Search Results

Search found 20211 results on 809 pages for 'language implementation'.

Page 672/809 | < Previous Page | 668 669 670 671 672 673 674 675 676 677 678 679  | Next Page >

• Are functional programming languages good for practical tasks?

  - by Clueless

  It seems to me from my experimenting with Haskell, Erlang and Scheme that functional programming languages are a fantastic way to answer scientific questions. For example, taking a small set of data and performing some extensive analysis on it to return a significant answer. It's great for working through some tough Project Euler questions or trying out the Google Code Jam in an original way. At the same time it seems that by their very nature, they are more suited to finding analytical solutions than actually performing practical tasks. I noticed this most strongly in Haskell, where everything is evaluated lazily and your whole program boils down to one giant analytical solution for some given data that you either hard-code into the program or tack on messily through Haskell's limited IO capabilities. Basically, the tasks I would call 'practical' such as Aceept a request, find and process requested data, and return it formatted as needed seem to translate much more directly into procedural languages. The most luck I have had finding a functional language that works like this is Factor, which I would liken to a reverse-polish-notation version of Python. So I am just curious whether I have missed something in these languages or I am just way off the ball in how I ask this question. Does anyone have examples of functional languages that are great at performing practical tasks or practical tasks that are best performed by functional languages?

  Read the article

• How spoof referrer using curl

  - by golu molu

  I am using curl code below to spoof referrer , it works fine but there is error on every page - Curl error: $url = somesite.com function doMagic($url) { $curl = curl_init(); $header[0] = "Accept: text/xml,application/xml,application/xhtml+xml,"; $header[0] .= "text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"; $header[] = "Cache-Control: max-age=0"; $header[] = "Connection: keep-alive"; $header[] = "Keep-Alive: 300"; $header[] = "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7"; $header[] = "Accept-Language: en-us,en;q=0.5"; $header[] = "Pragma: "; curl_setopt($curl, CURLOPT_URL, $url); curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:7.0.1) Gecko/20100101 Firefox/7.0.12011-10-16 20:23:00"); curl_setopt($curl, CURLOPT_HTTPHEADER, $header); curl_setopt($curl, CURLOPT_REFERER, "http://www.facebook.com"); curl_setopt($curl, CURLOPT_ENCODING, "gzip,deflate"); curl_setopt($curl, CURLOPT_AUTOREFERER, true); curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); curl_setopt($curl, CURLOPT_TIMEOUT, 30); curl_setopt($curl, CURLOPT_FOLLOWLOCATION,true); $html = curl_exec($curl); echo 'Curl error: '. curl_error($curl); curl_close($curl); return $html; } $text = doMagic($url); print("$text"); what i'm doing wrong?

  Read the article

• Access 2007 and Special/Unicode Characters in SQL

  - by blockcipher

  I have a small Access 2007 database that I need to be able to import data from an existing spreadsheet and put it into our new relational model. For the most part this seems to work pretty well. Part of the process is attempting to see if a record already exists in a target table using SQL. For example, if I extract book information out of the current row in the spreadsheet, it may contain a title and abstract. I use SQL to get the ID of a matching record, if it exists. This works fine except when I have data that's in a non-English language. In this case, it seems that there is some punctuation that is causing me problems. At least I think it's punctuation as I do have some fields that do not have punctuation and are non-English that do not give me any problems. Is there a built-in function that can escape these characters? Currently I have a small function that will escape the single quote character, but that isn't enough. Or, is there a list of Unicode characters that can interfere with how SQL wants data quoted? Thanks in advance.

  Read the article

• Thread-safe data structure design

  - by Inso Reiges

  Hello, I have to design a data structure that is to be used in a multi-threaded environment. The basic API is simple: insert element, remove element, retrieve element, check that element exists. The structure's implementation uses implicit locking to guarantee the atomicity of a single API call. After i implemented this it became apparent, that what i really need is atomicity across several API calls. For example if a caller needs to check the existence of an element before trying to insert it he can't do that atomically even if each single API call is atomic: if(!data_structure.exists(element)) { data_structure.insert(element); } The example is somewhat awkward, but the basic point is that we can't trust the result of "exists" call anymore after we return from atomic context (the generated assembly clearly shows a minor chance of context switch between the two calls). What i currently have in mind to solve this is exposing the lock through the data structure's public API. This way clients will have to explicitly lock things, but at least they won't have to create their own locks. Is there a better commonly-known solution to these kinds of problems? And as long as we're at it, can you advise some good literature on thread-safe design? EDIT: I have a better example. Suppose that element retrieval returns either a reference or a pointer to the stored element and not it's copy. How can a caller be protected to safely use this pointer\reference after the call returns? If you think that not returning copies is a problem, then think about deep copies, i.e. objects that should also copy another objects they point to internally. Thank you.

  Read the article

• small code redundancy within while-loops (doesn't feel clean)

  - by wallacoloo

  So, in Python (though I think it can be applied to many languages), I find myself with something like this quite often: the_input = raw_input("what to print?\n") while the_input != "quit": print the_input the_input = raw_input("what to print?\n") Maybe I'm being too picky, but I don't like how the line the_input = raw_input("what to print?\n") has to get repeated. It decreases maintainability and organization. But I don't see any workarounds for avoiding the duplicate code without further decreasing the problem. In some languages, I could write something like this: while ((the_input=raw_input("what to print?\n")) != "quit") { print the_input } This is definitely not Pythonic, and Python doesn't even allow for assignment within loop conditions AFAIK. This valid code fixes the redundancy, while 1: the_input = raw_input("what to print?\n") if the_input == "quit": break print the_input But doesn't feel quite right either. The while 1 implies that this loop will run forever; I'm using a loop, but giving it a fake condition and putting the real one inside it. Am I being too picky? Is there a better way to do this? Perhaps there's some language construct designed for this that I don't know of?

  Read the article

• wxGraphicsContext dreadfully slow on Windows

  - by Jonatan

  I've implemented a plotter using wxGraphicsContext. The development was done using wxGTK, and the graphics was very fast. Then I switched to Windows (XP) using wxWidgets 2.9.0. And the same code is extremely slow. It takes about 350 ms to render a frame. Since the user is able to drag the plotter with the mouse to navigate it feels very sluggish with such a slow update rate. I've tried to implement some parts using wxDC and benchmarked the difference. With wxDC the code runs just about 100 times faster. As far as I know both Cairo and GDI+ are implemented in software at this point, so there's no real reason Cairo should be so much faster than GDI+. Am I doing something wrong? Or is the GDI+ implementation just not up on par with Cairo? One small note: I'm rendering to a wxBitmap now, with the wxGraphicsContext created from a wxMemoryDC. This is to avoid flicker on XP, since double buffering doesn't work there.

  Read the article

• JSF - Creating an overlay for popup panels.

  - by Ben

  Hi, I've created an overlay that will popup whenever someone wants to upload a file to the system. The Gui looks like this (when the overlay is up) I have two problems with this: I attached a a4j:support object that, onclick, makes the overlay disappear. The problem with this is that when I click the upload button on the upload component, support catches the click event and closes the overlay with the upload component before I have the chance to finish the operation. I chose two different style classes. One for the overlay and one for the upload panel. But the styling of the overlay takes over the upload component and it becomes transparent as well. The implementation looks something like this: <h:panelgroup layout="block" styleClass="overlayClass"> <rich:fileUpload styleClass="uploadStyleClass"... /> <a4j:support event="onclick" action="#{mrBean.switchOverlayState}" reRender="..."/> </h:panelGroup> The CSS: .overlayClass { Opacity: 0.5; position: fixed; left: 0; right: 0; top: 0; bottom: 0; background: #000; } .uploadStyleClass { opacity: 1.0; ... } Thanks for the help!

  Read the article

• How can I compare market data feed sources for quality and latency improvement?

  - by yves Baumes

  I am in the very first stages of implementing a tool to compare 2 market data feed sources in order to prove the quality of new developed sources to my boss ( meaning there are no regressions, no missed updates, or wrong ), and to prove latencies improvement. So the tool I need must be able to check updates differences as well as to tell which source is the best (in term of latency). Concrectly, reference source could be Reuters while the other one is a Feed handler we develop internally. People warned me that updates might not arrive in the same order as Reuters implementation could differs totally from ours. Therefore a simple algorithm based on the fact that updates could arrive in the same order is likely not to work. My very first idea would be to use fingerprint to compare feed sources, as Shazaam application does to find the title of the tube you are submitting. Google told me it is based on FFT. And I was wondering if signal processing theory could behaves well with market access applications. I wanted to know your own experience in that field, is that possible to develop a quite accurate algorithm to meet the needs? What was your own idea? What do you think about fingerprint based comparison?

  Read the article

• Why does Tex/Latex not speed up in subsequent runs?

  - by Debilski

  I really wonder, why even recent systems of Tex/Latex do not use any caching to speed up later runs. Every time that I fix a single comma*, calling Latex costs me about the same amount of time, because it needs to load and convert every single picture file. (* I know that even changing a tiny comma could affect the whole structure but of course, a well-written cache format could see the impact of that. Also, there might be situations where 100% correctness is not needed as long as it’s fast.) Is there something in the language of Tex which makes this complicated or impossible to accomplish or is it just that in the original implementation of Tex, there was no need for this (because it would have been slow anyway on those large computers)? But then on the other hand, why doesn’t this annoy other people so much that they’ve started a fork which has some sort of caching (or transparent conversion of Tex files to a format which is faster to parse)? Is there anything I can do to speed up subsequent runs of Latex? Except from putting all the stuff into chapterXX.tex files and then commenting them out?

  Read the article

• Rails: generating URLs for actions in JSON response

  - by Chris Butler

  In a view I am generating an HTML canvas of figures based on model data in an app. In the view I am preloading JSON model data in the page like this (to avoid an initial request back): <script type="text/javascript" charset="utf-8"> <% ActiveRecord::Base.include_root_in_json = false -%> var objects = <%= @objects.to_json(:include => :other_objects) %>; ... Based on mouse (or touch) interaction I want to redirect to other parts of my app that are model specific (such as view, edit, delete, etc.). Rather than hard code the URLs in my JavaScript I want to generate them from Rails (which means it always adapts the latest routes). It seems like I have one of three options: Add an empty attr to the model that the controller fills in with the appropriate URL (we don't want to use routes in the model) before the JSON is generated Generate custom JSON where I add the different URLs manually Generate the URL as a template from Rails and replace the IDs in JavaScript as appropriate I am starting to lean towards #1 for ease of implementation and maintainability. Are there any other options that I am missing? Is #1 not the best? Thanks! Chris

  Read the article

• Why is my code slower using #import "progid:typelib" than using "MFC Class From TypeLib"?

  - by Pakman

  I am writing an automation client in Visual C++ with MFC. If I right-click on my solution » Add » Class, I have the option to select MFC Class From TypeLib. Selecting this option generates source/header files for all interfaces. This allows me to write code such as: #include "CApplication.h" #include "CDocument.h" // ... connect to automation server ... CApplication *myApp = new CApplication(pDisp); CDocument myDoc = myApp->get_ActiveDocument(); Using this method, my benchmarking function that makes about 12000 automation calls takes 1 second. Meanwhile, the following code: #import "progid:Library.Application" Library::IApplicationPtr myApp; // ... connect to automation server ... Library::IDocumentPtr myDoc = myApp->GetActiveDocument(); takes about 2.4 seconds for the same benchmark. I assume the smart-pointer implementation is slowing me down, but I don't know why. Even worse, I'm not sure how to use #import construct to achieve the speeds that the first method yields. Is this possible? How or why not? Thanks for your time!

  Read the article

• Algorithm for count-down timer that can add on time

  - by Person

  I'm making a general timer that has functionality to count up from 0 or count down from a certain number. I also want it to allow the user to add and subtract time. Everything is simple to implement except for the case in which the timer is counting down from some number, and the user adds or subtracts time from it. For example: (m_clock is an instance of SFML's Clock) float Timer::GetElapsedTime() { if ( m_forward ) { m_elapsedTime += m_clock.GetElapsedTime() - m_elapsedTime; } else { m_elapsedTime -= m_elapsedTime - m_startingTime + m_clock.GetElapsedTime(); } return m_elapsedTime; } To be a bit more clear, imagine that the timer starts at 100 counting down. After 10 seconds, the above function would look like 100 -= 100 - 100 + 10 which equals 90. If it was called after 20 more seconds it would look like 90 -= 90 - 100 + 30 which equals 70. This works for normal counting, but if the user calls AddTime() ( just m_elapsedTime += arg ) then the algorithm for backwards counting fails miserably. I know that I can do this using more members and keeping track of previous times, etc. but I'm wondering whether I'm missing some implementation that is extremely obvious. I'd prefer to keep it as simple as possible in that single operation.

  Read the article

• Why is my UITableView not being set?

  - by Jamie L

  I checked using the debbuger in the viewDidLoad method and tracerTableView is 0x0 which i assume means it is nil. I don't understand. I should go ahaed say yes I have already checked my nib file and yes all the connections are correct. Here is the header file and the begging of the .m. ///////////// .h file //////////// @interface TrackerListController : UITableViewController { // The mutable (modifiable) dictionary days holds all the data for the days tab NSMutableArray *trackerList; UITableView *tracerTableView; } @property (nonatomic, retain) NSMutableArray *trackerList; @property (nonatomic, retain) IBOutlet UITableView. *tracerTableView; //The addPackage: method is invoked when the user taps the addbutton created at runtime. -(void) addPackage : (id) sender; @end /////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////// .m file ////////////////////////////////////// @implementation TrackerListController @synthesize trackerList, tracerTableView; (void)viewDidLoad { [super viewDidLoad]; self.title = @"Package Tracker"; self.navigationItem.leftBarButtonItem = self.editButtonItem; UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(addPackage:)]; // Set up the Add custom button on the right of the navigation bar self.navigationItem.rightBarButtonItem = addButton; [addButton release]; // Release the addButton from memory since it is no longer needed }

  Read the article

• How can I optimize retrieving lowest edit distance from a large table in SQL?

  - by Matt

  Hey, I'm having troubles optimizing this Levenshtein Distance calculation I'm doing. I need to do the following: Get the record with the minimum distance for the source string as well as a trimmed version of the source string Pick the record with the minimum distance If the min distances are equal (original vs trimmed), choose the trimmed one with the lowest distance If there are still multiple records that fall under the above two categories, pick the one with the highest frequency Here's my working version: DECLARE @Results TABLE ( ID int, [Name] nvarchar(200), Distance int, Frequency int, Trimmed bit ) INSERT INTO @Results SELECT ID, [Name], (dbo.Levenshtein(@Source, [Name])) As Distance, Frequency, 'False' As Trimmed FROM MyTable INSERT INTO @Results SELECT ID, [Name], (dbo.Levenshtein(@SourceTrimmed, [Name])) As Distance, Frequency, 'True' As Trimmed FROM MyTable SET @ResultID = (SELECT TOP 1 ID FROM @Results ORDER BY Distance, Trimmed, Frequency) SET @Result = (SELECT TOP 1 [Name] FROM @Results ORDER BY Distance, Trimmed, Frequency) SET @ResultDist = (SELECT TOP 1 Distance FROM @Results ORDER BY Distance, Trimmed, Frequency) SET @ResultTrimmed = (SELECT TOP 1 Trimmed FROM @Results ORDER BY Distance, Trimmed, Frequency) I believe what I need to do here is to.. Not dumb the results to a temporary table Do only 1 select from `MyTable` Setting the results right in the select from the initial select statement. (Since select will set variables and you can set multiple variables in one select statement) I know there has to be a good implementation to this but I can't figure it out... this is as far as I got: SELECT top 1 @ResultID = ID, @Result = [Name], (dbo.Levenshtein(@Source, [Name])) As distOrig, (dbo.Levenshtein(@SourceTrimmed, [Name])) As distTrimmed, Frequency FROM MyTable WHERE /* ... yeah I'm lost */ ORDER BY distOrig, distTrimmed, Frequency Any ideas?

  Read the article

• PHP Object References in Frameworks

  - by bigstylee

  Before I dive into the disscusion part a quick question; Is there a method to determine if a variable is a reference to another variable/object? For example $foo = 'Hello World'; $bar = &$foo; echo (is_reference($bar) ? 'Is reference' : 'Is orginal'; I have been using PHP5 for a few years now (personal use only) and I would say I am moderately reversed on the topic of Object Orientated implementation. However the concept of Model View Controller Framework is fairly new to me. I have looked a number of tutorials and looked at some of the open source frameworks (mainly CodeIgnitor) to get a better understanding how everything fits together. I am starting to appreciate the real benefits of using this type of structure. I am used to implementing object referencing in the following technique. class Foo{ public $var = 'Hello World!'; } class Bar{ public function __construct(){ global $Foo; echo $Foo->var; } } $Foo = new Foo; $Bar = new Bar; I was surprised to see that CodeIgnitor and Yii pass referencs of objects and can be accessed via the following method: $this->load->view('argument') The immediate advantage I can see is a lot less code and more user friendly. But I do wonder if it is more efficient as these frameworks are presumably optimised? Or simply to make the code more user friendly? This was an interesting article Do not use PHP references.

  Read the article

• Technology Plan - Which tools should I use?

  - by Armadillo

  Hi, Soon, I'll start my own software company. My primary product/solution will be a Billing/Invoice Software. In a near future, I pretend to expand this first module to an ERP. My app should be able to run as a stand-alone application and as a Web-based application (so there will be, probably two GUI for the same Database). My problem, now, is to choose the right tools; I'm talking about what programming language(s) should I use, what kind of database should I choose, and stuff like that. I'm primarily a VB6 programmer, so probably I'll choose the .net framework (vb/c#). But I'm seriously thinking about Java. Java has 2 "pros" that I really like: write once, run anywhere and it is free (I think...). I've been thinking about RIAs too, but I just don't have any substantial feedback about them... Then, I'll need a report tool. Crystal Reports? HTML based Reports? Other? Databases: I'm not sure if I should use SQL-Server Express or PostgreSQL (or other). I'd be happy to hear any comments and advices Thanks

  Read the article

• simplemodal - IE8 $.support.boxModel is not NULL and no object

  - by tom007

  Hi, I try to use the simplmodal script from: http://www.ericmmartin.com/projects/simplemodal/ I got this error $.support.boxModel is not NULL.. in IE8. jquery.simplemodal-1.3.4.min.js?F This is my implementation scipt.. what I have to change to avoid this error? function loadIframe(url){ $.modal('<iframe src="' + url + '" height="700px" width="600px" scrolling="no">', { containerCss:{ backgroundColor:"#fff", borderColor:"#333", }, overlayClose:true, opacity:70, overlayCss: { backgroundColor:"#000" }, onOpen: function (dialog) { dialog.overlay.fadeIn('slow', function () { dialog.container.toggleClass("preloader"); dialog.data.hide(); dialog.container.fadeIn('slow', function () { dialog.container.toggleClass("preloader"); dialog.data.slideDown('slow'); }); }); }, onClose: function (dialog) { dialog.data.fadeOut('slow', function () { dialog.container.slideUp('slow', function () { dialog.overlay.fadeOut('slow', function () { $.modal.close(); // must call this! }); }); }); } }); } $(document).ready(function(){ $("img").click(function(){ var baseurl = location.host; var url = $(this).attr("target"); var url = 'http://' + baseurl + url; loadIframe(url); }); });

  Read the article

• "The data types text and nvarchar are incompatible in the equal to operator" in SQL Query

  - by kenom

  Why i get this error: The data types text and nvarchar are incompatible in the equal to operator. The field of "username" in database is text type... This is my soruce: <%@ Control Language="C#" AutoEventWireup="true" CodeFile="my_answers.ascx.cs" Inherits="kontrole_login_my_answers" %> <div style=" margin-top:-1280px; float:left;"> <p></p> <div id="question"> Add question </div> </div> <asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1" > </asp:GridView> <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:estudent_piooConnectionString %>" SelectCommand="SELECT * FROM [question] WHERE ([username] = @fafa)"> <SelectParameters> <asp:QueryStringParameter Name="fafa" QueryStringField="user" Type="String"/> </SelectParameters> </asp:SqlDataSource>

  Read the article

• OracleGlobalization.SetThreadInfo() ORA-12705 Error

  - by michele

  Hi guys! I'm stuck in a problem, i cannot workaround! I have a Oracle client 11, with registry key set to AMERICAN_AMERICA.WE8ISO8859P1. I cannot edit this key, but my application must get data from Oracle in Italian culture format. So I want to edit culture info form my application only. I'm trying to using OracleGlobalization class in ODP.NET library before my Application.Run(), to set culture for my thread: OracleGlobalization og = OracleGlobalization.GetThreadInfo(); //OracleGlobalization.SetThreadInfo(OracleGlobalization.GetThreadInfo()); og.Calendar = "GREGORIAN"; og.Comparison = "BINARY"; og.Currency = "€"; og.DateFormat = "DD-MON-RR"; og.DateLanguage = "ITALIAN"; og.DualCurrency = "€"; og.ISOCurrency = "ITALY"; og.Language = "ITALIAN"; og.LengthSemantics = "BYTE"; og.NCharConversionException = false; og.NumericCharacters = ",."; og.Sort = "WEST_EUROPEAN"; og.Territory = "ITALY"; OracleGlobalization.SetThreadInfo(og); I get always the same error: ORA-12705: Cannot access NLS data files or invalid environment specified. I really don't know ho to solve this problem! Any hint? I'm working on a Win7 pc with VisualStudio 2008. Thank you in advance!

  Read the article

• Values are not returning from MY SQL database to my java class

  - by sam

  Hi, This is my Query DELIMITER $$ DROP PROCEDURE IF EXISTSdiscoverdb.getuser_info$$ # MySQL returned an empty result set (i.e. zero rows). `CREATE PROCEDURE discoverdb.getuser_info ( IN name VARCHAR(100), IN pass VARCHAR(100) ) BEGIN SELECT * FROM ad_user WHERE sLogin = name AND sPassHash=password(pass); END $$ # MySQL returned an empty result set (i.e. zero rows). DELIMITER ; This is my calling method public Authentication getAuthentication (String username,String password) { //TODO write your implementation code here: Authentication ack = new Authentication(); try{ String simpleProc = "{ call getuser_infosam(?,?)}"; java.sql.CallableStatement cs = con.prepareCall(simpleProc); cs.setString(1, username); cs.setString(2, password); java.sql.ResultSet rs = cs.executeQuery(); while (rs.next()) { System.out.println(rs.getString("sLogin")); System.out.println(rs.getString("sPassHash")); System.out.println(rs.getString("sForename")); System.out.println(rs.getString("sName")); System.out.println(rs.getString("company")); System.out.println(rs.getString("sEmail")); rs.close();} }catch ( Exception e) { e.printStackTrace(); System.out.print(e); } return ack; }

  Read the article

• I can not use Session In Page_Load and I got error bellow

  - by LostLord

  hi my dear friends .... why i got this error : Object reference not set to an instance of an object. when i put this code in my page_load.: protected void Page_Load(object sender, EventArgs e) { BackEndUtils.OverallLoader(); string Teststr = Session["Co_ID"].ToString(); } ========================================================================== this session is made when user logins to my web site and this session works in other areas... thanks for your attention ========================================================================== thanks for your answers i removed BackEndUtils.OverallLoader(); but error still exists i tried Teststr = Convert.ToString(Session["Co_ID"]); and error disappeared - but i don't know why that session is null in other areas that session works perfectly = such as a button in that form what is the matter? my web page markup is like this : <%@ Page Title="" Language="C#" MasterPageFile="~/Admin/AdminBackend.Master" AutoEventWireup="true" CodeBehind="Personel.aspx.cs" Inherits="Darman.Admin.Personel" Theme="DefaultTheme" %> ================================================================================= i put this code in a button like this : string Teststr = Convert.ToString(Session["Co_ID"]); when i press that button THIS code in page Load(POSTBACK) + IN Button_Click works perfectly and shows me 23 (my Co_ID) But when i run my page in browser (first time) this code in page load shows me null. why? thanks a lot

  Read the article

• C# how to calculate hashcode from an object reference.

  - by Wayne

  Folks, here's a thorny problem for you! A part of the TickZoom system must collect instances of every type of object into a Dictionary< type. It is imperative that their equality and hash code be based on the instance of the object which means reference equality instead of value equality. The challenge is that some of the objects in the system have overridden Equals() and GetHashCode() for use as value equality and their internal values will change over time. That means that their Equals and GetHashCode are useless. How to solve this generically rather than intrusively? So far, We created a struct to wrap each object called ObjectHandle for hashing into the Dictionary. As you see below we implemented Equals() but the problem of how to calculate a hash code remains. public struct ObjectHandle : IEquatable<ObjectHandle>{ public object Object; public bool Equals(ObjectHandle other) { return object.ReferenceEquals(this.Object,other.Object); } } See? There is the method object.ReferenceEquals() which will compare reference equality without regard for any overridden Equals() implementation in the object. Now, how to calculate a matching GetHashCode() by only considering the reference without concern for any overridden GetHashCode() method? Ahh, I hope this give you an interesting puzzle. We're stuck over here. Sincerely, Wayne

  Read the article

• wcf class implementing multiple service contracts

  - by Archie

  Hello, I have a class TestService which implements two service contracts called IService1 and IService2. But I'm facing a difficulty in implementation. My Code looks as follows: Uri baseAddress = new Uri("http://localhost:8000/ServiceModel/Service"); Uri baseAddress1 = new Uri("http://localhost:8080/ServiceModel/Service1"); ServiceHost selfHost = new ServiceHost(typeof(TestService)); selfHost.AddServiceEndpoint(typeof(IService1), new WSHttpBinding(), baseAddress); selfHost.AddServiceEndpoint(typeof(IService2), new WSHttpBinding(), baseAddress1); ServiceMetadataBehavior smb = new ServiceMetadataBehavior(); smb.HttpGetEnabled = true; selfHost.Description.Behaviors.Add(smb); selfHost.Open(); Console.WriteLine("The service is ready."); Console.WriteLine("Press <ENTER> to terminate service."); Console.WriteLine(); Console.ReadLine(); selfHost.Close(); I'm getting a run time error as: The HttpGetEnabled property of ServiceMetadataBehavior is set to true and the HttpGetUrl property is a relative address, but there is no http base address. Either supply an http base address or set HttpGetUrl to an absolute address. What shall i do about it? Do I realy need two separate endpoints? Thanks.

  Read the article

• Why Illegal cookies are send by Browser and received by web servers (rfc2109)?

  - by Artyom

  Hello, According to RFC 2109 cookie's value can be either HTTP token or quoted string, and token can't include non-ASCII characters. Cookie's RFC 2109: http://tools.ietf.org/html/rfc2109#page-3 HTTP's RFC 2068 token definition: http://tools.ietf.org/html/rfc2068#page-16 However I had found that Firefox browser (3.0.6) sends cookies with utf-8 string as-is and three web servers I tested (apache2, lighttpd, nginx) pass this string as-is to the application. For example, raw request from browser: $ nc -l -p 8080 GET /hello HTTP/1.1 Host: localhost:8080 User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.9) Gecko/2009050519 Firefox/2.0.0.13 (Debian-3.0.6-1) Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: windows-1255,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Cookie: wikipp=1234; wikipp_username=?????? Cache-Control: max-age=0 And raw response of apache, nginx and lighttpd HTTP_COOKIE CGI variable: wikipp=1234; wikipp_username=?????? What do I miss? Can somebody explain me?

  Read the article

• Pairs from single list

  - by Apalala

  Often enough, I've found the need to process a list by pairs. I was wondering which would be the pythonic and efficient way to do it, and found this on Google: pairs = zip(t[::2], t[1::2]) I thought that was pythonic enough, but after a recent discussion involving idioms versus efficiency, I decided to do some tests: import time from itertools import islice, izip def pairs_1(t): return zip(t[::2], t[1::2]) def pairs_2(t): return izip(t[::2], t[1::2]) def pairs_3(t): return izip(islice(t,None,None,2), islice(t,1,None,2)) A = range(10000) B = xrange(len(A)) def pairs_4(t): # ignore value of t! t = B return izip(islice(t,None,None,2), islice(t,1,None,2)) for f in pairs_1, pairs_2, pairs_3, pairs_4: # time the pairing s = time.time() for i in range(1000): p = f(A) t1 = time.time() - s # time using the pairs s = time.time() for i in range(1000): p = f(A) for a, b in p: pass t2 = time.time() - s print t1, t2, t2-t1 These were the results on my computer: 1.48668909073 2.63187503815 1.14518594742 0.105381965637 1.35109519958 1.24571323395 0.00257992744446 1.46182489395 1.45924496651 0.00251388549805 1.70076990128 1.69825601578 If I'm interpreting them correctly, that should mean that the implementation of lists, list indexing, and list slicing in Python is very efficient. It's a result both comforting and unexpected. Is there another, "better" way of traversing a list in pairs? Note that if the list has an odd number of elements then the last one will not be in any of the pairs. Which would be the right way to ensure that all elements are included? I added these two suggestions from the answers to the tests: def pairwise(t): it = iter(t) return izip(it, it) def chunkwise(t, size=2): it = iter(t) return izip(*[it]*size) These are the results: 0.00159502029419 1.25745987892 1.25586485863 0.00222492218018 1.23795199394 1.23572707176 Results so far Most pythonic and very efficient: pairs = izip(t[::2], t[1::2]) Most efficient and very pythonic: pairs = izip(*[iter(t)]*2) It took me a moment to grok that the first answer uses two iterators while the second uses a single one. To deal with sequences with an odd number of elements, the suggestion has been to augment the original sequence adding one element (None) that gets paired with the previous last element, something that can be achieved with itertools.izip_longest().

  Read the article

< Previous Page | 668 669 670 671 672 673 674 675 676 677 678 679  | Next Page >