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  • Creating an instance in rails association

    - by Sandeep Rao
    I have three models where a basiccase has a form. Basic case can create a new form. class User < ActiveRecord::Base has_many :basiccases end class Basiccase < ActiveRecord::Base belongs_to :user has_one :basiccases end class Form3C < ActiveRecord::Base belongs_to :basiccases end I want to create an instance of form 3c in the form3c controller. Can any one explain me how I can carry the basiccase_id to the form3c controller to set the foreign key attribute. I can set the value using @basiccase.build_form3_c but I'm not sure how I can get the basiccase_id from the basiccase.

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  • IE 8 Error - What's the cause?

    - by DanCapitanDePlai
    I have two magento eshops that worked perfectly in the past on all major browsers except IE 7. After I installed WINDOWS XP on my computer and accessed my eshops with IE 8, I almost had a heartattack seeing that they aren't working as they should. Before installing Windows XP I was running Windows 7 and the websites were looking good on IE 8. Now, the same IE version, but on different operating systems, gives me headaches! Now, can someone explain me how to 'debug' the ie 8 parsing engine for seeing the errors and try to modify the templates? Thanks.

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  • what is the purpose of numeric/boolean/string objects as opposed to primitive values?

    - by zespri
    In javascript you can call a function as a function or as a constructor. For example you can do : myObject = new Number(13); myPrimitiveValue = Number(13); or simply myPrimitiveValue = 13; I understand the difference between the results. Can you explain me under which reasonable circumstances creating a number, a boolean or a string as an object is desirable? For example, ability to set new properties (this is something you can do on objects but can't really do on primitive values) is almost always a bad idea for objects containing number/boolean/string. Why would I want a numeric/boolean/string object?

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  • the problem of redirecting stdout in c#

    - by Mher
    Could you please explain why the shell redirection doesn't work with System.Diagnostics.Process class? I am trying to redirect the output streams to file with the following snippet: Process p = new Process(); p.StartInfo = new ProcessStartInfo(); p.StartInfo.FileName = "java.exe"; p.StartInfo.Arguments = @"> c:\Temp\test.log 2>&1"; p.StartInfo.UseShellExecute = true; p.Start(); The similar code works without problems with Python. Reading the output streams programmatically doesn't seem a preferable solution in my case because there will be a bunch of processes launched by my application.

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  • Can hash tables really be O(1)

    - by drawnonward
    It seems to be common knowledge that hash tables can achieve O(1) but that has never made sense to me. Can someone please explain it? A. The value is an int smaller than the size of the hash table, so the value is its own hash, so there is no hash table but if there was it would be O(1) and still be inefficient. B. You have to calculate the hash, so the order is O(n) for the size of the data being looked up. The lookup might be O(1) after you do O(n) work, but that still comes out to O(n) in my eyes. And unless you have a perfect hash or a large hash table there are probably several items per bucket so it devolves into a small linear search at some point anyway. I think hash tables are awesome, but I do not get the O(1) designation unless it is just supposed to be theoretical.

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  • ontouch - Switching positions of two views(images) in Android

    - by idish
    I've been looking for that 2 days long and haven't found anything related to it. I'll give an example for my goal. Let's say I have 2 images positioned side by side horizontally. I want the user to be able to switch their positions onlongtouch listener. so let's say that the first image was on the left and the second was on the right side, after switching positions between them, the first image would be in the right and the second would be on the left side. Basically, it is just like in the launcher where you can switch apps positions. Please, if anything is not clear for you, I would like to know, and I'll try to explain it better, thank you.

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  • jquery plugin pattern using jquery.data

    - by web_dev
    I have seen this piece of code in jquery plugin patterns and the notes section mention that we could attach the plugin to the DOM element using the jQuery.data function. What I don't understand is how do I make use of this piece of code. Can somebody provide examples of how to use this functionality and explain its significance? $.fn[pluginName] = function (options) { return $Extend(this).each(function () { if (!$.data(this, 'plugin_' + pluginName)) { $.data(this, 'plugin_' + pluginName, new Plugin( this, options )); } }); };

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  • If I had to create a server farm what should I do? (how others companies work?)

    - by Michel
    I have a business idea but this is not really my field so I'm trying to understand what I'm really dealing with. I have a general understanding of how a web farm works, I'm a web developer and I understand the technology behind it, but I'm curious to know specifically how a web farm is set up and which professionals are involved. Things to consider probably are the hardware, the power supply, the software managment, the cooling system and if possible the usage of green technology/power recycling. Basically, can you explain me how a web hosting company is structured and how it works? A big question, I know, but from what I already read here about the subject a lot of you know this stuff. Thanks for your time guys!

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  • What is the purpose of Process class in Java?

    - by Nitesh Panchal
    Runtime objRuntime = Runtime.getRuntime(); String strBackupString = "mysqldump -u " + userName + " -p" + password + " " + dbName; Process objProcess = objRuntime.exec(strBackupString); This is used for backup of database. But what exactly happens? Can anybody make me explain, what is the purpose of Runtime and Process class? Is this class used to act as if we are typing command from command prompt? Then what should i pass to objRuntime.exec() if i want to open notepad? And is the command executed as soon as we call exec method? If yes, then what purpose does Process serve here? I really can't understand these two classes. Please make me understand. Thanks in advance :)

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  • Counting values in data frame subject to conditions

    - by unixsnob
    I have been searching around and I cannot figure out how to sumarise the data I have in my data frame (subject to some ranges). I know that it can be done when applying some combination of daaply/taaply or table but I haven't been able to get the exact result I was expecting. Basically I want to turn this: part_no val1 val2 val3 2 1 2 3 45.3 2 1 3 4 -12.3 3 1 3 4 99.3 3 1 5 2 -3.2 3 1 4 3 -55.3 Into this: part_no val3_between0_50 val3_bw50_100 val3_bw-50_0 val3_bw-100_-50 2 1 0 0 1 0 3 0 1 0 1 1 This is dummy data, I got a lot more rows, but the idea is the same. I just want to count the number of values for a participant that meet certain condition. If anyone could explain it sort of step by step, I would really appreciate it. I saw lots of different little posts around, but none do exactly this and my attempts only got me half way there. Like using table, etc. Thanks!

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  • Postfix evaluation in C

    - by Andrewziac
    I’m taking a course in C and we have to make a program for the classic Postfix evaluation problem. Now, I’ve already completed this problem in java, so I know that we have to use a stack to push the numbers into, then pop them when we get an operator, I think I’m fine with all of that stuff. The problem I have been having is scanning the postfix expression in C. In java it was easier because you could use charAt and you could use the parseInt command. However, I’m not aware of any similar commands in C. So could anyone explain a method to read each value from a string in the form: 4 9 * 0 - = Where the equals is the signal of the end of the input. Any help would be greatly appreciated and thank you in advance :)

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  • Why people define class, trait, object inside another object in Scala?

    - by Zwcat
    Ok, I'll explain why I ask this question. I begin to read Lift 2.2 source code these days. In Lift, I found that, define inner class and inner trait are very heavily used. object Menu has 2 inner traits and 4 inner classes. object Loc has 18 inner classes, 5 inner traits, 7 inner objects. There're tons of codes write like this. I wanna to know why the author write it like this. Is it because it's the author's personal taste or a powerful use of language feature?

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  • Resetting a while loop

    - by Patrick Beardmore
    I have found a confusing thing in a php script I am writing to generate some javascript. Here it is below, slightly simplified. The second while loop won't run unless I comment out the entire first while loop. Can anyone explain why? Many thanks. <?php $listid = 2; //DEMO ONLY $result1 = mysql_query("SELECT words.wid,words.wordmd5,words.word FROM words,instances WHERE words.wid = instances.wid AND instances.lid = \"$listid\""); $result1copy = $result1; $count1 = 1; while( $row = mysql_fetch_object( $result1 ) ) { print "words_left[$count1] = \"".$row->word."\";\n"; //Increment the array counter (starts at 1) $count1++; } ?> //Some javascript <?php $count2 = 1; while( $row = mysql_fetch_object( $result1copy ) ) { print " $count2 then $row->wordmd5 "; $count2++; } ?>

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  • Drawing lines between windows just like in Interface Builder

    - by Koning Baard
    I have two windows, each with a round NSView: ------------------ ------------ |X-+ Oscillator | |X-+ Mixer | |----------------| |----------| | | | | | O | | O | | | | | | | | | ------------------ ------------ Both windows are in a seperate NIB. I want to be able to draw a line between the two round NSViews at runtime, using drag'n'drop, just like connecting IBOutlets in Interface Builder: ------------------ ------------ |X-+ Oscillator | |X-+ Mixer | |----------------| |----------| | | | | | O-------+-----+-----O | | | | | | | | | ------------------ ------------ I also want to be able to determine to which NSViews the NSViews are connected using the drawn lines. I need this to connect Oscillators to Mixers. I also want to be able to remove the connections by dragging into empty space. Can anyone explain me how to do this? Thanks.

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  • [MySQL] Optimize Query

    - by bordeux
    Hello. I have problem with optimize this query: SET @SEARCH = "dokumentalne"; SELECT SQL_NO_CACHE `AA`.`version` AS `Version` , `AA`.`contents` AS `Contents` , `AA`.`idarticle` AS `AdressInSQL` , `AA` .`topic` AS `Topic` , MATCH (`AA`.`topic` , `AA`.`contents`) AGAINST (@SEARCH) AS `Relevance` , `IA`.`url` AS `URL` FROM `xv_article` AS `AA` INNER JOIN `xv_articleindex` AS `IA` ON ( `AA`.`idarticle` = `IA`.`adressinsql` ) INNER JOIN ( SELECT `idarticle` , MAX( `version` ) AS `version` FROM `xv_article` WHERE MATCH (`topic` , `contents`) AGAINST (@SEARCH) GROUP BY `idarticle` ) AS `MG` ON ( `AA`.`idarticle` = `MG`.`idarticle` ) WHERE `IA`.`accepted` = "yes" AND `AA`.`version` = `MG`.`version` ORDER BY `Relevance` DESC LIMIT 0 , 30 Now, this query using ^ 20 seconds. How to optimize this? EXPLAIN gives this: 1 PRIMARY AA ALL NULL NULL NULL NULL 11169 Using temporary; Using filesort 1 PRIMARY ALL NULL NULL NULL NULL 681 Using where 1 PRIMARY IA ALL accepted NULL NULL NULL 11967 Using where 2 DERIVED xv_article fulltext topic topic 0 1 Using where; Using temporary; Using filesort This is example server with my data: user: bordeux_4prog password: 4prog phpmyadmin: http://phpmyadmin.bordeux.net/ chive: http://chive.bordeux.net/

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  • Is this a valid C statement ?

    - by Philando Gullible
    Lets say I write char c[99] = {'Stack Overflow'}; in C or C++ it does compiles fine but does this valid? By valid I meant not invoking any kind of undefined or unspecified behavior. Again if I write char c[99] = 'Stack Overflow'; gcc complains about multicharacter constant which is obvious but in the above when I am enclosing within curly brackets compiler is happy! why is it so ? I also notice that puts(c); after the first statement will output 'w' precisely the last character of a general string in-place of Stack Overflow. why so ? Could somebody explain this behavior may be separately.

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  • What machine learning algorithms can be used in this scenario?

    - by ExceptionHandler
    My data consists of objects as follows. Obj1 - Color - shape - size - price - ranking So I want to be able to predict what combination of color/shape/size/price is a good combination to get high ranking. Or even a combination could work like for eg: in order to get good ranking, the alg predicts best performance for this color and this shape. Something like that. What are the advisable algorithms for such a prediction? Also may be if you can briefly explain how I can approach towards the model building I would really appreciate it. Say for eg: my data looks like Blue pentagon small $50.00 #5 Red Squre large $30.00 #3 So what is a useful prediction model that I should look at? What algorithm should I try to predict like say highest weightage is for price followed by color and then size. What if I wanted to predict in combinations like a Red small shape is less likely to higher rank compared to pink small shape . (In essence trying to combine more than one nominal values column to make the prediction)

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  • Reading a bmp file and inverting it in C

    - by user1763396
    I have an assignment that deals with reading a bmp file into memory, inverts the pixels, and then saves the inverted image to a new file. From this description it seems fairly easy, however I don't think my professor did a great job in explaining the necessary steps to go about doing so. He taught us about fread and fwrite but there is so much more. Can anyone explain the process in going about this problem (I'm no looking for a direct answer just an explanation). Here is the link to the problem's description: https://engineering.purdue.edu/OOSD/F2012/Exercises/ex5.html Thanks in advance for any sort of help. NOTE: I actually have looked into this problem but since I don't have a good standing on this info it's not quite "clicking".

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  • Javascript: Retrieve Object Property Names

    - by Jason
    I'm trying to write a function that needs to know the property names of an object being passed in, like so: var data = { "key1":"value1", "key2":"value2", etc} ^ i want the string value "key1" How do I retrieve the string "key1" from data? I know I can set a property dynamically like data[prop]=value but i want to know what prop is from an object passed in. If that doesn't make sense I suppose I could try to explain more. Thanks! I eventually want to do something like: for (var i = 0; i<data.length; i++) { var name = data[i].getPropertyName() <--- not a real function // do stuff }

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  • About memory and delete object in c++

    - by barssala
    I will give some examples and explain. First, I declare some object like CString* param = new CString[100] And when I declare this one, my memory would increase a little bit because it's some implemented string. Then I store this object in some list of CString just like List<CString> myList = new List<CString>; // new list of CString myList.add(param); This is my question: I wanna know, when I delete myList, my param isn't deleted, right? And memory in param still exists. Do I misunderstand?

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  • Can I use a single pointer for my hash table in C?

    - by aks
    I want to implement a hash table in the following manner: struct list { char *string; struct list *next; }; struct hash_table { int size; /* the size of the table */ struct list **table; /* the table elements */ }; Instead of struct hash_table like above, can I use: struct hash_table { int size; /* the size of the table */ struct list *table; /* the table elements */ }; That is, can I just use a single pointer instead of a double pointer for the hash table elements? If yes, please explain the difference in the way the elements will be stored in the table?

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  • Graphics Question: How do I restrict the mouse cursor to within a circle?

    - by Dan
    I'm playing with XNA. When I click the left mouse button, I record the X,Y co-ordinates. Keeping the mouse button held down, moving the mouse draws a line from this origin to the current mouse position. I've offset this into the middle of the window. Now, what I'd like to do is restrict the mouse cursor to within a circle (with a radius of N, centred on the middle of the screen). Restricting the mouse to a rectangular region is easy enough (by adjusting the origin by the difference of the mouse position and the size of the region), but I haven't a clue on how to start doing it for a circular region. Can anyone explain how to do this? Any advice on where to start would be helpful.

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  • base pointer to derived class

    - by Jay
    Suppose there are Base class and Derived class. Base *A = new Base; Here A is a pointer point to Base class, and new constructs one that A points to. I also saw Base *B = new Derived; How to explain this? B is a pointer to Base Class, and a Derived class constructed and pointed by B? If there is a function derived from Base class, say, Virtual void f(), and it's been overridden in Derived class, then B->f() will invoke which version of the function? version in Base class, or version that overridden in Derived Class. What if there is a new function void g()in Derived, is B->g() going to invoke this function properly? One more is, is int *a = new double; or int *a = new int; legal?

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  • Suspension of Gmail account [closed]

    - by Ifeanyi Agu
    I have a Joomla site with my gmail account (google apps) being used as the SMTP server for sending mails. I also have a newsletter component on this site. I tried sending newsletter to all my subscribers and I noticed that the SMTP server could not be connected to. I then checked the emails of my company and noticed that the one I used to set it up was suspended. I cannot really explain why Google suspended the email account. Please could anyone tell me if Google saw the mails that were being sent as spam.

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  • Threads in JAVA

    - by theband
    I was today asked in an interview over the Thread concepts in JAVA? The Questions were... What is a thread? Why do we go for threading? A real time example over the threads. Can we create threads in Spring framework service class. Can flex call a thread? I did not answer any questions apart from definition of Thread, that too i just learnt from internet. Can anyone explain me clearly over this.

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