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• Perl, efficient parsing of csv file

  - by Mike

  I'm working on a project that involves parsing a large csv formatted file in Perl and am looking to make things more efficient. My approach has been to split() the file by lines first, and then split() each line again by commas to get the fields. But this suboptimal since at least two passes on the data are required. (once to split by lines, then once again for each line). This is a very large file, so cutting processing in half would be a significant improvement to the entire application. My question is, what is the most time efficient means of parsing a large CSV file using only built in tools? note: Each line has a varying number of tokens, so we can't just ignore lines and split by commas only. Also we can assume fields will contain only alphanumeric ascii data (no special characters or other tricks). Also, i don't want to get into parallel processing, although that might work effectively.

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• Working with multiple input and output files in Python

  - by Morlock

  I need to open multiple files (2 input and 2 output files), do complex manipulations on the lines from input files and then append results at the end of 2 output files. I am currently using the following approach: in_1 = open(input_1) in_2 = open(input_2) out_1 = open(output_1, "w") out_2 = open(output_2, "w") # Read one line from each 'in_' file # Do many operations on the DNA sequences included in the input files # Append one line to each 'out_' file in_1.close() in_2.close() out_1.close() out_2.close() The files are huge (each potentially approaching 1Go, that is why I am reading through these input files one at a time. I am guessing that this is not a very Pythonic way to do things. :) Would using the following form good? with open("file1") as f1: with open("file2") as f2: # etc. If yes, could I do it while avoiding the highly indented code that would result? Thanks for the insights!

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• Find out 20th, 30th, nth prime number. (I'm getting 20th but not 30th?) [Python]

  - by gsin

  The question is to find the 1000th prime number. I wrote the following python code for this. The problem is, I get the right answer for the 10th , 20th prime but after that each increment of 10 leaves me one off the mark. I can't catch the bug here :( count=1 #to keep count of prime numbers primes=() #tuple to hold primes candidate=3 #variable to test for primes while count<20: for x in range(2,candidate): if candidate%x==0: candidate=candidate+2 else : pass primes=primes+(candidate,) candidate=candidate+2 count=count+1 print primes print "20th prime is ", primes[-1] In case you're wondering, count is initialised as 1 because I am not testing for 2 as a prime number(I'm starting from 3) and candidate is being incremented by 2 because only odd numbers can be prime numbers. I know there are other ways of solving this problem, such as the prime number theorem but I wanna know what's wrong with this approach. Also if there are any optimisations you have in mind, please suggest. Thank You

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• Dynamically display properties of a control

  - by Ram

  Hi, To access the properties of windows controls in multi threaded application, I have modified my code as specified here solution. Although for calling the "SetControlValueMethod" I also need to pass the type of control and its specific property as text. I am looking for more convenient approach for callingvoid SetControlValueMethod(Control controlType,string propertyName, object value) Can I have all controls as a enum as first parameter. can I have properties of the selected control appear for second parameter, I don't want to type property name there. Can I have them appearing like enum for selected control?

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• ZipArchive php Class - Is it built-in to PHP?

  - by SoLoGHoST

  Ok, just wondering on the versions of PHP that this class is built into. And if they are built into all platforms (OS's). I'm wanting an approach to search through a zip file and place files using file_put_contents in different filepaths within the webroot. In any case, I'm familiar with how to do this with the ZipArchive class, but I'm wondering if using this class would be a good solution and support MOST, if not ALL servers?? I mean, I'd rather not use a method that requires the Server to have it installed. I'm looking for a solution to this that will support at least MOST servers without having to install the class... Thanks :) Also, I'd like to support opening tar.gz and/or .tgz files if possible, but I don't think the ZipArchive class supports this, but perhaps a different built-in php class does??

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• Given two lines on a plane, how to find integer points closest to their intersection?

  - by Lukasz Lew

  I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach. Update: You can assume that the 8 numbers on input are 32-bit signed integers. But you cannot assume that the solution will be 32 bit.

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• Migrating from Forms to WPF

  - by Jason Williams

  We're considering migrating a WinForms app to WPF, but are just starting on the WPF learning curve now that 4.0 is out. What I'd like to do is migrate our application commands (cut, copy, paste, etc) to a WPF-like command-binding system, while still running as a WinForms app - but in such a way as to make the migration easy when we go ahead with WPF. The ideal approach would be to implement our commands using the WPF command interfaces, classes and events directly, and simply hooking the WinForms events up to them with our own dispatcher. Has anyone tried something like this or know if it might be possible?

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• Mapping one to one foreign key relationships in Entity Framework 4.0?

  - by John K.

  Hello all, I'm sure I'm missing something very simple, but let's say I have two entities, Employee and EmployeeType. Employee type would contain values like 'Full time', 'Contractor', 'Intern', etc. An Employee entity would contain one, and only one EmployeeType value. So I am designing a new .edmx model using the Model-First approach and generating my actual sql server data schema from the model. I want to add an integer type foreign key id into my Employee entity, EmployeeTypeId, which will map to the primary key of the EmployeeType entity. So I've gone ahead and done that in my Employee entity. Where I'm stuck is how, though the Entity Framework designer, to enforce the 1:1 referential constraint on that EmployeeTypeId property? Or does the EF handle that automatically behind the scenes? thanks in advance, John

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• How to store account-specific information in ASP.NET MVC 2

  - by PR_

  I have an ASP.NET MVC 2 web application. There are two tables like "FIRST_KIND_OF_USERS" and "SECOND_KIND_OF_USERS". Both are mapped to the default aspnet_users table via UserId column. Each of them has it's own integer primary key column like "FirstKindOfUsersId". When a user is trying to add some data to the database, for instance, "Create a new Task" I would like to add a new row in Tasks table with "FirstKindOfUsersId" value. Where should I store or get this value? At the moment I have these possible solutions: Get "FirstKindOfUsersId" value by User.Identity.Name each time; Use SESSION[] for storing these values (Where and when should I save these ones?) Use FormsAuthenticationTicket and create own custom IIdentity class. (http://stackoverflow.com/questions/1064271/asp-net-mvc-set-custom-iidentity-or-iprincipal) Which approach is better? And if I pick the 3rd one, how to save the necessary data property and at which stage?

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• algorithm advice for finding maximum items within a time period

  - by darren

  Hi everyone. I have a database schema that is similar to the following: | User | Event | Date |--------|---------------|------ | 111 | Walked dog | 2009-10-1 | 222 | Walked dog | 2009-10-2 | 333 | Fed Fish | 2009-10-5 | 222 | Did Laundry | 2009-10-6 | 111 | Fed Fish | 2009-10-7 | 111 | Walked dog | 2009-10-18 | 222 | Walked dog | 2009-10-19 | 111 | Fed Fish | 2009-10-21 I would like to produce a query that returns the maximum number of times a user performs some action within a time period. For example, given a time period of 5 days, what is the maximum number of times user 111 walked the dog? The most obvious solution would be to start at some zero point and move forward each day, summing up 5 day periods along the way, then taking the maximum total out of all the 5 day windows. the approach seems incredibly costly however. I would appreciate any suggestions you may have.

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• How to convert a MSSQL database (including procedures, functions and triggers) to a firebird databas

  - by user193655

  I am considering migrating to Firebird. To have a "quick start" approach I downloaded the trial of a conversion tool (DBConvert) and tried it. I just picked up a random tool, this tool doesn't convert procedures, functions and triggers (I don't think it is a limit of the trial since there is not an explicit reference to sp, sf and triggers in the link above). Anyway by trying that tool I had the message: "The DB cannot be converted succesfully because some FK names are too long." This is because in some tables I have FK whose description is 32 chars. Is this a real firebird limit or it is possible to overcome it somehow (of course renaming the FK is an extreme option because it is extra work)? Anyway how to convert a MS SQL DB fully to FIREBIRD? Is there a valid tool? Did someone succed in a conversion of non trivial databases?

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• How can I implement a "wizard" style page using JQuery?

  - by Mark Brittingham

  I am implementing a questionnaire on the web and I'd like for each block of questions to have its own "page" so the user doesn't have to scroll. However, page loads have two problems: a) they take time (and have a noticeable flicker/refresh) and b) such an approach would force me to do a data table insert plus multiple updates (or store it all in my session). How can I use JQuery to let the user page through the questionnaire on the client side, answering questions as he goes? I'll then be able to handle the data store when all the answers are submitted at the end. One other thing...is there a way to make sure that the session doesn't time out if the user takes awhile?

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• What signing method to use for public open-source projects?

  - by Irchi

  I'm publishing an open-source library on CodePlex, and want the dll files to have strong names so that they can be added to GAC. What's the best option for signing? Should I use SNK? If so, everyone have access to the key. I don't have a problem with everyone having access, but is it a good approach? Should I use PFX? If so, does it mean that other people downloading the source code are not able to build the solution? What I like to do is that I am the only one person to have access to the key, so that the signed assemblies also have a level of authenticity, but meanwhile don't prevent other developers to download, build, or change the source code for themselves, and be able to post changes for the main project.

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• iPhone / NSArray : How do I format a text file to be read in using arrayWithContentsOfFile

  - by nickthedude

  I have several large word lists and I had been loading them in place in the code as follows: NSArray *dict3 = [[NSArray alloc] initWithObjects:@"abled",@"about",@"above",@"absurd",@"absurdity", ... but now it is actually causing an exc_bad_access error weirdly, i know it seems implausible but for some reason IT IS causing it. (trust me on this I just spend the better part of a day debugging this crap) Anyway, I'm looking to get these humongous lines of code out of my files but I'm not sure what the best approach is. I guess I could do a plist but I need to figure out how to automate the process. it be easiest if I could just use the text files I've been compiling so if anyone knows how I can format the text file so that the myArray = [NSArray arrayWithContentsOfFile: @"myTextFile.txt"]; will be read in correctly as one word per element in the array it would really be appreciated. Thanks, Nick

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• How to efficiently handle Where and OrderBy clauses

  - by Goran

  My business layer passes all the required information to UI layer. From what I have read, in general, best practice is to send fetched data to UI layer, and to avoid passing queries like ObjectQuery. My problem with this approach is next: If I am to make a flexible business layer, then I should allow UI to sort the data anyway it requires. Fetching sorted data from database, and then resorting them in UI is kind of bad practice for me, so the only way is to somehow So what are my options? Is there a way to make it like this: public void OrderByMethod(params ...) { .... } so I can call it like this: OrderByMethod(MyEntity.Property1, MyEntity.Property2 descending....); Thanks, Goran

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• Performance of .NET ILMerged assemblies

  - by matt

  I have two .NET libraries: "Foo.Bar" and "Foo.Baz". "Foo.Bar" is self-contained, while "Foo.Baz" references "Foo.Bar". Assuming I do the following: Use ILMerge to merge "Foo.Bar.dll" with "Foo.Baz.dll" into "Foo1.dll". Create a new solution containing the entirity of both "Foo.Bar" and "Foo.Baz" (since I have access to their source code), and compile this into "Foo2.dll". Will there be any differences in the performance of Foo1.dll and Foo2.dll when using their functionality from an external project? If so, how significant is this performance difference, and is it a once-off (on load?) or ongoing difference? Are there any other pros or cons with either approach?

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• Semantic Fish-eye zoom on table cells in UIKit?

  - by niblha

  How would I go about implementing a table view that looks and works something as illustrated in the link below, with UIKit for the iPhone? http://img442.imageshack.us/img442/4177/uifisheyeview.png I was thinking of using UITableView, and was looking a bit at the UITableViewDelegate methods tableView:willDisplayCell:forRowAtIndexPath: tableView:heightForRowAtIndexPath: But it seems as the UITableView will modify the cell frames after these methods are called and just before the cells are drawn? Maybe skipping the UITableView and go straight for some subclassing of a UIScrollView would be a better approach? So my question is basically that I would just like some overall thought in what might be the best ways to use existing UIKit components to implement this type of table view.

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• abstract class MouseAdapter vs. interface

  - by Stefano Borini

  I noted this (it's a java.awt.event class). public abstract class MouseAdapter implements MouseListener, MouseWheelListener, MouseMotionListener { .... } Then you are clearly forced to extend from this adapter public class MouseAdapterImpl extends MouseAdapter {} the class is abstract and implements no methods. Is this a strategy to combine different interfaces into a single "basically interface" ? I assume in java it's not possible to combine different interfaces into a single one without using this approach. In other words, it's not possible to do something like this in java public interface MouseAdapterIface extends MouseListener, MouseWheelListener, MouseMotionListener { } and then eventually public class MouseAdapterImpl implements MouseAdapterIface {} Is my understanding of the point correct ? what about C# ?

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• How to use QMetaMethod with QObject::connect

  - by VestniK

  I have two instances of QObject subclasses and two QMetaMethod instances of signal in one of objects and slot in another object. I want to connect this signal and slot with each other. I've looked through the qobject.h file and find that SIGNAL() and SLOT() macro are just add "1" or "2" character to the beginning of method signature so it looks like it should be possible to add the same character to the beginning of string returned by QMetaMethod::signature() but this approach depends on some undocumented internals of toolkit and may be broken at any time by a new version of Qt. Does anybody know reliable way to connect signals and slots through their QMetaMethod reflection representation?

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• What documents/requirements do you need from clients to develop web projects ?

  - by kacalapy

  I have an interview coming up where I would be a consultant to a small advertising agency. They crank out web sites for clients using DNN. tTe company owner/ operator asked me what I need in order to run with something and get it done, and eluded to wire frames and a site map. I am more used to having more detailed work and in a full time company environment but in these times it looks like we all need to be a bit more flexible. Typically I have functional and non-functional specifications defined for development work. This way I can control what is in scope, manage expectations, get sign offs, track deliverables and so on. Are there any contractors out there who develop web sites andcan advise me on the best approach to this so that I don't look foolish and get burned or taken advantage of? thanks

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• How can I dynamically override a classes "each" method?

  - by rewbs

  Groovy adds each() and a number of other methods to java.lang.Object. I can't figure out how to use the Groovy metaclass to dynamically replace the default each() on a Java class. I can see how to add new methods: MyJavaClass.metaClass.myNewMethod = { closure -> /* custom logic */ } new MyJavaClass().myNewMethod { item -> println item } // runs custom logic But it seems the same approach doesn't work when overriding methods: MyJavaClass.metaClass.each = { closure -> /* custom logic */ } new MyJavaClass().each { item -> println item } // runs Object.each() What am I doing wrong? How can I dynamically override each() in Groovy?

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• How can you configure or extend BITS (Background Intelligent Transfer Service) to read files from a

  - by Mark

  I have a ASP .NET load balanced application (webservice and website). It runs on SQL server. I need to be able to provide large files for download. However, because of the load balancing situation, the files are stored in the SQL database as opposed to the file system. BITS seems to be the best approach. I have full control of the client. However, i don't know how to configure BITS to read the file from the database. I know how to write the C# code for that, but i don't know how to get BITS to hook into it as opposed to reading the file from the file system. Any ideas?

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• Java - SwingWorker - problem in done() method

  - by Yatendra Goel

  I am using javax.swing.SwingWorker for the first time. I want to update a JLabel from the interim result published by the swing worker as follows: publish("Published String"); Now to update the JLabel, I have coded the following: process(List<String> chunks) { if (chunks.size() > 0) { String text = chunks.get(chunks.size() - 1); label.setText(text); } } The above code works but my problem(or to be more specific, my doubt) is as follows: The above swing worker task is an annonymous inner class so it can access label field. But what if I want to make the swing worker class a non-inner class. Should I need to pass label as an argument to the constructor of swing worker class so that the process() method can access. Or Is there any other way? What approach does other developer follow to update UI components from the swing worker class' result when the swing worker class is not an inner class?

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• How to solve the performance decay of a VB.NET 1.1 application?

  - by marco.ragogna

  I have single-thread windows form application written with VB.NET and targeting Framework 1.1. The software communicates with external boards through a serial interface, and it mainly consist of a state machine that run some tests, driven in a loop done with a Timer and an Interval of 50ms. The feedback on the user interface is done through some custom events raised during the tests. The problem that is driving me crazy is that the performance slightly decrease over time, and in particular after 1200/1300 test operations. The memory occupied does not increase over time, it is only the CPU that seems interested by this problem. The strange thing is that, targeting framework 2.0 and using the same identical code, I do not have this problem. I know that is difficult without looking at the code, but do you have suggestions how can I approach the problem?

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• Using SortableRows and know when rows have been moved

  - by DW

  I want to take advantage of the sortableRows property of the jqGrid. How do I detect when a row has been moved. I have studied the documentation and looked for examples but haven't found much. I do believe it is something like jQuery("#grid").sortableRows({connectWith:'#gird', ondrop: function(){ alert("row moved") }}); but that does not work. I can move the rows, but don't seemed to have trapped the event. Is there something wrong with my syntax or my approach in general. Basically, I need to know that the rows have been rearranged so I can be sure they get saved with their new order. Thanks

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