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  • Calculating statistics directly from a CSV file

    - by User1
    I have a transaction log file in CSV format that I want use to run statistics. The log has the following fields: date: Time/date stamp salesperson: The username of the person who closed the sale promo: sum total of items in the sale that were promotions. amount: grand total of the sale I'd like to get the following statistics: salesperson: The username of the salesperson being analyzed. minAmount: The smallest grand total of this salesperson's transaction. avgAmount: The mean grand total.. maxAmount: The largest grand total.. minPromo: The smallest promo amount by the salesperson. avgPromo: The mean promo amount... I'm tempted to build a database structure, import this file, write SQL, and pull out the stats. I don't need anything more from this data than these stats. Is there an easier way? I'm hoping some bash script could make this easy.

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  • How do i change Object to String in a class which extends AsyncTask?

    - by Filip V.
    I'm learning from Google's Android developing tutorial and i came across a problem. On this link https://developer.android.com/training/basics/network-ops/connecting.html#AsyncTask it says to create a class that extends AsyncTask. So when i write the class it automatically implements the method as follows: private Object doInBackground(Object... args) {..} //it's fine but when i try writing just as it says in the tutorial: private String doInBackground(String... args) {..} //it gives an error and the error says: The method doInBackground(String...) of type MainActivity.DownloadWebpageText must override a superclass method. So how do i change Object to String without getting an error there?

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  • What's a good place to unregister an observer from the notification center?

    - by mystify
    When I add an observer to the default notification center, where would I unregister that? Example: I have a UIView subclass which lives inside a view controller. That subclass is an observer for the FooBarNotification. If this notification is posted, that view will get it. But now, the view controller decides to throw away the view. Is the best place the -dealloc method of the view itself? Are there any rules like memory management rules? For example: Must I unregister an observer where I registered it? i.e. the view registers itself in it's init method, so it should unregister itself in it's -dealloc method? (not talking about push notifications, but NSNotificationCenter)

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  • how to get a constant in java with class

    - by vincent
    basically I need to get a constant for a class however I have no instance of the object but only its class. In PHP I would do constant(XYZ); Is there a similar way of retrieving a constant in JAVA? I need it to facilitate a dynamic getMethod call Class parameterType = Class.forName(class_name); object.setProperty(field name, field value, parameterType); the set property method would then get the correct method and set the specified property, however I cant get a method which has int as parameter type without using Interger.TYPE

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  • Device drivers and Windows

    - by b-gen-jack-o-neill
    Hi, I am trying to complete the picture of how the PC and the OS interacts together. And I am at point, where I am little out of guess when it comes to device drivers. Please, don´t write things like its too complicated, or you don´t need to know when using high programming laguage and winapi functions. I want to know, it´s for study purposes. So, the very basic structure of how OS and PC (by PC I mean of course HW) is how I see it is that all other than direct CPU commands, which can CPU do on itself (arithmetic operation, its registers access and memory access) must pass thru OS. Mainly becouse from ring level 3 you cannot use in and out intructions which are used for acesing other HW. I know that there is MMIO,but it must be set by port comunication first. It was not like this all the time. Even I am bit young to remember MSDOS, I know you could access HW directly, becouse there ws no limitation, no ring mode. So you could to write string to diplay use wheather DOS function, or directly acess video card memory and write it by yourself. But as OS developed, there is no longer this possibility. But it is fine, since OS now handles all the HW comunication, and frankly it more convinient and much more safe (I would say the only option) in multitasking environment. So nowdays you instead of using int instructions to use BIOS mapped function or DOS function you call dll which internally than handles everything you don´t need to know about. I understand this. I also undrstand that device drivers is the piece of code that runs in ring level 0, so it can do all the HW interactions. But what I don´t understand is connection between OS and device driver. Let´s take a example - I want to make a sound card make a sound. So I call windows API to acess sound card, but what happens than? Does windows call device drivers to do so? But if it does call device driver, does it mean, that all device drivers which can be called by winAPI function, must have routines named in some specific way? I mean, when I have new sound card, must its drivers have functions named same as the old one? So Windows can actually call the same function from its perspective? But if Windows have predefined sets of functions requored by device drivers, that it cannot use new drivers that doesent existed before last version of OS came out. Please, help me understand this mess. I am really getting mad. Thanks.

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  • Error 400 in urllib2 when using cookies

    - by Hempage
    I've had some success using a different method to load cookies, but now I'm wanting to use the cookielib.MozillaCookieJar method to open a cookies.txt file. Here's the snippet of code that does this. cookieJar=MozillaCookieJar() cookieJar.load(argv[2]) After creating an HTTPCookieProcessor opener, and installing it, whenever I use urlopen, I get an HTTP 400 error. However, if I don't use a CookieJar, the urlopen method succeeds (though the response doesn't contain the data I need). I'm not sure whether the cookies.txt file is malformed, or whether there's something else going on.

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  • Finding good heuristic for A* search

    - by Martin
    I'm trying to find the optimal solution for a little puzzle game called Twiddle (an applet with the game can be found here). The game has a 3x3 matrix with the number from 1 to 9. The goal is to bring the numbers in the correct order using the minimum amount of moves. In each move you can rotate a 2x2 square either clockwise or counterclockwise. I.e. if you have this state 6 3 9 8 7 5 1 2 4 and you rotate the upper left 2x2 square clockwise you get 8 6 9 7 3 5 1 2 4 I'm using a A* search to find the optimal solution. My f() is simply the number of rotations need. My heuristic function already leads to the optimal solution but I don't think it's the best one you can find. My current heuristic takes each corner, looks at the number at the corner and calculates the manhatten distance to the position this number will have in the solved state (which gives me the number of rotation needed to bring the number to this postion) and sums all these values. I.e. You take the above example: 6 3 9 8 7 5 1 2 4 and this end state 1 2 3 4 5 6 7 8 9 then the heuristic does the following 6 is currently at index 0 and should by at index 5: 3 rotations needed 9 is currently at index 2 and should by at index 8: 2 rotations needed 1 is currently at index 6 and should by at index 0: 2 rotations needed 4 is currently at index 8 and should by at index 3: 3 rotations needed h = 3 + 2 + 2 + 3 = 10 But there is the problem, that you rotate 4 elements at once. So there a rare cases where you can do two (ore more) of theses estimated rotations in one move. This means theses heuristic overestimates the distance to the solution. My current workaround is, to simply excluded one of the corners from the calculation which solves this problem at least for my test-cases. I've done no research if really solves the problem or if this heuristic still overestimates in same edge-cases. So my question is: What is the best heuristic you can come up with? (Disclaimer: This is for a university project, so this is a bit of homework. But I'm free to use any resource if can come up with, so it's okay to ask you guys. Also I will credit Stackoverflow for helping me ;) )

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  • How might you unobtrusively enhance the jQuery Datepicker class?

    - by Teflon Ted
    You can pass special strings into jQuery's Datepicker class setDate() method like "+7" which will be translated into "7 days from today": http://docs.jquery.com/UI/Datepicker#method-setDate But you can't get that "+7" back out. When you call getDate() you get the calculated resulting date. I have a use case where I need to pull out the special string "+7" for propagation. One chunk of code is passing a special string into the Datepicker and passing the Datepicker over to another chunk of code which pulls out the date, but the latter sometimes needs to know the special string rather than the calculated date. So I need to enhance the Datepicker tool to (a) store the special code internally and (b) expose it via a method like getOriginallyPassedInDate() or some such. I'm not a jQuery/Javascript ninja so I could really use some guidance on how I might preferably-unobtrusively add the necessary functionality to the Datepicker class, the way you might monkey-patch an object in Ruby I'm guessing.

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  • Java vs C# - AddActionListener vs event subscription

    - by S.O.
    Very simple question from one somewhat new to Java: when adding an event handler (or whatever it is called in Java) to a Control, MUST it be an object? I mean, in C# I can do control.event += System.eventHandler(methodThatHandlesEvent) Sure, that's because we have delegate types in C#, but I was wondering if I can choose which method would be called when an event is raised in Java? I mean, in Java I can have something like control.AddActionListener(objectWhichClassImplementsActionListener) And then I have the stupid actionPerformed method in this class, which is the only method that is called. I know, there are more kinds of listeners, but I can't have a "ActionListenerHandler" class in which I implement several actionPerformed methods that can be assigned to different controls?

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  • What's the best way to return a subset of a list

    - by Pikrass
    I have a list of tasks. A task is defined by a name, a due date and a duration. My TaskManager class handles a std::list<Task> sorted by due date. It has to provide a way to get the tasks due for a specific date. How would you implement that ? I think a good way (from API point of view) would be to provide a std::list<Task>::iterator pair. So I would have a TaskManager::begin(date) method. Do you think this method should get the iterator by iterating from the start of the list until it finds the first task due on that date, or by getting it from a std::map<date, std::list<Task>::iterator> (but then we have to keep it up-to-date when adding or removing tasks) ? And then, how could I implement the TaskManager::end(date) method ?

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  • OOP question about functions that struck me all of a sudden.

    - by Nitesh Panchal
    Hello, May be my question is stupid. But i would like to get it cleared. We know that functions are loaded in memory only once and when you create new objects, only instance variables gets created, functions are never created. My question is, say suppose there is server and all clients access a method named createCustomer(). Say suppose all clients do something which fired createCustomer on server. So, if the method is in middle of execution and new client fires it. Will the new request be put on wait? or new request also will start executing the method? How does it all get managed when there is only one copy of function in memory? No book mentions answers to this type of questions. So i am posting here where i am bound to get answers :).

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  • When to use try/catch

    - by coffeeaddict
    I'm always finding myself wanting to put a try/catch around the lets say Business Layer methods. But I feel though that I don't need a try/catch if I'm simply rethrowing it up to the Presentation Layer. Is that right? I should not be rethrowing an exception from code that's wrapped in a try/catch in a BL method and should be letting the caller which would be from the Presentation Layer code be using a try/catch to handle it there? The BL method will throw an error without the try/catch anyway..the compiler will. So it wouldn't make sense to use a try/catch in a BL method that's to be consumed by a layer higher up correct?

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  • How to learn about Make, compiling

    - by drozzy
    Why is Make utility for installing stuff on Linux so complicated? I mean it is really hard to know exactly where stuff goes on the machine. /etc/local? usr local? non-local? It just seems like really chaotic directory structure. Is there some "guide" on how this works? I mean as a new programmer, coming into the world of compiling things - where does on start? Thanks.

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  • form doesn't work after use render

    - by Rodrigo
    I trying to use render method inside my activeAdmin form method, but after insert render in code, it stopped to work. form do |f| f.inputs I18n.t('sale_header') do f.input :client f.input :room end f.inputs I18n.t('sale_items') do render :partial => "form_sale" end f.inputs I18n.t('totalization') do f.input :sub_total, :input_html => { :disabled => :true } f.input :discount f.input :total_value, :input_html => { :disabled => :true } end f.buttons end After insert the render method, only form_sale content is showed on screen. Any help? Thank You!

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  • Commenting system for CakePHP blog tutorial

    - by Ryan
    I'm building off the CakePHP tutorial for the blog engine by adding comments to each post. I am able to add comments by selecting the post that it should be attached to, via a select box. I would like to be able to click an "Add Comment" link within the post and have the association to the post formed programatically. I am unsure how I can pass the post_id to the add method within my comments_controller. The body of my add method is the auto-generated scaffold code. Is it as easy as adding a $postId argument to the add method and write this to the post_id in my comments model? This doesn't feel right though, since I would expect add to be called when my submit button is click on my comments add view. Thanks all.

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  • What's safe to assume about the NSMutableArray / NSArray class cluster?

    - by andyvn22
    I know you shouldn't use this to decide whether or not to change an array: if ([possiblyMutable isKindOfClass:[NSMutableArray class]]) But say I'm writing a method and need to return either an NSMutableArray or an NSArray, depending on the mutability of possiblyMutable. The class using my method already knows whether or not it's acceptable to change the returned array. Whether or not it's acceptable to change the returned array directly correlates with whether or not it's acceptable to change possiblyMutable. In that specific case, is this code safe? It seems to me that if it's not acceptable to change the array, but we accidentally get a mutable array, it's ok, because the class using my method won't try to change it. And if it is acceptable to change the array, then we will always get possiblyMutable as an NSMutableArray (though this is the part I'm not entirely clear on). So... safe or not? Alternatives?

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  • Help with simple frame, and graphics in Java

    - by Crystal
    For hw, I'm trying to create a "CustomButton" that has a frame and in that frame, I draw two triangles, and a square over it. It's supposed to give the user the effect of a button press once it is depressed. So for starters, I am trying to set up the beginning graphics, drawing two triangles, and a square. The problem I have is although I set my frame to 200, 200, and the triangles I have drawn I think to the correct ends of my frame size, when I run the program, I have to extend my window to make the whole artwork, my "CustomButton," viewable. Is that normal? Thanks. Code: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class CustomButton { public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { CustomButtonFrame frame = new CustomButtonFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } }); } } class CustomButtonFrame extends JFrame { // constructor for CustomButtonFrame public CustomButtonFrame() { setTitle("Custom Button"); setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); CustomButtonSetup buttonSetup = new CustomButtonSetup(); this.add(buttonSetup); } private static final int DEFAULT_WIDTH = 200; private static final int DEFAULT_HEIGHT = 200; } class CustomButtonSetup extends JComponent { public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g; // first triangle coords int x[] = new int[TRIANGLE_SIDES]; int y[] = new int[TRIANGLE_SIDES]; x[0] = 0; y[0] = 0; x[1] = 200; y[1] = 0; x[2] = 0; y[2] = 200; Polygon firstTriangle = new Polygon(x, y, TRIANGLE_SIDES); // second triangle coords x[0] = 0; y[0] = 200; x[1] = 200; y[1] = 200; x[2] = 200; y[2] = 0; Polygon secondTriangle = new Polygon(x, y, TRIANGLE_SIDES); g2.drawPolygon(firstTriangle); g2.setColor(Color.WHITE); g2.fillPolygon(firstTriangle); g2.drawPolygon(secondTriangle); g2.setColor(Color.GRAY); g2.fillPolygon(secondTriangle); // draw rectangle 10 pixels off border g2.drawRect(10, 10, 180, 180); } public static final int TRIANGLE_SIDES = 3; }

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  • Ignoring "Content is not allowed in trailing section" SAXException

    - by Paul J. Lucas
    I'm using Java's DocumentBuilder.parse(InputStream) to parse an XML document. Occasionally, I get malformed XML documents in that there is extra junk after the final > that causes a SAXException: Content is not allowed in trailing section. (In the cases I've seen, the junk is simply one or more null bytes.) I don't care what's after the final >. Is there an easy way to parse an entire XML document in Java and have it ignore any trailing junk? Note that by "ignore" I don't simply mean to catch and ignore the exception: I mean to ignore the trailing junk, throw no exception, and to return the Document object since the XML up to an including the final > is valid.

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  • Export Flash as Transparent MOV

    - by Chris Nicol
    Is it possible to export a flash movie with a transparent background as a .MOV. I don't mean for embedding in a website, I mean the actual .MOV (or .avi). What I'm trying to accomplish is that I have a flash animation that I want to embed in a WPF application. I don't want to use a Browser within the WPF because of all of the issues that surround the browser control (has to be topmost control, etc). So my solution was to export said animation as a movie and play it in the MediaElement control. The only problem is that I need the background to be transparent, and I can't find a way to do this. Any suggestions or alternative solutions would be most welcome.

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  • using jQuery .live with .bind

    - by Aninemity
    okay, I understand the basics of jQuery, and I know that in some instances I've had to use .live('click',function(){...}); instead of .click(function(){...}); to get the method to fire correctly. the method I'm currently looking at is: $('#title').bind('keyup', function(){...}); This works great, except because it's in a bit of code that isn't called until another action is preformed, I'd need to use .live() as described above. Problem is, I don't know how to format this one to work using the .live() method instead of .bind() as shown above. Can someone please help? Thanks in advance!

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