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  • Java - How to declare table[i][j] elements as instance variables?

    - by JDelage
    All, I am trying to code a Connect4 game. For this, I have created a P4Game class and a P4Board class which represents the i X j dimensions of the Connect4 board. In P4Game, I have the following: public class P4Game{ //INSTANCE VARIABLES private int nbLines; private int nbColumns; private P4Board [][] position; //CONSTRUCTOR public P4Game(int nbLines, int nbColumns){ this.nbColumns = nbColumns; this.nbLines = nbLines; P4Board [][] position = new P4Board [nbLines][nbColumns]; //Creates the table to receive the instances of the P4Board object.*/ for (int i=0; i<nbLines; i++){ for (int j=0; j<nbColumns; j++){ this.position[i][j] = new P4Board(i,j); //Meant to create each object at (line=i, column=j) } } } This causes a NullPointerException in the nested loops where I mention this.position[i][j]. I reference those objects in other methods of this class so I need them to be instance variables. I suppose the exception is due to the fact that I have not listed the table element position[i][j] as an instance variable at the beginning of the class. my question to people here is (1) is my assumption correct, and if so (2) what would be the syntax to declare instance variables of this form? Thank you all for your help with what I realize is a very basic question. Hopefully it will also benefit other newbies. Cheers, JDelage

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  • How do I use Core Data with the Cocoa Text Input system?

    - by the Joel
    Hobbyist Cocoa programmer here. Have been looking around all the usual places, but this seems relatively under-explained: I am writing something a little out of the ordinary. It is much simpler than, but similar to, a desktop publishing app. I want editable text boxes on a canvas, arbitrarily placed. This is document-based and I’d really like to use Core Data. Now, The cocoa text-handling system seems to deal with a four-class structure: NSTextStorage, NSLayoutManager, NSTextContainer and finally NSTextView. I have looked into these and know how to use them, sort of. Have been making some prototypes and it works for simple apps. The problem arrives when I get into persistency. I don't know how to, by way of Cocoa Bindings or something else, store the contents of NSTextStorage (= the actual text) in my managed object context. I have considered overriding methods pairs like -words, -setWords: in these objects. This would let me link the words to a String, which I know how to store in Core Data. However, I’d have to override any method that affects the text - and that seems a little much. Thankful for any insights.

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  • MS Access (Jet) transactions, workspaces & scope

    - by Eric G
    I am having trouble with committing a transaction (using Access 2003 DAO). It's acting as if I never had called BeginTrans -- I get error 3034 on CommitTrans, "You tried to commit or rollback a transaction without first beginning a transaction"; and the changes are written to the database (presumably because they were never wrapped in a transaction). However, BeginTrans is run, if you step through it. I am running it within the Access environment using the DBEngine(0) workspace. The tables I'm updating are all opened via a Jet database connection (to the same database) and updated using DAO.Recordset.update. The connection is opened before starting BeforeTrans. I'm not doing anything weird in the middle of the transaction like closing/opening connections or multiple workspaces etc. There is one nested transaction level (basically it's wrapping multiple transacted updates in an outer transaction, so if any fail they all fail). The inner transactions run without errors, it's the outer transaction that doesn't work. Here are a few things I've looked into and ruled out: The transaction is spread across several methods and BeginTrans and CommitTrans (and Rollback) are all in different places. But when I tried a simple test of running a transaction this way, it doesn't seem like this should matter. I thought maybe the database connection gets closed when it goes out of local scope, even though I have another 'global' reference to it (I'm never sure what DAO does with dbase connections to be honest). But this seems not to be the case -- right before the commit, the connection and its recordsets are alive (I can check their properties, EOF = False, etc.) My CommitTrans and Rollback are done within event callbacks. (Very basically, a parser program is throwing an 'onLoad' or 'onLoadFail' event at the end of parsing, which I am handling by either committing or rolling back the inserts I made during processing.) However, again, trying a simple test, it doesn't seem like this should matter. Any ideas why this isn't working for me? Thanks.

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  • Help me clean up this crazy lambda with the out keyword

    - by Sarah Vessels
    My code looks ugly, and I know there's got to be a better way of doing what I'm doing: private delegate string doStuff( PasswordEncrypter encrypter, RSAPublicKey publicKey, string privateKey, out string salt ); private bool tryEncryptPassword( doStuff encryptPassword, out string errorMessage ) { ...get some variables... string encryptedPassword = encryptPassword(encrypter, publicKey, privateKey, out salt); ... } This stuff so far doesn't bother me. It's how I'm calling tryEncryptPassword that looks so ugly, and has duplication because I call it from two methods: public bool method1(out string errorMessage) { string rawPassword = "foo"; return tryEncryptPassword( (PasswordEncrypter encrypter, RSAPublicKey publicKey, string privateKey, out string salt) => encrypter.EncryptPasswordAndDoStuff( // Overload 1 rawPassword, publicKey, privateKey, out salt ), out errorMessage ); } public bool method2(SecureString unencryptedPassword, out string errorMessage) { return tryEncryptPassword( (PasswordEncrypter encrypter, RSAPublicKey publicKey, string privateKey, out string salt) => encrypter.EncryptPasswordAndDoStuff( // Overload 2 unencryptedPassword, publicKey, privateKey, out salt ), out errorMessage ); } Two parts to the ugliness: I have to explicitly list all the parameter types in the lambda expression because of the single out parameter. The two overloads of EncryptPasswordAndDoStuff take all the same parameters except for the first parameter, which can either be a string or a SecureString. So method1 and method2 are pretty much identical, they just call different overloads of EncryptPasswordAndDoStuff. Any suggestions? Edit: if I apply Jeff's suggestions, I do the following call in method1: return tryEncryptPassword( (encrypter, publicKey, privateKey) => { var result = new EncryptionResult(); string salt; result.EncryptedValue = encrypter.EncryptPasswordAndDoStuff( rawPassword, publicKey, privateKey, out salt ); result.Salt = salt; return result; }, out errorMessage ); Much the same call is made in method2, just with a different first value to EncryptPasswordAndDoStuff. This is an improvement, but it still seems like a lot of duplicated code.

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  • eclipse show errors but compiles when external makefile

    - by Anthony
    I have some c++ code using CImg and Eigen libraries. At the c++ code I define a plugin like this #define cimg_plugin1 "my_plugin.h" #include "CImg.h" The plugin contains many method definitions that are used at the c++ code. I also have a makefile that when called from the command line (./make), allows me to compile everything, and generates an executable. I want to import this code into a new Eclipse project, and I do it so: NewProjectC++ projectmakefile projectempty project unmark "Use default location", and select the folder containing my code at the filesystem ProjectpropertiesC/C++ Buildunmark "Use default build command" and set it to use my makefile Also in project propertiesC/C++ GeneralPaths and SymbolsAdd paths to folders containing Eigen and CImg Rebuild index Clean project Restart eclipse When I build the project, eclipse tells me I have more than 1000 errors in "my_plugin.h", but it is capable to generate the executable. Even though, I would like to get rid of this errors, because they are annoying. Also, if I want to open the declaration of CImg methods used at the plugin, I can't. I know it has been asked before, but any of the solutions I found were satisfactory for me (most of them enumerated at the previous list). The sources I visited are the following, and I would be really happy if you find and tell me others I didn't see. Eclipse shows errors but project compile fine eclipse C project shows errors (Symbol could not be resolved) but it compiles Eclipse CDT shows some errors, but the project is successfully built http://www.eclipse.org/forums/index.php/t/247954/

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  • using ini file in vb6, problem with path to file

    - by DrPut
    I have read many articles about how to use an INI file within my VB6 project. I don't have a problem with the methods, my problem is how to make the EXE file find the INI file. I don't want to hard code the path in the program. I simply want the EXE to expect the INI file to be present in the same folder the EXE is executed from. When I run the program from inside VB6 IDE, the INI is found and processed. When I compile the program and run the EXE, nothing is found. My code looks like: gServer = sGetINI(sINIFile, "TOOLBOM", "ServerName", "?") where TOOLBOM is the [Section] and "ServerName" is the key for the value. I obtained the following code for the API: Rem API DECLARATIONS Declare Function GetPrivateProfileString Lib "kernel32" Alias _ "GetPrivateProfileStringA" (ByVal lpApplicationName _ As String, ByVal lpKeyName As Any, ByVal lpDefault _ As String, ByVal lpReturnedString As String, ByVal _ nSize As Long, ByVal lpFileName As String) As Long Declare Function WritePrivateProfileString Lib "kernel32" Alias _ "WritePrivateProfileStringA" (ByVal lpApplicationName _ As String, ByVal lpKeyName As Any, ByVal lpString As Any, _ ByVal lpFileName As String) As Long Public Function sGetINI(sINIFile As String, sSection As String, sKey _ As String, sDefault As String) As String Dim sTemp As String * 256 Dim nLength As Integer sTemp = Space$(256) nLength = GetPrivateProfileString(sSection, sKey, sDefault, sTemp, _ 255, sINIFile) sGetINI = Left$(sTemp, nLength) End Function Public Sub writeINI(sINIFile As String, sSection As String, sKey _ As String, sValue As String) Dim n As Integer Dim sTemp As String sTemp = sValue Rem Replace any CR/LF characters with spaces For n = 1 To Len(sValue) If Mid$(sValue, n, 1) = vbCr Or Mid$(sValue, n, 1) = vbLf _ Then Mid$(sValue, n) = " " Next n n = WritePrivateProfileString(sSection, sKey, sTemp, sINIFile) End Sub

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  • handle large Parcelable ArrayList in Android

    - by Gal Ben-Haim
    I'm developing an Android app that is a client to a JSON webservice API. I have classes of resource objects (some are nested) and I pass results from an IntentService that access the webserive using the Parcelable interface for all the resource classes. the webservice returns arrays or results that can be potentially large (because of the nesting, for example, a post object also contains comments array, each comment also contains a user object). currently I'm either inserting the results into a SQlite database or displaying them in a ListView. (my relevant methods are accepting ArrayList<resourceClass> as arguments). (some data need to be persistent stored and some should not). since I don't know what size of lists I can handle this way without reaching the memory limits, is this a good practice ? is it a better idea to save the parsed JSON to a local file immediately and pass the file path to the ResultReceiver, then either insert to database from that file or display the data ? is there a better way to handle this ? btw - I'm parsing the JSON as a stream with Gson's Reader so there shouldn't be memory issues at that stage.

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  • boost::python string-convertible properties

    - by Checkers
    I have a C++ class, which has the following methods: class Bar { ... const Foo& getFoo() const; void setFoo(const Foo&); }; where class Foo is convertible to std::string (it has an implicit constructor from std::string and an std::string cast operator). I define a Boost.Python wrapper class, which, among other things, defines a property based on previous two functions: class_<Bar>("Bar") ... .add_property( "foo", make_function( &Bar::getFoo, return_value_policy<return_by_value>()), &Bar::setFoo) ... I also mark the class as convertible to/from std::string. implicitly_convertible<std::string, Foo>(); implicitly_convertible<Foo, std::string>(); But at runtime I still get a conversion error trying to access this property: TypeError: No to_python (by-value) converter found for C++ type: Foo How to achieve the conversion without too much boilerplate of wrapper functions? (I already have all the conversion functions in class Foo, so duplication is undesirable.

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  • How can I diff against a revision of a single file using only the default Git GUI tools?

    - by Rich
    I want to view the history of a single file, and then compare a single revision from that history against the current version. On the command line, this is easy: Run: git log -- <filename> Locate the version you want to compare, Run: git diff <commitid> -- <filename> But how can this be done using only the default Git gui tools, git gui and gitk? I know of two methods using gitk, but they're both horribly clunky: Either: Select the New View option from the View menu, Type in the full path to your file into the box labelled Enter files and directories to include, one per line, Locate the version you want to compare by looking at the highlighted items in the top pane, and click on it to select it, Right-click on the current version and select Diff selected - this, Or: Select Tree in the bottom right-hand pane, Locate the file you want to look at, right-click on it, and select Highlight this only, Locate the version you want to compare by looking at the highlighted items in the top pane, and click on it to select it, Right-click on the current version and select Diff selected - this, Click on the file in the bottom right-hand pane to jump to it in the diff output, or scroll manually. Is a better method than this?

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  • Python and the self parameter

    - by Svend
    I'm having some issues with the self parameter, and some seemingly inconsistent behavior in Python is annoying me, so I figure I better ask some people in the know. I have a class, Foo. This class will have a bunch of methods, m1, through mN. For some of these, I will use a standard definition, like in the case of m1 below. But for others, it's more convinient to just assign the method name directly, like I've done with m2 and m3. import os def myfun(x, y): return x + y class Foo(): def m1(self, y, z): return y + z + 42 m2 = os.access m3 = myfun f = Foo() print f.m1(1, 2) print f.m2("/", os.R_OK) print f.m3(3, 4) Now, I know that os.access does not take a self parameter (seemingly). And it still has no issues with this type of assignment. However, I cannot do the same for my own modules (imagine myfun defined off in mymodule.myfun). Running the above code yields the following output: 3 True Traceback (most recent call last): File "foo.py", line 16, in <module> print f.m3(3, 4) TypeError: myfun() takes exactly 2 arguments (3 given) The problem is that, due to the framework I work in, I cannot avoid having a class Foo at least. But I'd like to avoid having my mymodule stuff in a dummy class. In order to do this, I need to do something ala def m3(self,a1, a2): return mymodule.myfun(a1,a2) Which is hugely redundant when you have like 20 of them. So, the question is, either how do I do this in a totally different and obviously much smarter way, or how can I make my own modules behave like the built-in ones, so it does not complain about receiving 1 argument too many.

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  • Can't log in with a valid password using Authlogic and Ruby on Rails?

    - by kbighorse
    We support a bit of an unusual scheme. We don't require a password on User creation, and use password_resets to add a password to the user later, on demand. The problem is, once a password is created, the console indicates the password is valid: user.valid_password? 'test' = true but in my UserSessions controller, @user_session.save returns false using the same password. What am I not seeing? Kimball UPDATE: Providing more details, here is the output when saving the new password: Processing PasswordResetsController#update (for 127.0.0.1 at 2011-01-31 14:01:12) [PUT] Parameters: {"commit"="Update password", "action"="update", "_method"="put", "authenticity_token"="PQD4+eIREKBfHR3/fleWuQSEtZd7RIvl7khSYo5eXe0=", "id"="v3iWW5eD9P9frbEQDvxp", "controller"="password_resets", "user"={"password"="johnwayne"}} The applicable SQL is: UPDATE users SET updated_at = '2011-01-31 22:01:12', crypted_password = 'blah', perishable_token = 'blah', password_salt = 'blah', persistence_token = 'blah' WHERE id = 580 I don't see an error per se, @user_session.save just returns false, as if the password didn't match. I skip validating passwords in the User model: class User < ActiveRecord::Base acts_as_authentic do |c| c.validate_password_field = false end Here's the simplified controller code: def create logger.info("SAVED SESSION? #{@user_session.save}") end which outputs: Processing UserSessionsController#create (for 127.0.0.1 at 2011-01-31 14:16:59) [POST] Parameters: {"commit"="Login", "user_session"={"remember_me"="0", "password"="johnwayne", "email"="[email protected]"}, "action"="create", "authenticity_token"="PQD4+eIREKBfHR3/fleWuQSEtZd7RIvl7khSYo5eXe0=", "controller"="user_sessions"} User Columns (2.2ms) SHOW FIELDS FROM users User Load (3.7ms) SELECT * FROM users WHERE (users.email = '[email protected]') ORDER BY email ASC LIMIT 1 SAVED SESSION? false CACHE (0.0ms) SELECT * FROM users WHERE (users.email = '[email protected]') ORDER BY email ASC LIMIT 1 Redirected to http://localhost:3000/login Lastly, the console indicates that the new password is valid: $ u.valid_password? 'johnwayne' = true Would love to do it all in the console, is there a way to load UserSession controller and call methods directly? Kimball

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  • How to implement a 'safe' periodical executer without using the Rails helpers?

    - by Robbie
    I am very new to Ruby on Rails and was never really big on writing JavaScript, so the built in helpers were like a tiny silce of heaven. However I have recently learned that using the helper methods creates "obtrusive javascript" so I am doing a tiny bit of refactoring to get all this messy code out of my view. I'm also using the Prototype API to figure out what all these functions do. Right now, I have: <%= periodically_call_remote(:url => {:action => "tablerefresh", :id => 1 }, :frequency => '5', :complete => "load('26', 'table1', request.responseText)")%> Which produces: <script type="text/javascript"> //<![CDATA[ new PeriodicalExecuter(function() {new Ajax.Request('/qrpsdrail/grids/tablerefresh/1', {asynchronous:true, evalScripts:true, onComplete:function(request){load('26', 'table1', request.responseText)}, parameters:'authenticity_token=' + encodeURIComponent('dfG7wWyVYEpelfdZvBWk7MlhzZoK7VvtT/HDi3w7gPM=')})}, 5) //]]> </script> My concern is that the "encodeURIComponent" and the presence of "authenticity_token" are generated by Rails. I'm assuming these are used to assure the validity of a request. (Ensuring a request comes from a currently active session?) If that is the case, how can I implement this in application.js 'safely'? It seems that the built in method, although obtrusive, does add some beneficial security. Thanks, in advance, to all who answer.

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  • Ruby TypeErrors involving `expected Data`

    - by Kenny Peng
    I've ran into situations where I have gotten these expected Data errors before, but they have always pointed to ActiveRecord not playing well with other libraries in the past. This piece of code: def load(kv_block, debug=false) # Converts a string block to a Hash using split kv_map = StringUtils.kv_array_to_hash(kv_block) # Loop through each key, value kv_map.each do |mem,val| # Format the member from camel case to underscore member = mem.camel_to_underscore() # If the object includes a method to set the key (i.e. the key # is a member of self), invoke the method, setting the value of # the member) if self.methods.include?(member.to_set_method_name()) then # Exception thrown here self.send(member.to_set_method_name(), val) # Else, check for the same case, this time for an instance variable elsif self.instance_variable_defined?(member.to_instance_var_name()) self.instance_variable_set(member.to_instance_var_name(), val) # Else, complain that the object doesn't understand the key with # respect to its class definition. else raise ArgumentError, "I don't know what to do with #{member}. #{self.class} does not have a member or function called #{member}" end end end produces the error wrong argument type #<Class:0x11a02088> (expected Data) (TypeError) in the each loop on the first if test. I've inspected a post-mortem debugging instance using rdebug, and running that line manually, it works without a hitch. Has anyone seen this error before and what's been your solution to it? I used to think it was ActiveRecord and other gems stomping on each other's definitions, but I removed any references to ActiveRecord and this still occurs.

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  • How to enforce users to create objects of class derived from mine with "new" only?

    - by sharptooth
    To implement reference counting we use an IUnknown-like interface and a smart pointer template class. The interface has implementation for all the reference-count methods, including Release(): void IUnknownLike::Release() { if( --refCount == 0 ) { delete this; } } The smart pointer template class has a copy constructor and an assignment operator both accepting raw pointers. So users can do the following: class Class : public IUnknownLike { }; void someFunction( CSmartPointer<Class> object ); //whatever function Class object; someFunction( &object ); and the program runs into undefined behavior - the object is created with reference count zero, the smart pointer is constructed and bumps it to one, then the function returns, smart pointer is destroyed, calls Release() which leads to delete of a stack-allocated variable. Users can as well do the following: struct COuter { //whatever else; Class inner;// IUnknownLike descendant }; COuter object; somefunction( &object.Inner ); and again an object not created with new is deleted. Undefined behavior at its best. Is there any way to change the IUnknownLike interface so that the user is forced to use new for creating all objects derived from IUnknownLike - both directly derived and indirectly derived (with classes in between the most derived and the base)?

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  • Componentizing complex functionality in an MVC web app

    - by NXT
    Hi Everyone, This is question about MVC web-app architecture, and how it can be extended to handle componentizing moderately complex units of functionality. I have an MVC style web-app with a customer facing credit card charge page. I've been asked to allow the admins to enter credit card payments as well, for times when credit cards are taken over the phone. The customer facing credit card charge section of the website is currently it's own controller, with approximately 3 pages and a login. That controller is responsible for: Customer login credential authentication Credit card data collection Calling a library to do the actual charge. reporting the results to the user. I would like to extract the card data collection pages into a component of some kind so that I can easily reuse the code on the admin side of the app. Right now my components are limited to single "view" pages with PHP style embedded Perl code. This is a simple, custom MVC framework written in Perl. Right now, controllers are called directly from the framework to service web requests. My idea is to allow controllers to be called from other controllers, so that I can componentize more complex functionality. For simplicity I think I prefer composition over inheritance, even though it will require writing a bunch of pass-through methods (actions). Being Perl, I could in theory do multiple inheritance. I'm wondering if anyone with experience in other MVC web frameworks can comment on how this sort of thing is usually done. Thank you.

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  • php error reporting - having trouble matching local & web server settings

    - by Andrew Heath
    I'm trying to add a custom error handler to my site, but in doing so have discovered that my webhost's PHP error reporting settings and those of my localhost (default XAMPP) vary considerably. While I thought I was programming to E_STRICT like a good little boy, adding the error handler to my webhost revealed craploads of Runtime Notices. Example: Runtime notice strtotime() [function.strtotime]: It is not safe to rely on the system's timezone settings. Please use the date.timezone setting, the TZ environment variable or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/Chicago' for 'CST/-6.0/no DST' instead In /home/... Clearly this isn't a red-alert, showstopping error. But what bothers me is that it doesn't show up on my localhost. I'd certainly like to improve my code by addressing these sorts of issues if I could see them! I've looked through both php.ini files, and my webhost's setting is error_reporting = E_ALL & ~E_NOTICE whereas mine was error_reporting = E_STRICT, which I had thought was better. However, changing mine to match and rebooting the server doesn't seem to have accomplished anything. Could someone please point me in the right direction?

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  • C# - Advantages/Disadvantages of different implementations for Comparing Objects

    - by Kevin Crowell
    This questions involves 2 different implementations of essentially the same code. First, using delegate to create a Comparison method that can be used as a parameter when sorting a collection of objects: class Foo { public static Comparison<Foo> BarComparison = delegate(Foo foo1, Foo foo2) { return foo1.Bar.CompareTo(foo2.Bar); }; } I use the above when I want to have a way of sorting a collection of Foo objects in a different way than my CompareTo function offers. For example: List<Foo> fooList = new List<Foo>(); fooList.Sort(BarComparison); Second, using IComparer: public class BarComparer : IComparer<Foo> { public int Compare(Foo foo1, Foo foo2) { return foo1.Bar.CompareTo(foo2.Bar); } } I use the above when I want to do a binary search for a Foo object in a collection of Foo objects. For example: BarComparer comparer = new BarComparer(); List<Foo> fooList = new List<Foo>(); Foo foo = new Foo(); int index = fooList.BinarySearch(foo, comparer); My questions are: What are the advantages and disadvantages of each of these implementations? What are some more ways to take advantage of each of these implementations? Is there a way to combine these implementations in such a way that I do not need to duplicate the code? Can I achieve both a binary search and an alternative collection sort using only 1 of these methods?

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  • How to retrieve view of MultiIndex DataFrame

    - by Henry S. Harrison
    This question was inspired by this question. I had the same problem, updating a MultiIndex DataFrame by selection. The drop_level=False solution in Pandas 0.13 will allow me to achieve the same result, but I am still wondering why I cannot get a view from the MultiIndex DataFrame. In other words, why does this not work?: >>> sat = d.xs('sat', level='day', copy=False) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\Python27\lib\site-packages\pandas\core\frame.py", line 2248, in xs raise ValueError('Cannot retrieve view (copy=False)') ValueError: Cannot retrieve view (copy=False) Of course it could be only because it is not implemented, but is there a reason? Is it somehow ambiguous or impossible to implement? Returning a view is more intuitive to me than returning a copy then later updating the original. I looked through the source and it seems this situation is checked explicitly to raise an error. Alternatively, is it possible to get the same sort of view from any of the other indexing methods? I've experimented but have not been successful. [edit] Some potential implementations are discussed here. I guess with the last question above I'm wondering what the current best solution is to index into arbitrary multiindex slices and cross-sections.

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  • what use does the javascript forEach method have (that map can't do)?

    - by JohnMerlino
    Hey all, The only difference I see in map and foreach is that map is returning an array and foreach is not. However, I don't even understand the last line of the foreach method "func.call(scope, this[i], i, this);". For example, isn't "this" and "scope" referring to same object and isn't this[i] and i referring to the current value in the loop? I noticed on another post someone said "Use forEach when you want to do something on the basis of each element of the list. You might be adding things to the page, for example. Essentially, it's great for when you want "side effects". I don't know what is meant by side effects. Array.prototype.map = function(fnc) { var a = new Array(this.length); for (var i = 0; i < this.length; i++) { a[i] = fnc(this[i]); } return a; } Array.prototype.forEach = function(func, scope) { scope = scope || this; for (var i = 0, l = this.length; i < l; i++) func.call(scope, this[i], i, this); } Finally, are there any real uses for these methods in javascript (since we aren't updating a database) other than to manipulate numbers like this: alert([1,2,3,4].map(function(x){ return x + 1})); //this is the only example I ever see of map in javascript. Thanks for any reply.

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  • How to change button background color depending on bound command canexecute ??

    - by LaurentH
    Hi, I Have a ItemTemplate in which is a simple button bound on a command, which can be executable or not depending on some property. I'd like the color of this button's background to change if the command isn't executable. I tried several methods, but I can't find anyway to do this purely in XAML (I'm doing this in a study context, and code behind isn't allowed). Here's my code for the button : <Button x:Name="Dispo" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center" Width="30" Height="30" Grid.Column="2" Grid.Row="0" Command="{Binding AddEmpruntCommandModel.Command}" CommandParameter="{Binding ElementName='flowCars', Path='SelectedItem'}" vm:CreateCommandBinding.Command="{Binding AddEmpruntCommandModel}" > <Button.Style> <Style TargetType="{x:Type Button}"> <Style.Triggers> <Trigger Property="IsEnabled" Value="True"> <Setter Property="Button.Background" Value="Green"/> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter Property="Button.Background" Value="Red"/> </Trigger> </Style.Triggers> </Style> </Button.Style> </Button>

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  • How do I call an Obj-C method from Javascript?

    - by gnfti
    Hi all, I'm developing a native iPhone app using Phonegap, so everything is done in HTML and JS. I am using the Flurry SDK for analytics and want to use the [FlurryAPI logEvent:@"EVENT_NAME"]; method to track events. Is there a way to do this in Javascript? So when tracking a link I would imagine using something like <a onClick="flurryTrackEvent("Click_Rainbows")" href="#Rainbows">Rainbows</a> <a onClick="flurryTrackEvent("Click_Unicorns")" href="#Unicorns">Unicorns</a> "FlurryAPI.h" has the following: @interface FlurryAPI : NSObject { } + (void)startSession:(NSString *)apiKey; + (void)logEvent:(NSString *)eventName; + (void)logEvent:(NSString *)eventName withParameters:(NSDictionary *)parameters; + (void)logError:(NSString *)errorID message:(NSString *)message exception:(NSException *)exception; + (void)setUserID:(NSString *)userID; + (void)setEventLoggingEnabled:(BOOL)value; + (void)setServerURL:(NSString *)url; + (void)setSessionReportsOnCloseEnabled:(BOOL)sendSessionReportsOnClose; @end I'm only interested in the logEvent method(s). If it's not clear by now, I'm comfortable with JS but a recovering Obj-C noob. I've read the Apple docs but the examples described there are all for newly declared methods and I imagine this could be simpler to implement because the Obj-C method(s) are already defined. Thank you in advance for any input.

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  • Obj-C: Passing pointers to initialized classes in other classes

    - by FnGreg7
    Hey all. I initialized a class in my singleton called DataModel. Now, from my UIViewController, when I click a button, I have a method that is trying to access that class so that I may add an object to one of its dictionaries. My get/set method passes back the pointer to the class from my singleton, but when I am back in my UIViewController, the class passed back doesn't respond to methods. It's like it's just not there. I think it has something to do with the difference in passing pointers around classes or something. I even tried using the copy method to throw a copy back, but no luck. UIViewController: ApplicationSingleton *applicationSingleton = [[ApplicationSingleton alloc] init]; DataModel *dataModel = [applicationSingleton getDataModel]; [dataModel retrieveDataCategory:dataCategory]; Singleton: ApplicationSingleton *m_instance; DataModel *m_dataModel; - (id) init { NSLog(@"ApplicationSingleton.m initialized."); self = [super init]; if(self != nil) { if(m_instance != nil) { return m_instance; } NSLog(@"Initializing the application singleton."); m_instance = self; m_dataModel = [[DataModel alloc] init]; } NSLog(@"ApplicationSingleton init method returning."); return m_instance; } -(DataModel *)getDataModel { DataModel *dataModel_COPY = [m_dataModel copy]; return dataModel_COPY; } For the getDataModel method, I also tried this: -(DataModel *)getDataModel { return m_dataModel; } In my DataModel retrieveDataCategory method, I couldn't get anything to work. I even just tried putting a NSLog in there but it never would come onto the console. Any ideas?

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  • ASP.NET AJAX weirdness

    - by LoveMeSomeCode
    Ok, I thought I understood these topics well, but I guess not, so hopefully someone here can clear this up. Page.IsAsync seems to be broken. It always returns false. But ScriptManager.IsInAsyncPostBack seems to work, sort of. It returns true during the round trip for controls inside UpdatePanels. This is good; I can tell if it's a partial postback or a regular one. ScriptManager.IsInAsyncPostBack returns false however for async Page Methods. Why is this? It's not a regular postback, I'm just calling a public static method on the page. It causes a problem because I also realized that if you have a control with AutoPostBack = false, it won't trigger a postback on it's own, but if it has an event handler on the page, that event handler code WILL run on the next postback, regardless of how the postback occurred, IF the value has changed. i.e. if I tweak a dropdown and then hit a button, that dropdown's handler code will fire. This is ok, except that it will also happen during Page Method calls, and I have no way to know the difference. Any thoughts?

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  • Learning libraries without books or tutorials

    - by Kawili-wili
    While many ask questions about where to find good books or tutorials, I'd like to take the opposite tack. I consider myself to be an entry-level programmer ready to move up to mid-level. I have written code in c, c++, c#, perl, python, clojure, vb, and java, so I'm not completely clueless. Where I see a problem in moving to the next level is learning to make better use of the literally hundreds upon hundreds of libraries available out there. I seem paralyzed unless there is a specific example in a book or tutorial to hand-hold me, yet I often read in various forums where another programmer attempts to assist with a question. He/she will look through the docs or scan the available classes/methods in their favorite IDE and seem to grok what's going on in a relatively short period of time, even if they had no previous experience with that specific library or function. I yearn to break the umbilical chord of constantly spending hour upon hour searching and reading, searching and reading, searching and reading. Many times there is no book or tutorial, or if there is, the discussion glosses over my specific needs or the examples shown are too far off the path for the usage I had in mind or the information is outdated and makes use of deprecated components or the library itself has fallen out of mainstream, yet is still perfectly usable (but no docs, books, or tutorials to hand-hold). My question is: In the absence of books or tutorials, what is the best way to grok new or unfamiliar libraries? I yearn to slicken the grok path so I can get down to the business of doing what I love most -- coding.

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  • Ruby and public_method_defined? : strange behaviour

    - by aXon
    Hi there Whilst reading through the book "The well grounded Rubyist", I came across some strange behaviour. The idea behind the code is using one's own method_missing method. The only thing I am not able to grasp is, why this code gets executed, as I do not have any Person.all_with_* class methods defined, which in turn means that the self.public_method_defined?(attr) returns true (attr is friends and then hobbies). #!/usr/bin/env ruby1.9 class Person PEOPLE = [] attr_reader :name, :hobbies, :friends def initialize(mame) @name = name @hobbies = [] @friends = [] PEOPLE << self end def has_hobby(hobby) @hobbies << hobby end def has_friend(friend) @friends << friend end def self.method_missing(m,*args) method = m.to_s if method.start_with?("all_with_") attr = method[9..-1] if self.public_method_defined?(attr) PEOPLE.find_all do |person| person.send(attr).include?(args[0]) end else raise ArgumentError, "Can't find #{attr}" end else super end end end j = Person.new("John") p = Person.new("Paul") g = Person.new("George") r = Person.new("Ringo") j.has_friend(p) j.has_friend(g) g.has_friend(p) r.has_hobby("rings") Person.all_with_friends(p).each do |person| puts "#{person.name} is friends with #{p.name}" end Person.all_with_hobbies("rings").each do |person| puts "#{person.name} is into rings" end The output is is friends with is friends with is into rings which is really understandable, as there is nothing to be executed.

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