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  • t-sql get variable value from string with variable name

    - by Markus
    Hi. Is there a way to convert '@my_variable' string into a value of @my_variable? I have a table which stores names of variables. I need to get the value of this variable. Something like this: DECLARE @second_variable AS NVARCHAR(20); DECLARE @first_variable AS NVARCHAR(20); SET @first_variable = '20'; SET @second_variable = SELECT '@first_variable'; --here I want that @second variable be assigned a value of "20".

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  • How can I stop cURL from outputting the contents of the page it loads into the browser?

    - by Rob
    I currently use curl_multi_* to connect to a few sites. Its only sending a few $_GET variables to start a script, but it outputs the html from the sites to the browser. I want to stop this. I already use a short timeout, but sometimes the scripts start fast, and I don't want to set the timeout any lower, in case it causes it not to connect. So how can I stop the output to the browser from cURL?

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  • With ARC why use @properties anymore?

    - by trapper
    In non-ARC code retained properties handily take care of memory management for you using the self.property = syntax, so we were taught to use them for practically everything. But now with ARC this memory management is no longer an issue, so does the reason for using properties evaporate? is there still any good reason (obviously other than providing public access to instance variables) to use properties anymore?

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  • simplify expression k/m%n

    - by aaa
    hello. Simple question, is it possible to simplify (or replace division or modulo by less-expensive operation) (k/m)%n where variables are integers and operators are C style division and modulo operators. what about the case where m and n are constants (both or just one), not based 2? Thank you

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  • why do I need the @ for setting variable value

    - by Saad
    I'm a little confused about scope of variables, in ruby I wrote a test program: class Test attr_reader :tester def initialize(data) @tester = data end def getData tester end end puts Test.new(11).getData now this works fine, the attr_reader, but my confusion is that since I've define attr_reader :tester then why can't I go tester = data rather then @tester = data, because when retrieving the data in getData I only have to write tester and not @tester

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  • Reusing a NSString variable - does it cause a memory leak?

    - by Chris S
    Coming from a .NET background I'm use to reusing string variables for storage, so is the code below likely to cause a memory leak? The code is targeting OS X on the iphone/itouch so no automatic GC. -(NSString*) stringExample { NSString *result = @"example"; result = [result stringByAppendingString:@" test"]; // where does "example" go? return result; } What confuses me is an NSStrings are immutable, but you can reuse an 'immutable' variable with no problem.

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  • Flash Builder 4 debug issue

    - by Tempname
    I am trying to debug an application in Flash Builder 4. The application I am working makes use of php session variables to ensure that the user is logged in. When not debugging, after logging in I can simply path to the container html file and everything works fine. However, when I am debugging a new IE window is launched but for some odd reason the previously logged in php session does not exist for this window. Is this an issue with IE?

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  • Which is the correct way to use PDO in PHP?

    - by Runner
    One from here: $sth->execute(array(':calories' => $calories, ':colour' => $colour)); The other from here: /*** reassign the variables again ***/ $data = array('animal_id'=>4, 'animal_name' => 'bruce'); /*** execute the prepared statement ***/ $stmt->execute($data); My question is: :key or key ? Sorry I don't have the PHP environment here.

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  • Refactoring Singleton Overuse

    - by drharris
    Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

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  • Dubugging a program not run within the debugger and without a crash

    - by Mick
    I left a program running last night, it worked fine for about 5 hours and then one of its built-in self-diagnostic tests detected a problem and brought up a dialog box telling me the issue. The program was built with debug information (/Zi). Is it possible to somehow get the debugger started so I can examine the value of some variables within the program? Or is it too late?

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  • accessing Ruby variable(from model or controller) in SASS

    - by corroded
    Is there a way to access ruby variables in sass or do i have to make a custom function for it? What im trying to do is to generate a stylesheet for each user so in the controller, i do something like: def show respond_to do |format| format.css{render :partial => "styles"} end end then in the view name _styles.haml i do this: :sass #header :background url(user.banner.url) is this possible at all?

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  • SDL_GL_SwapBuffers Segfault

    - by RyanG
    I'm getting a segfault that GDB says is coming from SDL_GL_SwapBuffers. However, I can't imagine why. The SDL documentation mentions no specific pre-conditions for calling swapBuffers except that double buffering be allowed. Is this an option I have to turn on while initializing OpenGL or is this a hardware capability thing? My code: http://pastie.org/859721 (Ignore the unused variables, strange comments and other things. I haven't prettied this up at all. :P)

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  • Stored procedures vs. parameter binding

    - by Gagan
    I am using SQL server and ODBC in visual c++ for writing to the database. Currently i am using parameter binding in SQL queries ( as i fill the database with only 5 - 6 queries and same is true for retrieving data). I dont know much about stored procedures and I am wondering how much if any performance increase stored procedures have over parameter binding as in parameter binding we prepare the query only once and just execute it later in the program for diferent set of values of variables.

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  • How to access class member from bison action

    - by yodhevauhe
    I am calling yyparse from a member function. How to access the member variables/function from the bison action. I am currently doing as %{ #include "myclass.h" #include "parse.tab.hh" MyClass *ptr=NULL; void MyClass::evaluate(string expression) { ptr=this; yy_scan_string(expression.c_str()); yyparse(); } %} %% EXPR : EXPR PLUS EXPR { $$ = ptr->memberFunction("+",$1,$3); }

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  • Matlab code works with one version but not the other

    - by user1325655
    I have a code that works in Matlab version R2010a but shows errors in matlab R2008a. I am trying to implement a self organizing fuzzy neural network with extended kalman filter. I have the code running but it only works in matlab version R2010a. It doesn't work with other versions. Any help? Code attach function [ c, sigma , W_output ] = SOFNN( X, d, Kd ) %SOFNN Self-Organizing Fuzzy Neural Networks %Input Parameters % X(r,n) - rth traning data from nth observation % d(n) - the desired output of the network (must be a row vector) % Kd(r) - predefined distance threshold for the rth input %Output Parameters % c(IndexInputVariable,IndexNeuron) % sigma(IndexInputVariable,IndexNeuron) % W_output is a vector %Setting up Parameters for SOFNN SigmaZero=4; delta=0.12; threshold=0.1354; k_sigma=1.12; %For more accurate results uncomment the following %format long; %Implementation of a SOFNN model [size_R,size_N]=size(X); %size_R - the number of input variables c=[]; sigma=[]; W_output=[]; u=0; % the number of neurons in the structure Q=[]; O=[]; Psi=[]; for n=1:size_N x=X(:,n); if u==0 % No neuron in the structure? c=x; sigma=SigmaZero*ones(size_R,1); u=1; Psi=GetMePsi(X,c,sigma); [Q,O] = UpdateStructure(X,Psi,d); pT_n=GetMeGreatPsi(x,Psi(n,:))'; else [Q,O,pT_n] = UpdateStructureRecursively(X,Psi,Q,O,d,n); end; KeepSpinning=true; while KeepSpinning %Calculate the error and if-part criteria ae=abs(d(n)-pT_n*O); %approximation error [phi,~]=GetMePhi(x,c,sigma); [maxphi,maxindex]=max(phi); % maxindex refers to the neuron's index if ae>delta if maxphi<threshold %enlarge width [minsigma,minindex]=min(sigma(:,maxindex)); sigma(minindex,maxindex)=k_sigma*minsigma; Psi=GetMePsi(X,c,sigma); [Q,O] = UpdateStructure(X,Psi,d); pT_n=GetMeGreatPsi(x,Psi(n,:))'; else %Add a new neuron and update structure ctemp=[]; sigmatemp=[]; dist=0; for r=1:size_R dist=abs(x(r)-c(r,1)); distIndex=1; for j=2:u if abs(x(r)-c(r,j))<dist distIndex=j; dist=abs(x(r)-c(r,j)); end; end; if dist<=Kd(r) ctemp=[ctemp; c(r,distIndex)]; sigmatemp=[sigmatemp ; sigma(r,distIndex)]; else ctemp=[ctemp; x(r)]; sigmatemp=[sigmatemp ; dist]; end; end; c=[c ctemp]; sigma=[sigma sigmatemp]; Psi=GetMePsi(X,c,sigma); [Q,O] = UpdateStructure(X,Psi,d); KeepSpinning=false; u=u+1; end; else if maxphi<threshold %enlarge width [minsigma,minindex]=min(sigma(:,maxindex)); sigma(minindex,maxindex)=k_sigma*minsigma; Psi=GetMePsi(X,c,sigma); [Q,O] = UpdateStructure(X,Psi,d); pT_n=GetMeGreatPsi(x,Psi(n,:))'; else %Do nothing and exit the while KeepSpinning=false; end; end; end; end; W_output=O; end function [Q_next, O_next,pT_n] = UpdateStructureRecursively(X,Psi,Q,O,d,n) %O=O(t-1) O_next=O(t) p_n=GetMeGreatPsi(X(:,n),Psi(n,:)); pT_n=p_n'; ee=abs(d(n)-pT_n*O); %|e(t)| temp=1+pT_n*Q*p_n; ae=abs(ee/temp); if ee>=ae L=Q*p_n*(temp)^(-1); Q_next=(eye(length(Q))-L*pT_n)*Q; O_next=O + L*ee; else Q_next=eye(length(Q))*Q; O_next=O; end; end function [ Q , O ] = UpdateStructure(X,Psi,d) GreatPsiBig = GetMeGreatPsi(X,Psi); %M=u*(r+1) %n - the number of observations [M,~]=size(GreatPsiBig); %Others Ways of getting Q=[P^T(t)*P(t)]^-1 %************************************************************************** %opts.SYM = true; %Q = linsolve(GreatPsiBig*GreatPsiBig',eye(M),opts); % %Q = inv(GreatPsiBig*GreatPsiBig'); %Q = pinv(GreatPsiBig*GreatPsiBig'); %************************************************************************** Y=GreatPsiBig\eye(M); Q=GreatPsiBig'\Y; O=Q*GreatPsiBig*d'; end %This function works too with x % (X=X and Psi is a Matrix) - Gets you the whole GreatPsi % (X=x and Psi is the row related to x) - Gets you just the column related with the observation function [GreatPsi] = GetMeGreatPsi(X,Psi) %Psi - In a row you go through the neurons and in a column you go through number of %observations **** Psi(#obs,IndexNeuron) **** GreatPsi=[]; [N,U]=size(Psi); for n=1:N x=X(:,n); GreatPsiCol=[]; for u=1:U GreatPsiCol=[ GreatPsiCol ; Psi(n,u)*[1; x] ]; end; GreatPsi=[GreatPsi GreatPsiCol]; end; end function [phi, SumPhi]=GetMePhi(x,c,sigma) [r,u]=size(c); %u - the number of neurons in the structure %r - the number of input variables phi=[]; SumPhi=0; for j=1:u % moving through the neurons S=0; for i=1:r % moving through the input variables S = S + ((x(i) - c(i,j))^2) / (2*sigma(i,j)^2); end; phi = [phi exp(-S)]; SumPhi = SumPhi + phi(j); %phi(u)=exp(-S) end; end %This function works too with x, it will give you the row related to x function [Psi] = GetMePsi(X,c,sigma) [~,u]=size(c); [~,size_N]=size(X); %u - the number of neurons in the structure %size_N - the number of observations Psi=[]; for n=1:size_N [phi, SumPhi]=GetMePhi(X(:,n),c,sigma); PsiTemp=[]; for j=1:u %PsiTemp is a row vector ex: [1 2 3] PsiTemp(j)=phi(j)/SumPhi; end; Psi=[Psi; PsiTemp]; %Psi - In a row you go through the neurons and in a column you go through number of %observations **** Psi(#obs,IndexNeuron) **** end; end

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  • c# Tuple - What is a practical use of Tuple [duplicate]

    - by Nate Pet
    This question already has an answer here: What and When to use Tuple? 5 answers I was looking at examples online of Tuple but I do not see any ideal use of it. Meaning, it seems like a place to store variables. Is there any practical use of Tuple. What I like to do is to pass in a value to the tuple and then have it return back 3 values which are all strings.

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  • best articles about organizing code files in C

    - by kliketa
    Can you recommend me what should I read/learn in order to make a well organized code in C? One of the things I want to learn is the principles of splitting project in .h and .c files, what goes where and why, variable naming, when to use global variables ... I am interested in books and articles that deal with this specific problem.

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  • where can I find the rake tasks delivered with rails

    - by ash34
    I am looking for tasks like tmp:clear or db:migrate. Where can I find the code for these tasks. I remember seeing them before but don't recollect where. Also, is there a way I can set some global variables in a .rake file that can be accessed by all tasks in that file without passing them as arguments to each task. thanks, ash

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  • OnTaskFailed event handler in SSIS

    - by Jason M
    If I use OnError event handler in my SSIS package, there are variables System::ErrorCode and System::ErrorDescription from which I can get the error information if any things fails while execution. But I cant the find the same for OnTaskFailed event handler, i.e. How to get the ErrorCode and ErrorDescription from the OnTaskFailed event handler when any things fails while execution in case we want to only implement OnTaskFailed event handler for our package?

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  • Execute something on application startup?

    - by Nick Brooks
    I have a class in my application which handles all the controls and all the functions and variables are stored in it. How can I add a function which handles the application startup to it? So basically I need to handle 'applicationDidFinishLaunching' in my class as well as in the application delegate. How do I do that?

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