help speed up SELECTs Here's what I know: 1) The same query will either hang indefinitely or run normally. 2) In Activity Monitor in the processes tab there are normally around 80-100 processes running I think that what's happening is 1) A user updates a table 2) This causes one or more indexes to get updated 3) Another user issues a select while the index is updating Is there a way I can figure out why at a specific moment in time SQL Server is being unresponsive for a specific query?

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  • Sqlite database entries pass to array list?

    - by Rjay Guillermo Baltazar
    This is my code in getting the question into SQLite Database . I want to pass the questions into array list ? is it possible to my code ? Thanks for your help . public String getquestions() { // TODO Auto-generated method stub String[] sqlSelect = { "0 _id", "question", "answer" }; String sqlTables = "mytables"; SQLiteDatabase db = getWritableDatabase(); SQLiteQueryBuilder qb = new SQLiteQueryBuilder(); qb.setTables(sqlTables); String result = ""; c = qb.query(db, sqlSelect, null, null, null, null, null); int id = c.getColumnIndex(ID); int question = c.getColumnIndex(ROW1); int answer = c.getColumnIndex(ROW2); c.moveToFirst(); result = result + c.getString(question) + c.getString(count); return result; }

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  • How to Have a Bundled Configurable Product in Magento ??

    - by Calua
    Hi everybody, I've been searching about this topic on Magento forum and Google but can't find a definite answer for the question. Hope I find it here. Is it possible to have a bundled configurable products in Magento? Take for example I want to sell a set of t-shirt and short on a product page where the customer can choose the number of quantity, the color and the size for the t-shirt and short respectively. Maybe like this : T-Shirt [A configurable Product] Color : [combobox to select color] Size : [combobox to select Size] Qty : [input to enter the qty] Short [Another configurable Product] Color : [combobox to select color] Size : [combobox to select Size] Qty : [input to enter the qty] [Add to Cart Button] Any help and answer will be much appreciated. Thanks!

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  • Codesample with bufferoverflow (gets method). Why does it not behave as expected?

    - by citronas
    This an extract from an c program that should demonstrate a bufferoverflow. void foo() { char arr[8]; printf(" enter bla bla bla"); gets(arr); printf(" you entered %s\n", arr); } The question was "How many input chars can a user maximal enter without a creating a buffer overflow" My initial answer was 8, because the char-array is 8 bytes long. Although I was pretty certain my answer was correct, I tried a higher amount of chars, and found that the limit of chars that I can enter, before I get a segmentation fault is 11. (Im running this on A VirtualBox Ubuntu) So my question is: Why is it possible to enter 11 chars into that 8 byte array?

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  • ArgumentException was unhandled Application.run

    - by user369758
    Hi I've been through many sites and can't seem to find an answer. I modified a view that was connected to a Datagridview connected through a tableadapter on a C# Winforms app and in order to "reconnect" I had to delete the tableadapter and reconnect it. This was to get rid of an error regarding Unique contstraints. So I fixed that and now the application launches but when I click on the tab that that grid is on I get: System.ArgumentException was unhandled Message="Cannot bind to the property or column Id on the DataSource.\r\nParameter name: dataMember" Source="System.Windows.Forms" ParamName="dataMember" StackTrace: at System.Windows.Forms.BindToObject.CheckBinding() at System.Windows.Forms.BindToObject.SetBindingManagerBase(BindingManagerBase lManager)......... I can't seem to find an answer to this problem. Can someone help me? Thanks

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  • Is there anyway to write the following as a C++ macro?

    - by anon
    my_macro << 1 << "hello world" << blah->getValue() << std::endl; should expand into: std::ostringstream oss; oss << 1 << "hello world" << blah->getValue() << std::endl; ThreadSafeLogging(oss.str()); Thanks! EDIT: the accepted answer is awesome. Can we upvote 8 more times and win this responder a badge? (The answer only needs 6 more upvotes). 4 more votes to go from 21 to 25. 3 more. :-) Victory. :-)

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  • In python, is there anyway to have a variable be a different random number everytime?

    - by woah113
    Basically I have this: import random variable1 = random.randint(13, 19) And basically what that does is assign variable1 a random number between 13 and 19. Great. But, what I want it to do is assign a different random number between 13 and 19 to that variable every time it is called. Is there anyway I can do this? If I'm not being clear enough here's an example: import random variable1 = random.randint(13, 19) print(variable1) print(variable1) print(variable1) And the output I want would look something like this: ./script.py 15 19 13 So yeah, anyway I could do this in python? (More specifically python3. but the answer would probably be similar to a python2 answer)

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  • Anova test in the loop and outputing the p-value in separate column

    - by Juanhijuan
    Once again I'm trying to get an answer. I am already stuck for like 5h with that so that's why I keep trying to get an answer. That's my data: id Sequence variable value 75 AAAAGAAAVANQGKK BiotinControl1_2 3893050.50 192 AAAAGAAAVANQGKK BiotinControl1_2 900604.61 3770 AAFTKLDQVWGSE BiotinControl1_2 90008.14 The code which I am trying to use to calculate the p-value: My Code: tbl_anv <- tbl_all_onlyK[,c("id", "BiotinControl1_2", "BiotinControl2", "BiotinControl3", "BiotinTreatment1_2", "BiotinTreatment2", "BiotinTreatment3", "Sequence")] tbl_reo <- melt(tbl_anv, measure.vars=2:7) set.seed(1) vars <- c("id", "BiotinControl1_2", "BiotinControl2", "BiotinControl3", "BiotinTreatment1_2", "BiotinTreatment2", "BiotinTreatment3", "Sequence") tbl_reo <- as.data.frame(tbl_reo) by(tbl_reo,tbl_reo$Sequence,function(x){ anova(lm(value ~ variable, data = x))$"Pr(>F)"[1] }) An error ocurs: There were 50 or more warnings (use warnings() to see the first 50) Anyway, how can I do that and export the p-value in the separate column. That's what I tried to do on my own: aov_test <- by(tbl_reo,tbl_reo$Sequence,function(x){ anova(lm(value ~ variable, data = x))$"Pr(>F)"[1] }) tbl_reo[,5] <- aov.test[[1]]$'Pr(>F)'[1]

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  • Abstracting the adding of click events to elements selected by class using jQuery

    - by baroquedub
    I'm slowly getting up to speed with jQuery and am starting to want to abstract my code. I'm running into problems trying to define click events at page load. In the code below, I'm trying to run through each div with the 'block' class and add events to some of its child elements by selecting them by class: <script language="javascript" type="text/javascript"> $(document).ready(function (){ $('HTML').addClass('JS'); // if JS enabled, hide answers $(".block").each(function() { problem = $(this).children('.problem'); button = $(this).children('.showButton'); problem.data('currentState', 'off'); button.click(function() { if ((problem.data('currentState')) == 'off'){ button.children('.btn').html('Hide'); problem.data('currentState', 'on'); problem.fadeIn('slow'); } else if ((problem.data('currentState')) == 'on'){ button.children('.btn').html('Solve'); problem.data('currentState', 'off'); problem.fadeOut('fast'); } return false; }); }); }); </script> <style media="all" type="text/css"> .JS div.problem{display:none;} </style> <div class="block"> <div class="showButton"> <a href="#" title="Show solution" class="btn">Solve</a> </div> <div class="problem"> <p>Answer 1</p> </div> </div> <div class="block"> <div class="showButton"> <a href="#" title="Show solution" class="btn">Solve</a> </div> <div class="problem"> <p>Answer 2</p> </div> </div> Unfortunately using this, only the last of the divs' button actually works. The event is not 'localised' (if that's the right word for it?) i.e. the event is only applied to the last $(".block") in the each method. So I have to laboriously add ids for each element and define my click events one by one. Surely there's a better way! Can anyone tell me what I'm doing wrong? And how I can get rid of the need for those IDs (I want this to work on dynamically generated pages where I might not know how many 'blocks' there are...) <script language="javascript" type="text/javascript"> $(document).ready(function (){ $('HTML').addClass('JS'); // if JS enabled, hide answers // Preferred version DOESN'T' WORK // So have to add ids to each element and laboriously set-up each one in turn... $('#problem1').data('currentState', 'off'); $('#showButton1').click(function() { if (($('#problem1').data('currentState')) == 'off'){ $('#showButton1 > a').html('Hide'); $('#problem1').data('currentState', 'on'); $('#problem1').fadeIn('slow'); } else if (($('#problem1').data('currentState')) == 'on'){ $('#showButton1 > a').html('Solve'); $('#problem1').data('currentState', 'off'); $('#problem1').fadeOut('fast'); } return false; }); $('#problem2').data('currentState', 'off'); $('#showButton2').click(function() { if (($('#problem2').data('currentState')) == 'off'){ $('#showButton2 > a').html('Hide'); $('#problem2').data('currentState', 'on'); $('#problem2').fadeIn('slow'); } else if (($('#problem2').data('currentState')) == 'on'){ $('#showButton2 > a').html('Solve'); $('#problem2').data('currentState', 'off'); $('#problem2').fadeOut('fast'); } return false; }); }); </script> <style media="all" type="text/css"> .JS div.problem{display:none;} </style> <div class="block"> <div class="showButton" id="showButton1"> <a href="#" title="Show solution" class="btn">Solve</a> </div> <div class="problem" id="problem1"> <p>Answer 1</p> </div> </div> <div class="block"> <div class="showButton" id="showButton2"> <a href="#" title="Show solution" class="btn">Solve</a> </div> <div class="problem" id="problem2"> <p>Answer 2</p> </div> </div>

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  • How to dump STDIN to a file, using C++ STL?

    - by Jimm Chen
    HHello all, this is a straight forward question, but not a straight forward answer can be found by just Googling today. Hope someone can show me a concise answer before I dig into those thick C++ books and finally find the solution out. Thank you. I'm writing this program so to make a workaround in this issue: Why do I get 'Bad file descriptor' when trying sys.stdin.read() in subversion pre-revprop-change py script? Note: Content from STDIN may be arbitrary binary data. Please use C++ STL functions, iostream, ifstream etc . If the file creation/writing failed, I'd like to catch the exception to know the case.

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  • Planning a skillset for a fallback career [closed]

    - by Davy Kavanagh
    I'm not too certain this is a SO question, but I didn't think it belonged in meta either. Long story short, I am bioinformatics researcher. I like to code, it's my favourite part of the job. I have been thinking for a while that if academia is not kind to me, I might seek a career in software development. My current contract is for three years and I would like to spend some time over the next 3 three years learning and practicing software development as possible. Python seems like a popular language and it what I mostly use to do things for me, but I am also in heavy use of R. So my main question is: Are python and R good things to be learning with a sotfware dev goal in mind, and if so, is there any particular type of programming or software that might be useful to have experience with. Hard questions to answer I know, but I thought I would get the answer from people who are in the know. Cheers, Davy.

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  • Jetty servlet respons to Ajax always empty

    - by chris
    Hi I try to run a java server on Jetty which should respond to an ajax call. Unfortunately the response seems to be empty when I call it with ajax. When I call http://localhost:8081/?id=something I get an answer. The Java Server: public class Answer extends AbstractHandler { public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String id = request.getParameter("id"); response.setContentType("text/xml"); response.setHeader("Cache-Control", "no-cache"); response.setContentLength(19+id.length()); response.setStatus(HttpServletResponse.SC_OK); response.getWriter().write("<message>"+id+"</message>"); //response.setContentType("text/html;charset=utf-8"); response.flushBuffer(); baseRequest.setHandled(true); } public static void main(String[] args) throws Exception { Server server = new Server(8081); server.setHandler(new Answer()); server.start(); server.join(); } } The js and html: <html> <head> <script> var req; function validate() { var idField = document.getElementById("userid"); var url = "validate?id=" + encodeURIComponent(idField.value); if (typeof XMLHttpRequest != "undefined") { req = new XMLHttpRequest(); } else if (window.ActiveXObject) { req = new ActiveXObject("Microsoft.XMLHTTP"); } req.open("GET", "http://localhost:8081?id=fd", true); req.onreadystatechange = callback; req.send(null); } function callback() { if (req.readyState == 4) { if (req.status == 200) { var message = req.responseXML.getElementsByTagName("message")[0]; document.getElementById("userid").innerHTML = "message.childNodes[0].nodeValue"; } } } </script> </head> <body onload="validate('foobar')"> <div id="userid">hannak</div> </body> </html> I'm actually don't know what I'm doing wrong here. Maybe someone has a good idea. greetings chris

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  • How are python pages coded and what can the language be compared to? [closed]

    - by avon_verma
    I have a few questions about python I've seen many pages like these on Google http://mail.google.com/support/bin/answer.py?answer=6583 https://www.google.com/adsense/support/bin/topic.py?topic=13488 ...that have .py extensions. 1: Are pages like these built on pure python code, but printing out html like print "<div etc..." or like the typical asp,jsp,php type of pages with html pages and embedded python code like: <html> <% some python code %> </html> 2: What is python mainly used for making? windows apps or web or .. ? 3: Are ruby and perl also similar to python?

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  • How do I disable maven build when using Maven 2.0 integration for eclipse?

    - by Stein G. Strindhaug
    How do I stop the "Maven 2.0 integration" plugin from running maven build, while keeping "build automatically" checked? I'm pretty sure it used to be some check box to disable maven build before, but after upgrading Ubuntu; eclipse seems to have been updated in the process, and now I cannot find any way to turn off the maven build. The maven build takes literally minutes (about 5 minutes or so), while just running java build used to finish in seconds. Is it no longer possible to disable it or have they just hidden it well? If it's not possible, will eclipse be able to compile my maven project without the plugin? (Trying to google for a solution the closes I got to an answer was several archives of this old post where the answer essentially were "You should be able to disable Maven builder in project preferences..." which doesn't really help because I cannot find any on/off settings there)

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  • Do Managers in Python Multiprocessing module lock the shared data?

    - by AnonProcess
    This Question has been asked before: http://stackoverflow.com/questions/2936626/how-to-share-a-dictionary-between-multiple-processes-in-python-without-locking However I have several doubts regarding the program given in the answer: The issue is that the following step isn't atomic d['blah'] += 1 Even with locking the answer provided in that question would lead to random results. Since Process 1 read value of d['blah'] saves it on the stack increments it and again writes it. In Between a Process 2 can read the d['blah'] as well. Locking means that while d['blah'] is being written or read no other process can access it. Can someone clarify my doubts?

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  • What are the exact versions of stuff you have to install in order to be able to step-debug a Scala p

    - by Alex R
    How do YOU debug a Scala program? I mean YOU as in the person posting the Answer :) Please answer only from personal experience, not from stuff you've heard or read on the Internet. You should not believe everything you read on the Internet, especially tales of complex open-source software configurations that actually work :-) The are many Java tools which claim to support Scala in some way or another, but I have so far struck out in trying to get any one of them to actually let me set a breakpoint in Scala code and step through it. These are big, major open-source IDEs I'm talking about here. The main problem in getting a debugger to work seems to be the "version hell" with fast-changing IDEs, Plug-Ins, JDKs, and the Scala language itself. Hence, the more detailed re-statement of the question is appropriate: What is the exact version number of the IDE, Plug-In, JDK, Scala, and even Operating System, that you are successfully using? My question is related to this one, but wider in scope: http://stackoverflow.com/questions/2272705/how-to-debug-scala-code-when-outside-of-an-ide Thanks

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  • When are C++ macros beneficial?

    - by Motti
    The C preprocessor is justifiably feared and shunned by the C++ community. In-lined functions, consts and templates are usually a safer and superior alternative to a #define. The following macro: #define SUCCEEDED(hr) ((HRESULT)(hr) >= 0) is in no way superior to the type safe: inline bool succeeded(int hr) { return hr >= 0; } But macros do have their place, please list the uses you find for macros that you can't do without the preprocessor. Please put each use-cases in a seperate answer so it can be voted up and if you know of how to achieve one of the answers without the preprosessor point out how in that answer's comments.

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  • PHP imap_search not detecting all messages in gmail inbox

    - by Steve
    When I run a very simple imap_search on my GMail inbox, the search returns less messages than it should. Here is the script that anyone with a GMail account can run. $host = '{imap.gmail.com:993/imap/ssl}'; $user = 'foo'; $pass = 'bar'; $imapStream = imap_open($host,$user,$pass) or die(imap_last_error()); $messages = imap_search($imapStream,"ALL"); echo count($messages); imap_close($imapStream); This returns 39 messages. But, I've got 100 messages in my inbox, some in conversations, some forwarded from another account (SquirrelMail, FWIW). Can anyone duplicate these results, and/or tell me what's going on? Other server strings I've tried, all returning the same results: {imap.gmail.com:993/imap/ssl/novalidate-cert} {imap.gmail.com:993/imap/ssl/novalidate-cert}INBOX {imap.gmail.com:993/imap/ssl}INBOX GMail's IMAP feature support: http://mail.google.com/support/bin/answer.py?hl=en&answer=78761

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  • Counting number of GC cleanups on an object

    - by tsps
    How do I keep a count of the number of times that objects of a specific class (type?) are getting disposed in the lifetime of my application. Imagine I have a class A, now, I want to count how many times the objects of A get collected by the GC. I hope I am phrasing this right because I was asked this in an interview today and the answer I gave did not satisfy the interviewer. And this is what I imagine he was trying to ask. What I said was that one could keep a static field called count in the class A and increment it in the Finalize() call of that object. The answer he was expecting was something called a static block. I've never heard of this in .NET/C#. Can someone explain what's this static block?

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  • XSLT Similar functionality to SQL "WHERE LIKE"

    - by Fishcake
    I have the following XML <Answer> <Label>FCVCMileage</Label> <Value>3258</Value> <Iteration>0</Iteration> <DataType>NUMBER</DataType> </Answer> And need to get the Value underneath the Mileage label. However the 4 letter prefix to Mileage could be any 1 of 8 different prefixes. I know I could find the value by testing for every combination using xsl:if or xsl:choose but is there a more elegant way that would work similar to the following SQL and also wouldn't need changes to code being made if other prefixes were added. WHERE label LIKE '%Mileage' NB. There will only ever be 1 label element containing the word Mileage Cheers!

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  • MySQL Import Database Error because of Extended Inserts

    - by Castgame
    Hello all, I'm importing a 400MB(uncompressed) MySQL database. I'm using BIGDUMP, and I am getting this error: Stopped at the line 387. At this place the current query includes more than 300 dump lines. That can happen if your dump file was created by some tool which doesn't place a semicolon followed by a linebreak at the end of each query, or if your dump contains extended inserts. Please read the BigDump FAQs for more infos. I believe the file does contain Extended Inserts, however I have no way to regenerate the database as it has been deleted from the old server. How can I import this database or convert it to be imported? Thanks for any help. Best Nick EDIT: It appears the only viable answer is to separate the extended inserts, but I still need help figuring out how to split the file as the answer below suggests. Please help. Thank you.

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