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  • Python to C/C++ const char question

    - by tsukemonoki
    I am extending Python with some C++ code. One of the functions I'm using has the following signature: int PyArg_ParseTupleAndKeywords(PyObject *arg, PyObject *kwdict, char *format, char **kwlist, ...); (link: http://docs.python.org/release/1.5.2p2/ext/parseTupleAndKeywords.html) The parameter of interest is kwlist. In the link above, examples on how to use this function are given. In the examples, kwlist looks like: static char *kwlist[] = {"voltage", "state", "action", "type", NULL}; When I compile this using g++, I get the warning: warning: deprecated conversion from string constant to ‘char*’ So, I can change the static char* to a static const char*. Unfortunately, I can't change the Python code. So with this change, I get a different compilation error (can't convert char** to const char**). Based on what I've read here, I can turn on compiler flags to ignore the warning or I can cast each of the constant strings in the definition of kwlist to char *. Currently, I'm doing the latter. What are other solutions? Sorry if this question has been asked before. I'm new.

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  • How can I dial GPRS/EDGE in Win CE

    - by brontes
    Hello all. I am developing application in python on Windows CE which needs connection to the internet (via GPRS/EDGE). When I turn on the device, the internet connection is not active. It becomes active if I open internet explorer. I would like to activate connection in my application. I'm trying to do this with RasDial function over ctypes library, but I can't get it to work. Is this the right way or I should do something else? Below is my current code. The ResDial function keeps returning error 87 – Invalid parameter. I don't know anymore what is wrong with it. I would really appreciate any kind of help. Thanks in advance. encoding: utf-8 import ppygui as gui from ctypes import * import os class MainFrame(gui.CeFrame): def init(self, parent = None): gui.CeFrame.init(self, title=u"Zgodovina dokumentov", menu="Menu") DWORD = c_ulong TCHAR = c_wchar ULONG_PTR = c_ulong class RASDIALPARAMS(Structure): _fields_ = [("dwSize", DWORD), ("szEntryName", TCHAR*21), ("szPhoneNumber", TCHAR*129), ("szCallbackNumber", TCHAR*49), ("szUserName", TCHAR*257), ("szPassword", TCHAR*257), ("szDomain", TCHAR*16), ] try: param = RASDIALPARAMS() param.dwSize = 1462 # also tried 1464 and sizeof(RASDIALPARAMS()). Makes no difference. param.szEntryName = u"My Connection" param.szPhoneNumber = u"0" param.szCallbackNumber = u"0" param.szUserName = u"0" param.szPassword = u"0" param.szDomain = u"0" iNasConn = c_ulong(0) ras = windll.coredll.RasDial(None, None, param, c_ulong(0xFFFFFFFF), c_voidp(self._w32_hWnd), byref(iNasConn)) print ras, repr(iNasConn) #this prints 87 c_ulong(0L) except Exception, e: print "Error" print e if name == 'main': app = gui.Application(MainFrame(None)) # create an application bound to our main frame instance app.run() #launch the app !

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  • Working with Java using methods and arrays [closed]

    - by jordan
    Hi i'm a newb at java and for one of my labs I have to create a instant messenger client with these requirements: add buddyList instance variable add IMClient constructor to create ArrayList addBuddy method removeBuddy method findBuddy method printBuddyList method what's the best way to go about this? so far I have this: public class IMClient { private String userId; // User id private String password; // Password private int status; // Status code for user: 1 - Online, 2 - Off-line, 3 - Away public IMClient(String userId, String password, int status) { super(); this.userId = userId; this.password = password; this.status = status; } // Returns true if password as a parameter matches password instance variable. public boolean checkPassword(String password) { return this.password.equals(password); } public String toString() { StringBuffer buf = new StringBuffer(100); buf.append(" User id: "); buf.append(userId); buf.append(" Password: "); buf.append(password); buf.append(" Status: "); buf.append(status); return buf.toString(); } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public int getStatus() { return status; } public void setStatus(int status) { this.status = status; } public static void main(String[] args) { } }

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  • Which CSS identifier is used for the selected tab in tabbed tables in browsers other than IE?

    - by David Navarre
    When you have a table on a form in Notes, you can choose to display only one row at a time (via the Special Table Row Display parameter on the Table Rows tab of the Table properties). In a Notes document displayed using Internet Explorer that contains such a table, a row is displayed with a cell for each "tab". The TD that serves as the tab for the selected "Notes table row" is assigned <td class="dominoSelTopTab">, while the other tabs get <td class="dominoTopTab">. However, when using other browsers, it's not nearly as simple. In Firefox, each "tab" ends up as a single-celled-single-row-table within the table with very little to identify it. <td><table border="1" cellpadding="2"> <tr><td><div align="center"><b>Tab 2</b></div></td></tr> </table></td> A non-selected tab would show as follows: <td><table border="1" cellpadding="2"> <tr><td><div align="center"><a name="1." href="/Projects/MyCSS.nsf/0c3b9489476440c085257a62006d97d6/d482a1767a4af77f85257a62006db064?OpenDocument&amp;TableRow=1.0#1." target="_self">Tab 1</a></div></td></tr> </table></td> So, the question is, how do I identify the selected tabs and the non-selected tabs when not using IE? Note: For those who are not Notes developers, the HTML is auto-generated from the visual design as laid out in the Notes designer client. I would replace it all with manual HTML, except there is so much of it that doing so would consume far too much time.

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  • How to call a method in another class in Java?

    - by Puchatek
    Currently I have two classes. a classroom class and a School class. I would like to write a method in the School class to call public void setTeacherName(String newTeacherName) from the classroom class. public class classroom { private String classRoomName; private String teacherName; public void setClassRoomName(String newClassRoomName) { classRoomName = newClassRoomName; } public String returnClassRoomName() { return classRoomName; } public void setTeacherName(String newTeacherName) { teacherName = newTeacherName; } public String returnTeacherName() { return teacherName; } } import java.util.ArrayList; public class School { private ArrayList<classroom> classrooms; private String classRoomName; private String teacherName; public School() { classrooms = new ArrayList<classroom>(); } public void addClassRoom(classroom newClassRoom, String theClassRoomName) { classrooms.add(newClassRoom); classRoomName = theClassRoomName; } // how to write a method to add a teacher to the classroom by using the classroom parameter // and the teachers name }

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  • Word frequency tally script is too slow

    - by Dave Jarvis
    Background Created a script to count the frequency of words in a plain text file. The script performs the following steps: Count the frequency of words from a corpus. Retain each word in the corpus found in a dictionary. Create a comma-separated file of the frequencies. The script is at: http://pastebin.com/VAZdeKXs Problem The following lines continually cycle through the dictionary to match words: for i in $(awk '{if( $2 ) print $2}' frequency.txt); do grep -m 1 ^$i\$ dictionary.txt >> corpus-lexicon.txt; done It works, but it is slow because it is scanning the words it found to remove any that are not in the dictionary. The code performs this task by scanning the dictionary for every single word. (The -m 1 parameter stops the scan when the match is found.) Question How would you optimize the script so that the dictionary is not scanned from start to finish for every single word? The majority of the words will not be in the dictionary. Thank you!

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  • Adding a column to a model at runtime (without additional tables) in rails

    - by Marek
    I'm trying to give admins of my web application the ability to add some new fields to a model. The model is called Artwork and i would like to add, for instante, a test_column column at runtime. I'm just teting, so i added a simple link to do it, it will be of course parametric. I managed to do it through migrations: def test_migration_create Artwork.add_column :test_column, :integer flash[:notice] = "Added Column test_column to artworks" redirect_to :action => 'index' end def test_migration_delete Artwork.remove_column :test_column flash[:notice] = "Removed column test_column from artworks" redirect_to :action => 'index' end It works, the column gets added/ removed to/from the databse without issues. I'm using active_scaffold at the moment, so i get the test_column field in the form without adding anything. When i submit a create or an update, however, the test_column does not get updated and stay empty. Inspecting the parameters, i can see: Parameters: {"commit"=>"Update", "authenticity_token"=>"37Bo5pT2jeoXtyY1HgkEdIhglhz8iQL0i3XAx7vu9H4=", "id"=>"62", "record"=>{"number"=>"test_artwork", "author"=>"", "title"=>"Opera di Test", "test_column"=>"TEEST", "year"=>"", "description"=>""}} the test_column parameter is passed correctly. So why active record keeps ignoring it? I tried to restart the server too without success. I'm using ruby 1.8.7, rails 2.3.5, and mongrel with an sqlite3 database. Thanks

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  • Silverlight logging out causes "Object reference not set to an instance"

    - by Alex
    I am using the Silverlight 4 Business Application Template. I've created a DomainDataSource in XAML like so: <riaControls:DomainDataSource x:Name="LogData" QueryName="GetLogs" AutoLoad="True" LoadSize="20" > <riaControls:DomainDataSource.DomainContext> <local:AdminDomainContext /> </riaControls:DomainDataSource.DomainContext> <riaControls:DomainDataSource.QueryParameters> <riaControls:Parameter ParameterName="UserLoginID" Value="{Binding Path=User.UserLoginID, Source={StaticResource WebContext}}" /> </riaControls:DomainDataSource.QueryParameters> </riaControls:DomainDataSource> The problem I'm experiencing is that whenever I log out, I get: Load operation failed for query 'GetLogs'. Object reference not set to an instance of an object. I assume that because I've logged out, User.UserLoginID is now null and is causing the exception. So... anybody know a good way for me to solve this? I don't really want to set the QueryParameter programmatically.

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  • GNU Makefile: multiple outputs from single rule + preventing intermediate files from being deleted

    - by makesaurus
    This is sort of a continuation of question from link text. The problem is that there is a rule generating multiple outputs from a single input, and the command is time-consuming so we would prefer to avoid recomputation. Now there is an additional twist, that we want to keep files from being deleted as intermediate files, and rules involve wildcards to allow for parameters. The solution suggested was that we set up the following rule: file-a.out: program file.in ./program file.in file-a.out file-b.out file-c.out file-b.out: file-a.out @ file-c.out: file-b.out @ Then, calling make file-c.out creates both and we avoid issues with running make in parallel with -j switch. All fine so far. The problem is the following. Because the above solution sets up a chain in the DAG, make considers it differently; the files file-a.out and file-b.out are treated as intermediate files, and they by default get deleted as unnecessary as soon as file-c.out is ready. A way of avoiding that was mentioned somewhere here, and consists of adding file-a.out and file-b.out as dependencies of a target .SECONDARY, which keeps them from being deleted. Unfortunately, this does not solve my case because my rules use wildcard patters; specifically, my rules look more like this: file-a-%.out: program file.in ./program $* file.in file-a-$*.out file-b-$*.out file-c-$*.out file-b-%.out: file-a-%.out @ file-c-%.out: file-b-%.out @ so that one can pass a parameter that gets included in the file name, for example by running make file-c-12.out The solution that make documentation suggests is to add these as implicit rules to the list of dependencies of .PRECIOUS, thus keeping these files from being deleted. The solution with .PRECIOUS works, but it also prevents these files from being deleted when a rule fails and files are incomplete. Is there any other way to make this work?

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  • "error: Expected a type, got 'classname'" in C++

    - by Bay
    Using the following code: template <typename T> class node { [. . .] }; class b_graph { friend istream& operator>> (istream& in, b_graph& ingraph); friend ostream& operator<< (ostream& out, b_graph& outgraph); public: [...] private: vector<node> vertices; //This line I'm getting: error: type/value mismatch at argument 1 in template parameter list for ‘template<class _Tp, class _Alloc> class std::vector’ error: expected a type, got 'node' error: template argument 2 is invalid On the indicated line. Node is clearly defined before b_graph which uses it - what have I done here?

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  • $this->url() to another subdomain

    - by Supertino7
    Hello, I created subdomain for my application. host_www.type = "Zend_Controller_Router_Route_Hostname" host_www.route = "www.mywebsite.com" host_www.defaults.module = "produits" host_www.defaults.controller = "produits" host_www.defaults.action = "index" fiche_boutique.route = "ficheboutique/:boutique" fiche_boutique.defaults.controller = "boutique" fiche_boutique.defaults.action = "fiche-boutique" fiche_boutique.defaults.module = "default" fiche_boutique.chain = "host_www" host_produits.type = "Zend_Controller_Router_Route_Hostname" host_produits.route = "produits.mywebsite.com" host_produits.defaults.module = "produits" host_produits.defaults.controller = "produits" host_produits.defaults.action = "index" fiche_produit.type = "Zend_Controller_Router_Route_Regex" fiche_produit.route = "([-\w]+).htm" fiche_produit.reverse = "%s.htm" fiche_produit.map.1 = "q" fiche_produit.defaults.module = "produits" fiche_produit.defaults.controller = "produits" fiche_produit.defaults.action = "voir-produit" fiche_produit.chain = "host" I don't know if the syntax in this zend config ini file is correct, in particular for routes chaining. Once I'm on this subdomain, urls constructed with $this-url() like this : <a href="<?= $this->url(array('boutique' => 1234), 'fiche_boutique', true) ?>"> Visit this store </a> still point to the subdomain produits.mywebsite.com, where I want it to point to www.mywebsite.com For the moment, I do this : <a href="http://www.mywebsite.com<?= $this->url(array('boutique' => 1234), 'fiche_boutique', true) ?>"> Visit this store </a> But it's not flexible at all. Is there a solution, a parameter to add, or my config file is wrong ? thanks in advance for your help.

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  • Dropdownlist value not being set when there is a default blank option

    - by uriDium
    I am using ASP.Net MVC. I have a partial view which has a form with dropdownlists. The dropdownlists are set via ViewData. The partial view is used in a Create and Edit page. The create works fine. I get the dropdownlists and the blank option is a "Please select", like so <%= Html.DropDownList("ContactNrType", ViewData["ContactNrType"] as SelectList, "Please Select") %> But this doesn't seem to work for my edit. If I have that extra "Please select" parameter then it does not select the value for the drop down. I am setting the value of the drop down in the controller like so ViewData["ContactNrType"] = new SelectList(new List<string> { "Mobile", "Home", "Work", "Friend" }, candidate.ContactNrType); Any idea as to what I am doing wrong? I want to share the partial view which contains the form between the two pages. So I need the "Please Select" option for the Create. And I need the value set for the Edit (I don't mind that it has an option that still says "Please Select").

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  • wget not completely processing the http call

    - by user578458
    Here is a wget command that executes a HTML / PHP stack report suite that is hosted by a third party - we don't have control over the PHP or HTML page wget --no-check-certificate --http-user=/myacc --http-password=mypass -O /tmp/myoutput.csv "https://myserver.mydomain.com/mymodule.php?myrepcode=9999&action=exportcsv&admin=myappuserid&password=myappuserpass&startdate=2011-01-16&enddate=2011-01-16&reportby=mypreferredview" All the elements are working perfectly: --http-user / --http-pass as offered by a browsers standard popup for username and password prompt -O /tmp/myoutput.csv - the output file of interest https://myserver.mydomain.com/mymodule.php?myrepcode=9999&action=exportcsv&admin=myappuserid&password=myappuserpass&startdate=2011-01-16&enddate=2011-01-16&reportby=mypreferredview" The file generated on the fly by the parameters myrepcode=9999 - a reference to the report in question action=exportcsv internally written in the function admin=myappuserid the third party operats SSL to access the site - then internal username and password stored in a database to access the functions of the site) password=myappuserpass startdate=2011-01-16 this and end data are parameters specific to the report 9999 enddate=2011-01-16 reportby=mypreferredview This is an option in the report that facilitates different levels of detail or aggregation The problem is that the reportby parameter is a radio button selection in a list of 5 selections (sure I enough the default is highest level of aggregation , I want the last one which is the most detailed) Here is a sample of the HTML page code for the options of reportby View by The Default My Least Preferred My Second Least Preferred My Third Least Preferred My Preferred No matter which of the reportby items I select in the wget statement - thedefault is always executed. Questions 1) Has anyone come across this notation in HTML (id=inputname[inputelement]) I spoke to a senior web developer and he has never seen this notation for inputs (id=inputname[inputelement]) - and w3schools do not appear familiar with this either based on an extensive search 2) Can a wget command select a none default radio item when executing the command ? This probably will be initially received with a "Use CURL" response- however the wget approach works very well in the limited environment I am operating in - particularly as I need to download 10000 of these such items. Thanks ahead of response

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  • "2d Search" in Solr or how to get the best item of the multivalued field 'items'?

    - by Karussell
    The title is a bit awkward but I couldn't found a better one. My problem is as follows: I have several users stored as documents and I am storing several key-value-pairs or items (which have an id) for each document. Now, if I apply highlighting I can get the first n items. If you have several hundreds of such items this highlighting is necessary and works nicely. But there are two problems: The highlighted text won't contain the id and so retrieving additional information of the highlighted item text is ugly. E.g. you need to store the id in the text so that the highlighter returns it. Adding the id to the hl.fl parameter does not help. You will not get the most relevant n-items. You will get the first n items ... So how can I find the best items of a documents with multiple such items? I will now add my own findings as answers, but as I will point out. Each of them has its drawbacks. Hopefully anyone of you can point me to a better solution.

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  • Matching Class arrays

    - by frinkz
    I'm writing a routine to invoke methods, found by a name and an array of parameter Class values Matching the Method by getName works, but when trying to match the given Class[] for parameters, and Method.getParameterTypes(), I'm having trouble. I assumed that this would work: Class[] searchParams = new Class[] { float.class, String.class }; Class[] methodParams = m.getParameterTypes(); if(methodParams == searchParams) { m.invoke(this, paramValues); } But apparantly not - m.invoke is never reached. I've checked, and methodParams gives the same classes as searchParams. The code below works, and picks the right method, but it seems like a very dirty way of doing things, I'm sure I'm missing something obvious. Class[] searchParams = new Class[] { float.class, String.class }; Class[] methodParams = m.getParameterTypes(); boolean isMatch = true; for(int i = 0; i < searchParams.length; i++) { if(!searchParams.getClass().equals(methodParams.getClass())) { isMatch = false; } } if(isMatch) { m.invoke(this, paramValues); }

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  • How can I split abstract testcases in JUnit?

    - by Willi Schönborn
    I have an abstract testcase "AbstractATest" for an interface "A". It has several test methods (@Test) and one abstract method: protected abstract A unit(); which provides the unit under testing. No i have multiple implementations of "A", e.g. "DefaultA", "ConcurrentA", etc. My problem: The testcase is huge (~1500 loc) and it's growing. So i wanted to split it into multiple testcases. How can organize/structure this in Junit 4 without the need to have a concrete testcase for every implementation and abstract testcase. I want e.g. "AInitializeTest", "AExectueTest" and "AStopTest". Each being abstract and containing multiple tests. But for my concrete "ConcurrentA", i only want to have one concrete testcase "ConcurrentATest". I hope my "problem" is clear. EDIT Looks like my description was not that clear. Is it possible to pass a reference to a test? I know parameterized tests, but these require static methods, which is not applicable to my setup. Subclasses of an abstract testcase decide about the parameter.

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  • Is it better for class data to be passed internally or accessed directly?

    - by AaronSzy
    Example: // access fields directly private void doThis() { return doSomeWork(this.data); } // receive data as an argument private void doThis(data) { return doSomeWork(data); } The first option is coupled to the value in this.data while the second option avoids this coupling. I feel like the second option is always better. It promotes loose coupling WITHIN the class. Accessing global class data willy-nilly throughout just seems like a bad idea. Obviously this class data needs to be accessed directly at some point. However, if accesses, to this global class data can be eliminated by parameter passing, it seems that this is always preferable. The second example has the advantage of working with any data of the proper type, whereas the first is bound to working with the just class data. Even if you don't NEED the additional flexibility, it seems nice to leave it as an option. I just don't see any advantage in accessing member data directly from private methods as in the first example. Whats the best practice here? I've referenced code complete, but was not able to find anything on this particular issue.

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  • Pitfalls of the Architecture - Database based HTTP Request/Response Parsing

    - by Sam
    We have a current eCommerce Site that runs on ASP.NET and we hired a consultant to develop an new site bases on SOA. The new site architecture is as follows Web Application : Single Page Web Application (built on javascript/jquery templates - do not use any MVVM frameworks) that uses some javascript thrown all over the place. Service Layer : Very very light Service Layer that does not do anything other than calling a single stored procedure and pass in the entire http request. Database : The entire site content is in the database. The database does the heavy lifting of parsing the request and based on the HTTP method and some input parameter calls the appropriate Store Procedures or views and renders the result in JSON/XML. We have been told by them that this is built on latest and greatest technologies. I have a lot of concerns and of them given are the few Load on the Database SEO concerns for single page application as this is a public facing website Scalablity? Is this SOA? Cross Browser compatability (Site does not work in < IE9) Realistic implementaion of Single page application I know something is not right but I just need to validate my concerns here. Please help me.

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  • Jasper Reports and iReport issue

    - by William
    I am having an issue with JasperReports I can not solve. I am using Eclipse, OpenReports 3.2 and IReport 3.7 The issue I am having is that the report does nothing. When I preview the report in IReport I can at least get a "Document has no pages" message but when I try to open it using OpenReports it doesn't do anything. I get the open reports header and the copyright message but nothing between them. I was able to track it down to line 150 in ReportRunAction.java in OpenReports. That line is: jasperPrint = jasperEngine.fillReport(reportInput); At least that is the line the page dies on. It trips the catch block that the line is inside of but the error is empty. When I try to print the description it is null. I can't swear that the issue isn't that parameter. Through looking around all I have been able to find is something about how the report needs to be compiled with the same version of the jasperreports.jar that OpenReports uses. I have no idea how to tell if/what version of jasper reports is being bundled into the .jasper file though. Is that my problem? If so how do I tell/set the version of the jar that gets bundled? If not; help!

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  • [c++] accessing the hidden 'this' pointer

    - by Kyle
    I have a GUI architecture wherein elements fire events like so: guiManager->fireEvent(BUTTON_CLICKED, this); Every single event fired passes 'this' as the caller of the event. There is never a time I dont want to pass 'this', and further, no pointer except for 'this' should ever be passed. This brings me to a problem: How can I assert that fireEvent is never given a pointer other than 'this', and how can I simplify (and homogenize) calls to fireEvent to just: guiManager->fireEvent(BUTTON_CLICKED); At this point, I'm reminded of a fairly common compiler error when you write something like this: class A { public: void foo() {} }; class B { void oops() { const A* a = new A; a->foo(); } }; int main() { return 0; } Compiling this will give you ../src/sandbox.cpp: In member function ‘void B::oops()’: ../src/sandbox.cpp:7: error: passing ‘const A’ as ‘this’ argument of ‘void A::foo()’ discards qualifiers because member functions pass 'this' as a hidden parameter. "Aha!" I say. This (no pun intended) is exactly what I want. If I could somehow access the hidden 'this' pointer, it would solve both issues I mentioned earlier. The problem is, as far as I know you can't (can you?) and if you could, there would be outcries of "but it would break encapsulation!" Except I'm already passing 'this' every time, so what more could it break. So, is there a way to access the hidden 'this', and if not are there any idioms or alternative approaches that are more elegant than passing 'this' every time?

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  • Undefined test not working in javascript.

    - by James South
    I'm getting the error 'foo' is undefined. in my script when i test my function with an undefined parameter. As far as I understand, This shouldn't be happening. My calling code: //var foo var test = peachUI().stringIsNullOrEmpty(foo) ; My function (part of a larger framework). stringIsNullOrEmpty: function (testString) { /// <summary> /// Checks to see if a given string is null or empty. /// </summary> /// <param name="testString" type="String"> /// The string check against. /// </param> /// <returns type="Boolean" /> var $empty = true; if (typeof testString !== "undefined") { if (testString && typeof testString === "string") { if (testString.length > 0) { $empty = false; } } } return $empty; } Any ideas? Please note. I've had a good read of other similar questions before posting this one.

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  • I'm confused about Polymorphism

    - by Vtanathip
    I'm know polymorphism rule that we can send it via parameter like this code interface Animal { void whoAmI(); } class A implements Animal{ @Override public void whoAmI() { // TODO Auto-generated method stub System.out.println("A"); } } class B implements Animal{ @Override public void whoAmI() { // TODO Auto-generated method stub System.out.println("B"); } } class RuntimePolymorphismDemo { public void WhoRU(List t){ System.out.println(t.getClass()); } public static void main(String[] args) { A a = new A(); B b = new B(); RuntimePolymorphismDemo rp = new RuntimePolymorphismDemo(); rp.WhoRU(a); rp.WhoRU(b); } } but List<Example> examples = new ArrayList<Example>(); This code,I'm don't understand why we must use List. why we can't use like this? ArrayList<Example> examples = new ArrayList<Example>(); Because when we use List we can't use method that only have in ArrayList class like trimToSize() and How I know when to use or not use?

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  • Permuting output of a tree of closures

    - by yan
    This a conceptual question on how one would implement the following in Lisp (assuming Common Lisp in my case, but any dialect would work). Assume you have a function that creates closures that sequentially iterate over an arbitrary collection (or otherwise return different values) of data and returns nil when exhausted, i.e. (defun make-counter (up-to) (let ((cnt 0)) (lambda () (if (< cnt up-to) (incf cnt) nil)))) CL-USER> (defvar gen (make-counter 3)) GEN CL-USER> (funcall gen) 1 CL-USER> (funcall gen) 2 CL-USER> (funcall gen) 3 CL-USER> (funcall gen) NIL CL-USER> (funcall gen) NIL Now, assume you are trying to permute a combinations of one or more of these closures. How would you implement a function that returns a new closure that subsequently creates a permutation of all closures contained within it? i.e.: (defun permute-closures (counters) ......) such that the following holds true: CL-USER> (defvar collection (permute-closures (list (make-counter 3) (make-counter 3)))) CL-USER> (funcall collection) (1 1) CL-USER> (funcall collection) (1 2) CL-USER> (funcall collection) (1 3) CL-USER> (funcall collection) (2 1) ... and so on. The way I had it designed originally was to add a 'pause' parameter to the initial counting lambda such that when iterating you can still call it and receive the old cached value if passed ":pause t", in hopes of making the permutation slightly cleaner. Also, while the example above is a simple list of two identical closures, the list can be an arbitrarily-complicated tree (which can be permuted in depth-first order, and the resulting permutation set would have the shape of the tree.). I had this implemented, but my solution wasn't very clean and am trying to poll how others would approach the problem. Thanks in advance.

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  • Efficient way to get highly correlated pairs from large data set in Python or R

    - by Akavall
    I have a large data set (Let's say 10,000 variables with about 1000 elements each), we can think of it as 2D list, something like: [[variable_1], [variable_2], ............ [variable_n] ] I want to extract highly correlated variable pairs from that data. I want "highly correlated" to be a parameter that I can choose. I don't need all pairs to be extracted, and I don't necessarily want the most correlated pairs. As long as there is an efficient method that gets me highly correlated pairs I am happy. Also, it would be nice if a variable does not show up in more than one pair. Although this might not be crucial. Of course, there is a brute force way to finding such pairs, but it is too slow for me. I've googled around for a bit and found some theoretical work on this issue, but I wasn't able for find a package that could do what I am looking for. I mostly work in python, so a package in python would be most helpful, but if there exists a package in R that does what I am looking for it will be great. Does anyone know of a package that does the above in Python or R? Or any other ideas? Thank You in Advance

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  • Increasing understanding of validating a string with PHP string functions

    - by user1554264
    I've just started attempts to validate data in PHP and I'm trying to understand this concept better. I was expecting the string passed as an argument to the $data parameter for the test_input() function to be formatted by the following PHP functions. trim() to remove white space from the end of the string stripslashes() to return a string with backslashes stripped off htmlspecialchars() to convert special characters to HTML entities The issue is that the string that I am echoing at the end of the function is not being formatted in the way I desire at all. In fact it looks exactly the same when I run this code on my server - no white space removed, the backslash is not stripped and no special characters converted to HTML entities. My question is have I gone about this in the wrong approach? Should I be creating the variable called $santised_input on 3 separate lines with each of the functions trim(), stripslashes() and htmlspecialchars()? By my understanding surely I am overwriting the value of the $santised_input variable each time I recreate it on a new line of code. Therefore the trim() and stripslashes() string functions will never be executed. What I am trying to achieve is using the "$santised_input" variable to run all of these PHP string functions when the $data argument is passed to my test_input() function. In other words can these string functions be chained together so that I only need to create $santised_input once? <?php function test_input($data) { $santised_input = trim($data); $santised_input = stripslashes($data); $santised_input = htmlspecialchars($data); echo $santised_input; } test_input("%22%3E%3Cscript%3Ealert('hacked')%3C/script%3E\ "); //Does not output desired result "&quot;&gt;&lt;script&gt;alert('hacked')&lt;/script&gt;" ?>

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