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  • Beginner to RUBY - require_relative problem

    - by WANNABE
    Hi, I'm learning Ruby (using version 1.8.6) on Windows 7. When I try to run the stock_stats.rb program below, I get the following error: C:\Users\Will\Desktop\ruby>ruby stock_stats.rb stock_stats.rb:1: undefined method `require_relative' for main:Object (NoMethodE rror) I have three v.small code files: stock_stats.rb require_relative 'csv_reader' reader = CsvReader.new ARGV.each do |csv_file_name| STDERR.puts "Processing #{csv_file_name}" reader.read_in_csv_data(csv_file_name) end puts "Total value = #{reader.total_value_in_stock}" csv_reader.rb require 'csv' require_relative 'book_in_stock' class CsvReader def initialize @books_in_stock = [] end def read_in_csv_data(csv_file_name) CSV.foreach(csv_file_name, headers: true) do |row| @books_in_stock << BookInStock.new(row["ISBN"], row["Amount"]) end end # later we'll see how to use inject to sum a collection def total_value_in_stock sum = 0.0 @books_in_stock.each {|book| sum += book.price} sum end def number_of_each_isbn # ... end end book_in_stock.rb require 'csv' require_relative 'book_in_stock' class CsvReader def initialize @books_in_stock = [] end def read_in_csv_data(csv_file_name) CSV.foreach(csv_file_name, headers: true) do |row| @books_in_stock << BookInStock.new(row["ISBN"], row["Amount"]) end end # later we'll see how to use inject to sum a collection def total_value_in_stock sum = 0.0 @books_in_stock.each {|book| sum += book.price} sum end def number_of_each_isbn # ... end end Thanks in advance for any help.

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  • Dynamic attributes with Rails and Mongoid

    - by japancheese
    Hello, I'm learning MongoDB through the Mongoid Ruby gem with Rails (Rails 3 beta 3), and I'm trying to come up with a way to create dynamic attributes on a model based on fields from another model, which I thought a schema-less database would be a good choice for. So for example, I'd have the models: class Account include Mongoid::Document field :name, :type => String field :token, :type => String field :info_needed, :type => Array embeds_many :members end class Member include Mongoid::Document embedded_in :account, :inverse_of => :members end I'm looking to take the "info_needed" attribute of the Account model and created dynamic attributes on the Member model based on what's inside. If club.info_needed was ["first_name", "last_name"], I'm trying to create a form that would save first_name and last_name attributes to the Member model. However, upon practice, I just keep getting "undefined method first_name=" errors on the Member model when trying to do this. I know MongoDB can handle dynamic attributes per record, but how can I get Mongoid to do this without an undefined method error?

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  • Sending persisted JDO instances over GWT-RPC

    - by Ben Daniel
    I've just started learning Google Web Toolkit and finished writing the Stock Watcher tutorial app. Is my thinking correct that if one wants to persist a business object (like a Stock) using JDO and send it back and forth to/from the client over RPC then one has to create two separate classes for that object: One with the JDO annotations for persisting it on the server and another which is serialisable and used over RPC? I notice the Stock Watcher has separate classes and I can theorise why: Otherwise the gwt compiler would try to generate javascript for everything the persisted class referenced like JDO and com.google.blah.users.User, etc Also there may be logic on the server-side class which doesn't apply to the client and vice-versa. I just want to make sure I'm understanding this correctly. I don't want to have to create two versions of all my business object classes which I want to use over RPC if I don't have to.

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  • how u guys learn coding and programming

    - by dramasea
    Hi, I am a newbie on programming and currently still learning. Can you contribute your opinion on how to learn that faster. I learn every single element of the language such as Javascript date object methods and properties: http://www.w3schools.com/jsref/jsref_obj_date.asp but it is pretty much all the same, should i read through it? or i just left it. You know that's very boring with just reading. So, can I ask those professional programmer, do you also read these when you learn programming?

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  • I keep getting a "System InvalidOperationException occurred in System Windows Forms dll" error in VB

    - by Heartrent
    I've just started learning VB.NET with VS 9.0; a small application I'm working on keeps returning an "A first chance exception of type System InvalidOperationException occurred in System Windows Forms dll" error from the Immediate Window. The application has almost zero functionality so far, it consists of a menu strip with: File About |Open |Save |Save As |Quit The only code I have written opens an Open File dialog, a Save As dialog, an About window with background sound and an OK button, and the Quit button which exits. Since there is almost no code for me to search through, I can't understand why there would be an error. The program runs just fine when I'm debugging it too.

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  • Help converting java program to MapReduce job

    - by BigJoe714
    Hello, I would like to convert the following Java program to a MapReduce job. I have read about MapReduce and feel like this would be a good problem to solve using it, but I cannot figure out what to do. This basically loops through a directory of html files and parses them into a CSV file. http://www.joeharrison.com/bucket/2010/3/Main.java.txt http://www.joeharrison.com/bucket/2010/3/StringParser.java.txt Note: I am not trying to get someone else to do my work for me. I am using this as a learning experience. This will not be used for $$$profit$$$. If I have something that I created converted to a MapReduce job I feel it will provide a much easier way to learn then trying to follow an arbitrary tutorial. I posted this on Rentacoder several days ago, because I wanted to pay someone to convert it for me. But no one on rentacoder seems to know mapreudce!

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  • A report writer for non-programmers?

    - by Earlz
    Hello, we are wanting for users to be able to write their own reports in our application. It is a web application. We don't care if they must download an application in order to create reports, but we need for them to be able to print off reports from the web in PDF format or similar. The report writer is to be used by non-programmers, or at best very light programmers(like the ones that make VBA macros and such). (the writer is not a core part of the program though. So if there is a learning curve, then that is acceptable to a certain extent) We were looking at Crystal Reports but it seems like it'll cost $7000 which is just way too much for right now(though our system is very flexible so could support it eventually). We are also looking at Fast Reports which seems pretty promising, but I'm not sure the report writer would be easy for non-programmers to grasp. Can someone recommend a good report writer for non programmers that won't break the bank?

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  • How to get the data for intra-day candlestick charts for stocks on eg Nasdaq

    - by Chris
    Hi, For a learning exercise, i'm wanting to create candlestick (stock) graphs for stocks using zedgraph. Now on google finance, i can get daily open-high-low-close data which is perfect for making these graphs, but i'm wanting to create intra-day graphs, eg open-high-low-close data for an hour (or 5 mins, or 1 min even). Is there any way to get that kind of data without having to subscribe to any expensive service? I've heard opentick mentioned in an old SO question, but their site is defunct now. I was thinking of polling google finance once a minute to get the latest stock price, then with an hour's worth of 60 prices, i could then roughly calculate the open-high-low-close, but this is a bit of an estimation and i'm open to other suggestions. Cheers all.

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  • Desktop development vs Web development

    - by Sahat
    After doing some google search I've came to conclusion that desktop development is shifting to the web development. Recent demos of HTML5 show us 3D accelerated games running inside of a browser. Is it true that desktop development is slowly dying? Would it make more sense learning ASP.NET, Silverlight and HTML5 rather than the desktop side of .NET such as WinForms and WPF. Who is leading current job trends: Software development or Web development? Who will lead in the near future?

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  • Errno::EACCES: Permission denied - ./tmp/rspec_guard_result

    - by Evgeniy Gatsalov
    Trying settup rspec-guard-spork for learning app from http://ruby.railstutorial.org/ Using Ruby 2.0, Rails 4.0 on Windows7 ( I know :( ) When starting guard, get: 23:02:51 - ERROR - Guard::RSpec failed to achieve its <run_on_modifications>, exception was: > [#] Errno::EACCES: Permission denied - ./tmp/rspec_guard_result ... All gemfile, guardfile etc are edited according tutorial. Except 1) deleting win32console gem from gemfile because it turned console-out into a crap and raised an error. Permissions for a file is "F"(ull) for all cattegories: D:\WebDevelop\sample_appcacls tmp\rspec_guard_result D:\WebDevelop\sample_app\tmp\rspec_guard_result BUILTIN\Users:(ID)F NT AUTHORITY\Authenticated:(ID)F BUILTIN\Administrators:(ID)F NT AUTHORITY\system:(ID)F What additional info should I provide here?

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  • Where can I download a free, text-rich dataset?

    - by blee
    I want to do a bit of lightweight testing and bench-marking for full-text search, so the dataset should have the qualities: 10,000 - 100,000 records. good dispersion of English words. In CSV or Excel format--i.e. I don't want to access it via API. Something like books or movies with title and description fields would be perfect. I browsed the UCI Machine Learning Repo, but it was too number-oriented. Thanks!

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  • Lua pattern matching vs. regular expressions

    - by harald
    hello, i'm currently learning lua. regarding pattern-matching in lua i found the following sentence in the lua documentation on lua.org: Nevertheless, pattern matching in Lua is a powerful tool and includes some features that are difficult to match with standard POSIX implementations. as i'm familiar with posix regular expressions i would like to know if there are any common samples where lua pattern matching is "better" compared to regular expression -- or did i misinterpret the sentence? and if there are any common examples: why is any of pattern-matching vs. regular expressions better suited? thanks very much, harald

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  • naive bayesian spam filter question

    - by Microkernel
    Hi guys, I am planning to implement spam filter using Naive Bayesian classification model. Online I see a lot of info on Naive Bayesian classification, but the problem is its a lot of mathematical stuff, than clearly stating how its done. And the problem is I am more of a programmer than a mathematician (yes I had learnt Probability and Bayesian theorem back in school, but out of touch for a long long time, and I don't have luxury of learning it now (Have nearly 3 weeks to come-up with a working prototype)). So if someone can explain or point me to location where its explained for programmers than a mathematician, it would be a great help. PS: By the way I have to implement it in C, if you want to know. :( Regards, Microkernel

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  • Writing an Iron Python debugger

    - by Kragen
    As a learning exercise I'm writing myself a simple extension / plugin / macro framework using IronPython - I've gotten the basics working but I'd like to add some basic debugging support to make my script editor easier to work with. I've been hunting around on the internet a bit and I've found a couple of good resources on writing managed debuggers (including Mike Stall's excellent .Net Debugging blog and the MSDN documentaiton on the CLR Debugging API) - I understand that IronPython is essentially IL however apart from that I'm a tad lost on how to get started, in particular: Are there any significant differences between debugging a dynamic language (such as IronPython) to a static one (such as C#)? Do I need to execute my script in a special way to get IronPython to output suitable debugging information? Is debugging a script running inside the current process going to cause deadlocks, or does IronPython execute my script in a child process? Am I better off looking into how to produce a simple C# debugger first to get the general idea? (I'm not interested in the GUI aspect of making a debugger for now - I've already got a pretty good idea of how this might work)

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  • MVVM Good Design. DataSet or a RowViewModel

    - by LnDCobra
    I have just started learning MVVM and having a dilemna. If I have a a main ViewModel and inside this model I have a number of datasets. Now should I be creating a new ViewModel for each row inside the dataset? Or expose the DataSet itself as a DependencyProperty? For now the dataset has about 20 rows inside it, and the thought of iterating through each row to create a ViewModel binding to each row.... might not be the best option for performance reasons and memory reasons in the future, like when there are 1000+ rows. Should I still go ahead and create a RowViewModel and iterate through the dataset? And have an ObservableCollection of it or just expose the dataset? Any help would be greatly appreciated.

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  • async handler deleted by the wrong thread in django

    - by user3480706
    I'm run this algorithm in my django application.when i run several time from my GUI django local server will stopped and i got this error Exception RuntimeError: RuntimeError('main thread is not in main loop',) in ignored Tcl_AsyncDelete: async handler deleted by the wrong thread Aborted (core dumped) code print "Learning the sin function" network =MLP.MLP(2,10,1) samples = np.zeros(2000, dtype=[('x', float, 1), ('y', float, 1)]) samples['x'] = np.linspace(-5,5,2000) samples['y'] = np.sin(samples['x']) #samples['y'] = np.linspace(-4,4,2500) for i in range(100000): n = np.random.randint(samples.size) network.propagate_forward(samples['x'][n]) network.propagate_backward(samples['y'][n]) plt.figure(figsize=(10,5)) # Draw real function x = samples['x'] y = samples['y'] #x=np.linspace(-6.0,7.0,50) plt.plot(x,y,color='b',lw=1) samples1 = np.zeros(2000, dtype=[('x1', float, 1), ('y1', float, 1)]) samples1['x1'] = np.linspace(-4,4,2000) samples1['y1'] = np.sin(samples1['x1']) # Draw network approximated function for i in range(samples1.size): samples1['y1'][i] = network.propagate_forward(samples1['x1'][i]) plt.plot(samples1['x1'],samples1['y1'],color='r',lw=3) plt.axis([-2,2,-2,2]) plt.show() plt.close() return HttpResponseRedirect('/charts/charts') how can i fix this error ?need a quick help

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  • what languages are used in AI research today?

    - by aaa
    hi. I am currently dabbling in expert systems, emacs lisp, and reading up about artificial intelligence. Traditionally, artificial intelligence is associated with LISP and expert systems with CLIPS. However, I have noticed in computational sciences how much Python is being used. What about the area of artificial intelligence and machine learning? is it still been dominated by LISP? how much is python being used in AI? are any of the newer functional languages, clojure for example, being used in research? in the area of expert systems, which shells are most used/popular today? are there any interesting developments language wise which you know of? Thanks a lot

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  • Just quick: How do you call a mutator from within a constructor in the same class?

    - by Blockhead
    For a homework assignment the instructions state (within Undergrad class): You do NOT need to include a default constructor, but you must write a full parameterized constructor (it takes 4 arguments) -- this constructor calls the parent class parameterized constructor and the mutator for year level. Because Undergrad extends Student, then Student is my parent class, right? I just can't quite figure out how I'm to use my year level mutator (which is just the simplest of methods) to assign my "year" attribute. public void setYear(int inYear) { year = inYear; } public Student(String inName, String inID, int inCredits) { name = inName; id = inID; credits = inCredits; } public Undergrad(String inName, String inID, int inCredits,int inYear) { super(inName, inID, inCredits); year = inYear; } I keep missing assignments because I spend too much time on these small specific points of the homework so just asking for a little help. I swear it's the wording that throws me off on these assignments almost as often as just learning the material itself.

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  • Python repl in python application

    - by Olorin
    Hello i am learning python(so i can use qt with python not only c++) and i'm curios if it would be possible to embed a python interpreter in my application as a repl. I would like to give users to possibility to script the app using python either loading a file (and that file to act as a plugin for the app) or by evaluating code entered in a text box or something like that. Just like you can embed the interpreter in C or C++ and script the app using python can this be done if the application is itself written in python(and made a stand-alone binary using py2exe or something similar)? something like Anders did with the C# repl or Miguel with mono. Thanks.

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  • Protected Members of Other Instances in Scala

    - by Masterofpsi
    I just ran into a difficulty while learning Scala. I have an inheritance hierarchy that is essentially equivalent to this: class A { protected def myMethod() = println("myMethod() from A") } class B extends A { def invokeMyMethod(a: A) = a.myMethod() } But trying to compile this sample, I get the error "test.scala:7: error: method myMethod cannot be accessed in A". Coming from Java, my understanding is that protected members should be accessible at any point from a derived class, and nowhere have I seen anything that tells me that protected members in Scala are limited by instance. Does anyone have an explanation for this?

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  • How to use the md5 hash?

    - by Ken
    Okay, so I'm learning php, html, and mysql to learn website development (for fun). One thing I still don't get is how to use md5 of sha1 hashes. I know how to hash the plain text, but say I want to make a login page. Since the password is hashed and can't be reversed, how would mysql know that the user-inserted password matches the hashed password in the database? Here is what I mean: $password = md5($_POST['password']); $query = ("INSERT INTO `users`.`data` (`password`) VALUES ('$password')"); I know that this snippet of script hashes the password, but how would I use this piece of code and make a login page? Any working examples would be great.

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  • Rails ActionMailer problems on Mac

    - by seth
    I've been working on learning to use Rails the last couple days and I've run into something that I haven't been able to solve with Google. So I'm just creating a basic contact form that sends an email. Everything seems to be working ok in testing, which tells me that the form is working, and ActionMailer was implemented correctly, however, I'm having trouble configuring ActionMailer. I'm running OSX 10.6.2. I have postfix running and have verified that it's running using telnet localhost 25. When I try to use the form I get a "Connection refused" error. This is my current configuration: config.action_mailer.smtp_settings = { :address => 'localhost', :port => 25 } I thought I might need to set :domain but I'm kind of confused on what that should be set to in this situation.

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  • URL on apache server does not default to the .php file after / has been added

    - by jeffkee
    Generally a url that looks like this: http://www.domain.com/product.php/12/ will open up product.php and serve the /12/ as request parameters, which then my PHP script can process to pull out the right product info. However when I migrated this whole site, after developing it, to a new server, I get a 404 error, because on that server it's not defaulting to the mother directory/file in case of an absence of requested directories. I vaguely remember learning that this is generally a common apache function but I can't seem to recall how to set it up or how to manipulate it.. if there's an .htaccess method to achieve this that would be great.

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  • Creating a form for editing embedded documents with MongoMapper

    - by Luke Francl
    I'm playing around with MongoMapper but I'm having trouble figuring out how to create a form for an object that has embedded documents. With ActiveRecord, I'd use fields_for but when asked if this would be supported a few months ago, MongoMapper author John Nunemaker wrote: "Nope and nope. It is really [not] that hard with attr_accessor's." OK, fair enough, but how do you write the form for this to work? I'm not interested in using the nested form implementations that are out there because I want to do this the "normal" way as I'm learning about MongoMapper. My model is simple enough - I've got a Person with embedded documents for email addresses, phone numbers, etc. I do not care about updating existing embedded documents. They can be re-created from the form input each time a Person is edited.

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  • How to display image in grails GSP?

    - by Walter
    I'm still learning Grails and seem to have hit a stumbling block. Here are the 2 domain classes: class Photo { byte[] file static belongsTo = Profile } class Profile { String fullName Set photos static hasMany = [photos:Photo] } The relevant controller snippet: class PhotoController { ..... def viewImage = { def photo = Photo.get( params.id ) byte[] image = photo.file response.outputStream << image } ...... } Finally the GSP snippet: <img class="Photo" src="${createLink(controller:'photo', action:'viewImage', id:'profileInstance.photos.get(1).id')}" /> Now how do I access the photo so that it will be shown on the GSP? I'm pretty sure that profileInstance.photos.get(1).id is not correct. Thanks!!

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