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• How to store and retrieve file in mongoengine?

  - by Seiverence

  I am attempting to store and retrieve file within mongodb, but am having issues with the retrieval. class Animal(Document): genus = StringField() family = StringField() photo = FileField() def get_file(): marmot = Animal.objects(genus='Marmota').first() photo = marmot.photo.read() content_type = marmot.photo.content_type print marmot.family # Prints out "Sciuridae" print content_type # Gives me an error, as content_type is "None" def save_file(): marmot = Animal( genus='Marmota', family='Sciuridae') marmot_photo = open('marmot.jpg', 'r') marmot.photo = marmot_photo marmot.photo.content_type = 'image/jpeg' marmot.save() When I check mongodb, it appears the document does save after the save_file, but when I call get_file, it appears the content_type is "None"? Am I saving and retrieving the file correctly? If not, whats wrong with the code? NOTE: The issue appears only to occur in the Windows environment. When run on linux, it works fine... very confused.

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• Accessing local variable doesn't improve performance

  - by NicMagnier

  The short version Why is this code: var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; More performant than this one? var index = Math.floor(ref_index) * 4; The long version This week, the author of Impact js published an article about some rendering issue: http://www.phoboslab.org/log/2012/09/drawing-pixels-is-hard In the article there was the source of a function to scale an image by accessing pixels in the canvas. I wanted to suggest some traditional ways to optimize this kind of code so that the scaling would be shorter at loading time. But after testing it my result was most of the time worst that the original function. Guessing this was the JavaScript engine that was doing some smart optimization I tried to understand a bit more what was going on so I did a bunch of test. But my results are quite confusing and I would need some help to understand what's going on. I have a test page here: http://www.mx981.com/stuff/resize_bench/test.html jsPerf: http://jsperf.com/local-variable-due-to-the-scope-lookup To start the test, click the picture and the results will appear in the console. There are three different versions: The original code: for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; var indexScaled = (y * widthScaled + x) * 4; scaledPixels.data[ indexScaled ] = origPixels.data[ index ]; scaledPixels.data[ indexScaled+1 ] = origPixels.data[ index+1 ]; scaledPixels.data[ indexScaled+2 ] = origPixels.data[ index+2 ]; scaledPixels.data[ indexScaled+3 ] = origPixels.data[ index+3 ]; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance One of my attempt to optimize it: var ref_index = 0; var ref_indexScaled = 0 var ref_step = 1 / scale; for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = Math.floor(ref_index) * 4; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+1 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+2 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+3 ]; ref_index+= ref_step; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance The same optimized code but with recalculating the index variable each time (Hybrid) var ref_index = 0; var ref_indexScaled = 0 var ref_step = 1 / scale; for( var y = 0; y < heightScaled; y++ ) { for( var x = 0; x < widthScaled; x++ ) { var index = (Math.floor(y / scale) * img.width + Math.floor(x / scale)) * 4; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+1 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+2 ]; scaledPixels.data[ ref_indexScaled++ ] = origPixels.data[ index+3 ]; ref_index+= ref_step; } } jsPerf: http://jsperf.com/so-accessing-local-variable-doesn-t-improve-performance The only difference in the two last one is the calculation of the 'index' variable. And to my surprise the optimized version is slower in most browsers (except opera). Results of personal testing (not the jsPerf tests): Opera Original: 8668ms Optimized: 932ms Hybrid: 8696ms Chrome Original: 139ms Optimized: 145ms Hybrid: 136ms Safari Original: 433ms Optimized: 853ms Hybrid: 451ms Firefox Original: 343ms Optimized: 422ms Hybrid: 350ms After digging around, it seems an usual good practice is to access mainly local variable due to the scope lookup. Because The optimized version only call one local variable it should be faster that the Hybrid code which call multiple variable and object in addition to the various operation involved. So why the "optimized" version is slower? I thought that it might be because some JavaScript engine don't optimize the Optimized version because it is not hot enough but after using --trace-opt in chrome, it seems all version are properly compiled by V8. At this point I am a bit clueless and wonder if somebody would know what is going on? I did also some more test cases in this page: http://www.mx981.com/stuff/resize_bench/index.html

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• Qt QMainWindow at Close

  - by Cenoc

  Hey, this may seem like a very simple question, but I want to dump some data whenever the QMainWindow closes, so I used the following piece of code: QObject::connect(MainWindow.centralwidget, SIGNAL(destroyed()), this, SLOT(close())); but this doesnt seem to make it call close(). Am I doing this wrong? Isnt the centralwidget suppose to be destroyed? Or perhaps the application closes before close() can be called? Any other ways of doing it then? Thanks in advance!

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• Use variables entered in login page usable in multiple pages?

  - by deception1

  I have a Login page that captures User input like this. MD5calc ss = new DBCon.MD5calc(); string gs = ss.CalculateMD5Hash(password.Password); int unitID = Convert.ToInt32(Unit_ID.Text); logBO.UnitID = unitID; logBO.UserID = User_name.Text; logBO.UserPass = gs; How would i make them assignable to any other page i created.My Common sense says that creating a static class would be enough,but will it?If i do create a static class where would i put it and how would i call it?I actually need those variable to use in my Sql Stored procedures.

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• In a JDBC ResultSet, what should happen when getLong() or getShort() is called on an int result colu

  - by Uri

  Say that I have a JDBC ResultSet, and I call the getLong() or getshort() method. For which of the following SQL types {SMALLINT, INT, BIGINT} should I get long, and for which types should I get an error? In other words, if I have an INT and I want a SMALLINT (A short), would I get it, or would I get an error? Similarly, if I have an INT and want a BIGINT (a long), would I get it, or would I get an error? The Javadocs (listed below) say nothing. public long getLong(int columnIndex) throws SQLException Retrieves the value of the designated column in the current row of this ResultSet object as a long in the Java programming language. Parameters: columnIndex - the first column is 1, the second is 2, ... Returns: the column value; if the value is SQL NULL, the value returned is 0 Throws: SQLException - if a database access error occurs

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• Complex SQL queries (DELETE)?

  - by Joe

  Hello all, I'm working with three tables, and for simplicity's sake let's call them table A, B, and C. Both tables A and B have a column called id, as well as one other column, Aattribute and Battribute, respectively. Column c also has an id column, and two other columns which hold values for A.id and B.id. Now, in my code, I have easy access to values for both Aattribute and Battribute, and want to delete the row at C, so effectively I want to do something like this: DELETE FROM C WHERE aid=(SELECT id FROM A WHERE Aattribute='myvalue') AND bid=(SELECT id FROM B WHERE Battribute='myothervalue') But this obviously doesn't work. Is there any way to make a single complex query, or do I have to run three queries, where I first get the value of A.id using a SELECT with 'myvalue', then the same for B.id, then use those in the final query? [Edit: it's not letting me comment, so in response to the first comment on this: I tried the above query and it did not work, I figured it just wasn't syntactically correct. Using MS Access, for what it's worth. ]

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• How do I compare a string in an array to a string?

  - by user1641312

  EDIT: IT'S FIXED, THANKS FOR THE HELP! So basically I have an array of strings, a question and an answer public static String[][] triviaData = { {"Question2", "Answer1"}, {"Question2", "Answer2"}, {"Question3", "Answer3"}, }; And I am trying to make a method that validates an entered input, lets call the entered input enteredAnswer. enteredAnswer is stored as a String. I am trying to validate that the enteredAnswer is the same as the second index of the array. if (enteredAnswer.equalsIgnoreCase(triviaData[Config.CurrentQuestion][1])) { This is the code I tried, but I get the error "Cannot invoke equalsIgnoreCase(String) on the array type String[]" I am a beginner programmer so if you could help me out it would be highly appreciated. Thanks. enteredAnswer is stored as public String[] enteredAnswer;

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• Using AttachConsole, user must hit enter to get regular command line.

  - by Clangon

  I have a progaram that can be ran both as a winform, or from command line. If it is invoked from a command line I call AttachConsole(-1) to attach to parent console. However, after my program ends, the user must hit enter to get back the standard command prompt ("c:\"). is there a way to avoid that need? Thanks. I could wrap it in a cmd file to avoid that issue, but I would like to do it from my exe.

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• jQuery extend $.fn and calling method syntax

  - by MBax

  I understand that you call a method like this when you are extending $.fn. ( $ == jQuery ) //$("div").myMethod(); $.fn.extend({ myMethod: function(){...} }); And like this when you extend the jQuery Object: //$.myMethod2(); $.extend({ myMethod2: function(){...} }); But I don't quite understand what the $() is doing here: $().functionName({ something: 'something' }).myMethod(); Does it have to do with the fact the method is being called including the function name? Thanks in advance and hope this makes sense.

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• checkbox dynamic create for jquery

  - by user1397840

  How do i create multiple checkbox for jquery to identify it? example i have a html page with this is call new.html <div id =new> <input type=checkbox"></div> at create.html i want to use jquery to load multiple checkbox <div id=load> <div> $("#load).load(new.html) so if i use a for loop to loop 10times to create 10 checkbox, how do i identify each checkbox uniquely? for(var i = 0;i<10;i++){ $("#load).load(new.html)}

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• date.getHours() to calendar.hour

  - by user1487045

  I want to get the hour of day in 24hour cycle. I know that date.getHours() is depreciated. But I'm tempted to use it since I cant get the same result out of calendar.hour call. Can anyone tell me how to fix what I have below to get the hours out correctly with calendar.hour? ...much appreciated. Date d = new Date(); Calendar c = Calendar.getInstance(); c.setTime(d); System.out.println("hour: "+Math.abs(c.HOUR-24)+", mins: "+Math.abs(c.MINUTE-60)+", d.h: "+d.getHours() +", d.m: "+d.getMinutes());

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• how to use string in va_start?

  - by Newbie

  for some reason, i cant get this working: void examplefunctionname(string str, ...){ ... va_start(ap, str.c_str()); nor do i get this work: void examplefunctionname(string str, ...){ ... int len = str.length(); char *strlol = new char[len+1]; for(int i = 0; i < len; i++){ strlol[i] = str[i]; } strlol[len] = 0; va_start(ap, strlol); but this does: void examplefunctionname(const char *str, ...){ ... va_start(ap, str); could someone show me how i can use string instead of const char * there? its outputting random numbers when i call examplefunctionname("%d %d %d", 1337, 1337, 1337)

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• I'm very new to C# and reading about attributes, is there a keypress attribute?

  - by akevit

  I'm coming from intermediate java level and I wanted to spend some time tonight learning C#, partly because a game I used to play is now free to play (Asheron's Call) and when I used to play I had always wanted to write a plugin for Decal but 10 years ago I didn't know nearly enough to do anything. Anyways most of that won't mean much to anyone, but what I essentially want to do is something along the lines of (psuedo code): [KeyPressEvent("KeyPressed")] private void KeyPressed(object sender, KeyPressEventArgs args) { if (args.KeyPressed == VK_K) { // Do stuff } } If I'm not providing enough information or if my description of what I want to do is a little off base let me know. Most plugins for this are written in VB6, but in the past few years Decal has upgraded to .NET 3.5 support so I can use things up until there; a lot of the VB6 stuff uses event subscriptions (e.g. Core.EchoFilter.ServerDispatch += EchoFilter_ServerDispatch;) My C# vernacular is not up to part, but on that notion I haven't done a whole lot of Java projects that related to events (or Observers as I believe they're referred to as).

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• PHP Passing Data to a Specific Class? (Data Encapsulation)

  - by Adam184

  I've learned that OOP is all about data encapsulation, but what about passing data between classes that have nothing to do with each other (would the below example be worthy of using extends)? class Dog { private $secretVar; public function getSecretVar() { $this->secretVar = 'psst... only for rainbow!'; return $this->secretVar; } } class Rainbow { public function __construct(Dog $Dog) { print_r($Dog->getSecretVar()); } } $Dog = new Dog(); $Rainbow = new Rainbow($Dog); // ... classes that don't need the $secretVar How would you encapsulate $secretVar for only classes Dog and Rainbow? As of now, anyone can call getSecretVar(), and I'm having a hard time allowing that to happen as it seems to defeat the whole point of encapsulation.

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• private virtual function in derived class

  - by user1706047

  class base { public: virtual void doSomething() = 0; }; class derived : public base { **private:** virtual void doSomething(){cout<<"Derived fn"<<endl;} }; now if i do the following: base *b=new child; b->doSomething(); //it calls the derived class fn even if that is private. Question: 1.its able to call the derived class fn even if that is private.How is it possible? Now if i change the inheritance access specifier from public to protected/private then i get compilation error as "'type cast' : conversion from 'Derived *' to 'base *' exists, but is inaccessible" Notes: I am aware on the concepts of the inheritance access specifiers.So in second case as its derived private/protected, its inaccessible. But here it confuses me for the first question. Any input will be highly appreciated

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• How do I get the namespace prefix?

  - by 1.21 gigawatts

  Is there a way to get the namespace prefix from a class or class instance (an object not XML)? For example, in MXML you could declare something as s:Button or local:MyComponent. Is there some call or approach that will return the "s" or "local" value when given the object? For example, if I have the class TextInput and I wanted to show the style inheritance at runtime I could do something like this: s|TextInput { fontFamily:Arial; } s|TextArea#myTextArea { color:red; } local|MyComponent.myBoldStyle { fontWeight: bold; }

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• Windows Batch script - For /L not working -- simple

  - by XoronioX

  need some quick help. This is a university program, everything is working fine except when I call my :forLoop method to iterate through 100 numbers (1,1,100) starting at 1 going by 1 til 100 and doing the iteration % 5 (i%%5). for some reason I cannot get this to work. appreciate any help or direction. When I echo %%A it is iterating through all the number perfect. When I echo %result% I get a blank "" (nothing inside) :forLoop FOR /L %%A IN (1,1,100) DO ( set /A result=%%A %% 2 echo "%%A" echo "%result%" ) Correct code is :forLoop setlocal ENABLEDELAYEDEXPANSION FOR /L %%A IN (1,1,100) DO ( set /A result=%%A %% 5 echo !result! >> results.txt set /A total=!total!+!result! echo !total! )

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• MySQL: Select remaining rows

  - by Bjork24

  I've searched everywhere for this, but I can't seem to find a solution. Perhaps I'm using the wrong terms. Either way, I'm turning to good ol' trusty S.O. to help my find the answer. I have two tables, we'll call them 'tools' and 'installs' tools = id, name, version installs = id, tool_id, user_id The 'tools' table records available tools, which are then installed by a user and recorded in the 'installs' table. Selecting the installed tools are simple enough: SELECT tools.name FROM tools LEFT JOIN installs ON tools.id = installs.tool_id WHERE user_id = 99 ; How do I select the remaining tools -- the ones that have yet to be installed by user #99? I'm sorry if this is painfully obvious, but I just can't seem to figure it out! Thanks for the help!

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• cant figure out pointer assignment in c

  - by vadiklk

  int add(char *var1, char *var2, char **var3) { int num1, num2, length1 = strlen(var1), length2 = strlen(var2), length = max(length1, length2) + 1; char *result = (char*) calloc(length, sizeof(char)); ... free(*var3); *var3 = result; return 0; } out side of the function i get its still nothing(var3); more detail: int addSubCommand(char **vars, int isAdd) { ... return add(vars[index1], var2, &(vars[index3])); } that's where i call add. the char** vars goes from every function to the other.

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• nested has_many

  - by dorelal

  I am using Rails 2.3.5. Class User < ActiveRecord::Base has_many :phones end class Phone < ActiveRecord::Base has_many :frequency_bands end I want to get all the frequency_bands for a user. I know I can write a method def freq_bands for User but I would like to know if it is possible to have has_many freq_bands for a User. In this way I can chain the call. What I would like to have is class User < ActiveRecor::Base has_many :frequence_bands, :through => phones end I think it is possible to have nested has_many using this plugin http://github.com/ianwhite/nested_has_many_through However if possible I would like to avoid using another plugin and rely solely on rails.

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• C# Deserializing to a dictionary<string, Object>

  - by lovecraft

  I'm writing a C#/VB application to connect to a database and do stuff with the data. I was given this code to take a serialized byte array and deserialized it, which is then written to a Dictionary The line of code is: Dictionary<string, Object> DictionaryEmployee = (Dictionary<string, Object> Deserializer(byteArrayEmp)); The errors I'm getting are exceedingly unhelpful. "Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement" if I mouse over Object and "Using the generic type 'System.Collections.Generic.Dictionary' requires 2 type arguments if I mouse over Dictionary.

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• Module.new with class_eval

  - by dorelal

  This is a large commit. But I want you to concentrate on this change block. http://github.com/rails/rails/commit/d916c62cfc7c59ab6411407a05b946d3dd7535e9#L2L1304 Even without understanding the full context of the code I am not able to think of a scenario where I would use include Modue.new { class_eval <<-RUBY def foo puts 'foo' end RUBY } Then end result is that in the root context (self just before include Moduel.new) a method call foo has been added. If I take out the Module.new code and if I only leave class_eval in that case also I will have a method called foo in self. What am I missing.

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• Async Task in a loop

  - by Ankuj

  How does one create an AsyncTask which keeps running itself after a fixed interval of time. For eg. get data from server every 5 minutes and give notification to caller thread that it has received the data. I searched on the forum but could not find much. What I have gathered so far is that 1) A UI thread will call AsyncTask 2) onPrExecute for UI thread access before executing 3) OnPostExecute for UI thread access after executing I dont need to show any progress update to the user. Also, the task will be destroyed when the app closes. Any tutorial for this will he helpful

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• Create Object using ObjectBuilder

  - by dhinesh

  Want to create objects using ObjectBuilder or ObjectBuilder2. I do not want to use StructureMap I was able to create the object having parameterless constructor using the code mentioned below. public class ObjectFactory : BuilderBase<BuilderStage> { public static T BuildUp<T>() { var builder = new Builder(); var locator = new Locator { { typeof(ILifetimeContainer), new LifetimeContainer() } }; var buildUp = builder.BuildUp<T>(locator, null, null); return buildUp; } for creating object of customer you just call ObjectFactory.BuildUp<Customer> However this creates object of class which has no parameters, however I need to create object which are having constructor with parameters.

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• Javascript A thank you page with user name on it

  - by Sarahfromnowhere

  I have a form where a user input name and other contact information. I validate the input and then redirect to a thank you page. I wanted to personalize the page by having the user name appear as part of the thank you note. I tried document.getElementById(Name1).value to retrieve the value of the Name but it it is giving Undefined. Is there a way for me to set the value of the Name1 field to another variable that I call again to include it in my text message?

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