Search Results

Search found 12783 results on 512 pages for 'ruby beginner'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 34/512 | < Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >

  • Explicit return form a Ruby method - implementation hiding, reuse and optimisations.

    - by Chris McCauley
    Hi, Rather than allowing a Ruby method to blindly return the last statement evaluated, is there any advantage to returning nil explicitly? In terms of implementation hiding and reuse, it seems dangerous to blindly allow the last expression evaluated to be returned - isn't there a danger that a user will rely on this only to get a nasty surprise when the implementation is modified? Surely returning nil would be better unless an explicit return value was given. Following on, is there an optimisation that Ruby can make when the return is a simple type rather than a reference to a more complex object? Chris

    Read the article

  • How can I install Ruby on Rails 3 on OSX?

    - by Oluf Nielsen
    Hey i got an White Macbook and, has to go in 10 hours to a conference. And I'm having a lot of problems. First, I wanted to have Rails 3, so I used MacPorts to install Ruby 1.8.7. Tt worked well ;) So now I was thinking I should install Rails 3.. but no, no!.. it says.. $ sudo gem install rails --pre ERROR:   Error installing rails:                  activesupport requires Ruby version = 1.8.7. So what can I do? I have 1.8.7 !

    Read the article

  • Does ActiveRecord make Ruby on Rails code hard to test?

    - by Erik Öjebo
    I've spent most of my time in statically typed languages (primarily C#). I have some bad experiences with the Active Record pattern and unit testing, because of the static methods and the mix of entities and data access code. Since the Ruby community probably is the most test driven of the communities out there, and the Rails ActiveRecord seems popular, there must be some way of combining TDD and ActiveRecord based code in Ruby on Rails. I would guess that the problem goes away in dynamic languages, somehow, but I don't see how. So, what's the trick?

    Read the article

  • Beginner - C# iteration through directory to produce a file list

    - by dassouki
    The end goal is to have some form of a data structure that stores a hierarchal structure of a directory to be stored in a txt file. I'm using the following code and so far, and I'm struggling with combining dirs, subdirs, and files. /// <summary> /// code based on http://msdn.microsoft.com/en-us/library/bb513869.aspx /// </summary> /// <param name="strFolder"></param> public static void TraverseTree ( string strFolder ) { // Data structure to hold names of subfolders to be // examined for files. Stack<string> dirs = new Stack<string>( 20 ); if ( !System.IO.Directory.Exists( strFolder ) ) { throw new ArgumentException(); } dirs.Push( strFolder ); while ( dirs.Count > 0 ) { string currentDir = dirs.Pop(); string[] subDirs; try { subDirs = System.IO.Directory.GetDirectories( currentDir ); } catch ( UnauthorizedAccessException e ) { MessageBox.Show( "Error: " + e.Message ); continue; } catch ( System.IO.DirectoryNotFoundException e ) { MessageBox.Show( "Error: " + e.Message ); continue; } string[] files = null; try { files = System.IO.Directory.GetFiles( currentDir ); } catch ( UnauthorizedAccessException e ) { MessageBox.Show( "Error: " + e.Message ); continue; } catch ( System.IO.DirectoryNotFoundException e ) { MessageBox.Show( "Error: " + e.Message ); continue; } // Perform the required action on each file here. // Modify this block to perform your required task. /* foreach ( string file in files ) { try { // Perform whatever action is required in your scenario. System.IO.FileInfo fi = new System.IO.FileInfo( file ); Console.WriteLine( "{0}: {1}, {2}", fi.Name, fi.Length, fi.CreationTime ); } catch ( System.IO.FileNotFoundException e ) { // If file was deleted by a separate application // or thread since the call to TraverseTree() // then just continue. MessageBox.Show( "Error: " + e.Message ); continue; } } */ // Push the subdirectories onto the stack for traversal. // This could also be done before handing the files. foreach ( string str in subDirs ) dirs.Push( str ); foreach ( string str in files ) MessageBox.Show( str ); }

    Read the article

  • c# beginner problem

    - by Yehonatan
    I am trying to learning C# and I have problem with following code using System; class IfSelect { public static void Main() { string myInput; int myInt; Console.Write("Please enter a number: "); myInput = Console.ReadLine(); myInt = Int32.Parse(myInput); if (myInt = 10) { Console.WriteLine("Your number is 10.", myInt); } } }

    Read the article

  • Beginner SQL question: querying gold and silver tag badges in Stack Exchange Data Explorer

    - by polygenelubricants
    I'm using the Stack Exchange Data Explorer to learn SQL, but I think the fundamentals of the question is applicable to other databases. I'm trying to query the Badges table, which according to Stexdex (that's what I'm going to call it from now on) has the following schema: Badges Id UserId Name Date This works well for badges like [Epic] and [Legendary] which have unique names, but the silver and gold tag-specific badges seems to be mixed in together by having the same exact name. Here's an example query I wrote for [mysql] tag: SELECT UserId as [User Link], Date FROM Badges Where Name = 'mysql' Order By Date ASC The (slightly annotated) output is: as seen on stexdex: User Link Date --------------- ------------------- // all for silver except where noted Bill Karwin 2009-02-20 11:00:25 Quassnoi 2009-06-01 10:00:16 Greg 2009-10-22 10:00:25 Quassnoi 2009-10-31 10:00:24 // for gold Bill Karwin 2009-11-23 11:00:30 // for gold cletus 2010-01-01 11:00:23 OMG Ponies 2010-01-03 11:00:48 Pascal MARTIN 2010-02-17 11:00:29 Mark Byers 2010-04-07 10:00:35 Daniel Vassallo 2010-05-14 10:00:38 This is consistent with the current list of silver and gold earners at the moment of this writing, but to speak in more timeless terms, as of the end of May 2010 only 2 users have earned the gold [mysql] tag: Quassnoi and Bill Karwin, as evidenced in the above result by their names being the only ones that appear twice. So this is the way I understand it: The first time an Id appears (in chronological order) is for the silver badge The second time is for the gold Now, the above result mixes the silver and gold entries together. My questions are: Is this a typical design, or are there much friendlier schema/normalization/whatever you call it? In the current design, how would you query the silver and gold badges separately? GROUP BY Id and picking the min/max or first/second by the Date somehow? How can you write a query that lists all the silver badges first then all the gold badges next? Imagine also that the "real" query may be more complicated, i.e. not just listing by date. How would you write it so that it doesn't have too many repetition between the silver and gold subqueries? Is it perhaps more typical to do two totally separate queries instead? What is this idiom called? A row "partitioning" query to put them into "buckets" or something?

    Read the article

  • Beginner python - stuck in a loop

    - by Jeremy
    I have two begininer programs, both using the 'while' function, one works correctly, and the other gets me stuck in a loop. The first program is this; num=54 bob = True print('The guess a number Game!') while bob == True: guess = int(input('What is your guess? ')) if guess==num: print('wow! You\'re awesome!') print('but don\'t worry, you still suck') bob = False elif guess>num: print('try a lower number') else: print('close, but too low') print('game over')`` and it gives the predictable output of; The guess a number Game! What is your guess? 12 close, but too low What is your guess? 56 try a lower number What is your guess? 54 wow! You're awesome! but don't worry, you still suck game over However, I also have this program, which doesn't work; #define vars a = int(input('Please insert a number: ')) b = int(input('Please insert a second number: ')) #try a function def func_tim(a,b): bob = True while bob == True: if a == b: print('nice and equal') bob = False elif b > a: print('b is picking on a!') else: print('a is picking on b!') #call a function func_tim(a,b) Which outputs; Please insert a number: 12 Please insert a second number: 14 b is picking on a! b is picking on a! b is picking on a! ...(repeat in a loop).... Can someone please let me know why these programs are different? Thank you!

    Read the article

  • jQuery simplifying code (beginner)

    - by Jonny Wood
    I'm getting to grips with jQuery but find myself repeating code over and over again... Surely there's a simpler way to write this: $('#more-mcr, #more-hilton, #more-lpool').hide(); $('#mcr-hatters').hoverIntent(function() { $('#mcr-hilton').stop().animate({opacity: 0.4}); $('#more-mcr').fadeIn({duration:200}); }, function() { $('#mcr-hilton').stop().animate({opacity: 1}); $('#more-mcr').fadeOut({duration:200}); }); $('#mcr-hilton').hoverIntent(function() { $('#mcr-hatters').stop().animate({opacity: 0.4}); $('#more-hilton').fadeIn({duration:200}); }, function() { $('#mcr-hatters').stop().animate({opacity: 1}); $('#more-hilton').fadeOut({duration:200}); }); $('#lpool-hostel').hoverIntent(function() { $('#more-lpool').fadeIn({duration:200}); }, function() { $('#more-lpool').fadeOut({duration:200}); }); $('#offers-mcr').hoverIntent(function() { $('#offers-lpool').stop().animate({opacity: 0.4}); $('#offers-bham').stop().animate({opacity: 0.4}); }, function() { $('#offers-lpool').stop().animate({opacity: 1}); $('#offers-bham').stop().animate({opacity: 1}); }); $('#offers-lpool').hoverIntent(function() { $('#offers-mcr').stop().animate({opacity: 0.4}); $('#offers-bham').stop().animate({opacity: 0.4}); }, function() { $('#offers-mcr').stop().animate({opacity: 1}); $('#offers-bham').stop().animate({opacity: 1}); }); $('#offers-bham').hoverIntent(function() { $('#offers-lpool').stop().animate({opacity: 0.4}); $('#offers-mcr').stop().animate({opacity: 0.4}); }, function() { $('#offers-lpool').stop().animate({opacity: 1}); $('#offers-mcr').stop().animate({opacity: 1}); }); I'd also like to set the delay for hoverIntent but I don't think this is possible with the way I've written the code currently...?

    Read the article

  • Beginner SQL question: arithmetic with multiple COUNT(*) results

    - by polygenelubricants
    Continuing with the spirit of using the Stack Exchange Data Explorer to learn SQL, (see: Can we become our own “Northwind” for teaching SQL / databases?), I've decided to try to write a query to answer a simple question (on meta): What % of stackoverflow users have over 10,000 rep?. Here's what I've done: Query#1 SELECT COUNT(*) FROM Users WHERE Users.Reputation >= 10000 Result: 556 Query#2 SELECT COUNT(*) FROM USERS Result: 227691 Now, how do I put them together into one query? What is this query idiom called? What do I need to write so I can get, say, a one-row three-column result like this: 556 227691 0,00244190592

    Read the article

  • Simplest possible rack app -> permission error

    - by 7stud
    Here's the program(1.rb) blah blah blah blah blah blah: require 'rack' my_rack = lambda { |env| [200, {}, ["Hello. The time is: #{Time.now}"]] } handler = Rack::Handler::WEBrick handler.run(my_rack, :PORT => 12_500) Here's the error (blah blah blah blah blah): ~/ruby_programs$ ruby 1.rb [2012-12-07 21:49:09] INFO WEBrick 1.3.1 [2012-12-07 21:49:09] INFO ruby 1.9.3 (2012-04-20) [x86_64-darwin10.8.0] [2012-12-07 21:49:09] WARN TCPServer Error: Permission denied - bind(2) [2012-12-07 21:49:09] WARN TCPServer Error: Permission denied - bind(2) /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/utils.rb:85:in `initialize': Permission denied - bind(2) (Errno::EACCES) from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/utils.rb:85:in `new' from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/utils.rb:85:in `block in create_listeners' from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/utils.rb:82:in `each' from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/utils.rb:82:in `create_listeners' from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/server.rb:82:in `listen' from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/server.rb:70:in `initialize' from /Users/7stud/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:45:in `initialize' from /Users/7stud/.rvm/gems/ruby-1.9.3-p194@programming/gems/rack-1.4.1/lib/rack/handler/webrick.rb:10:in `new' from /Users/7stud/.rvm/gems/ruby-1.9.3-p194@programming/gems/rack-1.4.1/lib/rack/handler/webrick.rb:10:in `run' from 1.rb:5:in `<main>' ~/ruby_programs$ Here's line 85 of ../webrick/utils.rb: sock = TCPServer.new(ai[3], port) If I replace the code in 1.rb with this: require 'socket' server = TCPServer.new 12_000 # Server bind to port 2000 loop do client = server.accept # Wait for a client to connect client.puts "Hello !" client.puts "Time is #{Time.now}" client.close end I don't get any errors, and if I enter the address: http://localhost:12000/ in my browser, I get the expected output: Hello ! Time is 2012-12-07 18:58:15 -0700

    Read the article

  • Beginner question: What is binding?

    - by JDelage
    Hi, I was trying to understand the difference between early and late binding, and in the process realized that the concept of binding is nebulous to me. I think I understand that it relates to the way data-as-a-word-of-memory is linked to type-as-a-set-of-language-features but I am not sure those are the right concepts. Also, how does understanding this deeply help people become better programmers? Please note: This question is not "what is late v. early binding" or "what are the trade-offs between the 2". Those already exist here. Thanks, JDelage

    Read the article

  • recommended parser for XML in java(absolute beginner to xml)

    - by poeschlorn
    Hi Pro's, which parser (java) would you recommend for parsing GPX data? Im looking for a one that is very intuitive to use and should not need too much RAM (it seems that DOM requires too much, doesn't it?). I have no idea about parsing xml, so it is time for me to learn this ;-) My documents are not very huge and are always read twice(a point for DOM), but I don't want to keep as few things as possible in RAM. What would you do in this situation? Which one would you coose and why?

    Read the article

  • Android beginner

    - by Karthick
    Hi I am new android. I need to know how to install it in windows xp and which one is the best IDE and what are the requirements are needed. And I need to know how to develop an application in that platform.

    Read the article

  • good beginner tutorial for turbogears 2

    - by coder10
    I find myself struggling to do simple things that would normally take me about 5 minutes to do in PHP. At the moment, I'm trying to create a basic form which will print the details on another page when you click submit. Looking at the documentation, I find examples but none explaining why it works in such a way.

    Read the article

  • doubt about radio button mysql php beginner

    - by Marcelo
    Hi, i'm an engineering student and i'm developing a simple software based on html,php and mysql. I learned this topics on w3schools, i know only the basics. I tired to search about this in this website but I thought the doubts about php,mysql, radio buttons but they were much more complex than I need, and that i could understand. Sorry for the english. (Q1)Ex: $email=$_REQUEST['email'] , in this case the input is text, if it where like a radio button for ex: sex: male or female, how would it be? (Q2) what would be the type of this field (for exemple sex in question 1) in the database: text, int, varchar ? thanks for the attention

    Read the article

  • Beginner having a problem with classes

    - by David
    I'm working through O'Reilly's "Learning Python" and having a problem with classes. I think I understand the concept, but in practice have stumbled upon this problem. Fron page 88-89: >>> class Worker: def __innit__(self, name, pay): self.name=name self.pay=pay def lastName(self): return self.name.split()[-1] def giveRaise(self, percent): self.pay*=(1.0+percent) Then the book says "Calling the class like a function generates instances of a new type ...etc" and gives this example. bob = Worker('Bob Smith', 50000) This gives me this error: TypeError: this constructor takes no arguments. And then I start muttering profanities. So what am I doing wrong here? Thanks for the help.

    Read the article

  • Beginner: Restore previously serialized JFrame-object, how?

    - by elementz
    Hi all. I have managed to serialize my very basic GUI-object containing a JTextArea and a few buttons to a file 'test.ser'. Now, I would like to completely restore the previously saved state from 'test.ser', but seem to have a misconception of how to properly deserialize an objects state. The class MyFrame creates the JFrame and serializes it. Now I tried to deserialize like so: public class Deserialize { static Deserialize ds; MyFrame frame; public static void main(String[] args) { try { ds.deserialize(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void deserialize() throws ClassNotFoundException { try { ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.ser")); frame = (MyFrame) ois.readObject(); ois.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } Maybe somebody could point me into the direction where my misconception is? Thx in advance!

    Read the article

  • Python beginner confused by a complex line of code

    - by Protean
    I understand the gist of the code, that it forms permutations; however, I was wondering if someone could explain exactly what is going on in the return statement. def perm(l): sz = len(l) print (l) if sz <= 1: print ('sz <= 1') return [l] return [p[:i]+[l[0]]+p[i:] for i in range(sz) for p in perm(l[1:])]

    Read the article

  • Python beginner, strange output problem

    - by Protean
    I'm having a weird problem with the following piece of code. from math import sqrt def Permute(array): result1 = [] result2 = [] if len(array) <= 1: return array for subarray in Permute(array[1:]): for i in range(len(array)): temp1 = subarray[:i]+array[0]+subarray[i:] temp2 = [0] for num in range(len(array)-1): temp2[0] += (sqrt(pow((temp1[num+1][1][0]-temp1[num][1][0]),2) + pow((temp1[num+1][1][1]-temp1[num][1][1]),2))) result1.append(temp1+temp2) return result1 a = [['A',[50,1]]] b = [['B',[1,1]]] c = [['C',[100,1]]] array = [a,b,c] result1 = Permute(array) for i in range(len(result1)): print (result1[i]) print (len(result1)) What it does is find all the permutations of the points abc and then returns them along with the sum of the distances between each ordered point. It does this; however, it also seems to report a strange additional value, 99. I figure that the 99 is coming from the computation of the distance between point a and c but I don't understand why it is appearing in the final output as it does.

    Read the article

  • Validating Age field javascript beginner

    - by Marcelo
    Hi people, I'm trying to validate an age field in a form but I'm having some problem. First I tried to make sure that the field will not be send empty. I don't know javascript so I searched some scripts and adapted them to this: function isInteger (s) { var i; if (isEmpty(s)) if (isInteger.arguments.length == 1) return 0; else return (isInteger.arguments[1] == true); for (i = 0; i < s.length; i++) { var c = s.charAt(i); if (!isDigit(c)) return false; } return true; } function isEmpty(s) { return ((s == null) || (s.length == 0)) } function validate_required(field,alerttxt) { with (field) { if (value==null||value=="") { alert(alerttxt);return false; } else { return true; } } } function validate_form(thisform) { with (thisform) { if ((validate_required(age,"Age must be filled out!")==false) || isInteger(age,"Age must be and int number")==false)) {email.focus();return false;} } } //html part <form action="doador.php" onsubmit="return validate_form(this)" method="post"> It's working fine for empty fields, but if I type any letters or characters in age field, it'll be sent and saved a 0 in my database. Can any one help me ? Sorry for any mistake in English, and thanks in andvance for your help.

    Read the article

  • TDD - beginner problems and stumbling blocks

    - by Noufal Ibrahim
    While I've written unit tests for most of the code I've done, I only recently got my hands on a copy of TDD by example by Kent Beck. I have always regretted certain design decisions I made since they prevented the application from being 'testable'. I read through the book and while some of it looks alien, I felt that I could manage it and decided to try it out on my current project which is basically a client/server system where the two pieces communicate via. USB. One on the gadget and the other on the host. The application is in Python. I started off and very soon got entangled in a mess of rewrites and tiny tests which I later figured didn't really test anything. I threw away most of them and and now have a working application for which the tests have all coagulated into just 2. Based on my experiences, I have a few questions which I'd like to ask. I gained some information from http://stackoverflow.com/questions/1146218/new-to-tdd-are-there-sample-applications-with-tests-to-show-how-to-do-tdd but have some specific questions which I'd like answers to/discussion on. Kent Beck uses a list which he adds to and strikes out from to guide the development process. How do you make such a list? I initially had a few items like "server should start up", "server should abort if channel is not available" etc. but they got mixed and finally now, it's just something like "client should be able to connect to server" (which subsumed server startup etc.). How do you handle rewrites? I initially selected a half duplex system based on named pipes so that I could develop the application logic on my own machine and then later add the USB communication part. It them moved to become a socket based thing and then moved from using raw sockets to using the Python SocketServer module. Each time things changed, I found that I had to rewrite considerable parts of the tests which was annoying. I'd figured that the tests would be a somewhat invariable guide during my development. They just felt like more code to handle. I needed a client and a server to communicate through the channel to test either side. I could mock one of the sides to test the other but then the whole channel wouldn't be tested and I worry that I'd miss that. This detracted from the whole red/green/refactor rhythm. Is this just lack of experience or am I doing something wrong? The "Fake it till you make it" left me with a lot of messy code that I later spent a lot of time to refactor and clean up. Is this the way things work? At the end of the session, I now have my client and server running with around 3 or 4 unit tests. It took me around a week to do it. I think I could have done it in a day if I were using the unit tests after code way. I fail to see the gain. I'm looking for comments and advice from people who have implemented large non trivial projects completely (or almost completely) using this methodology. It makes sense to me to follow the way after I have something already running and want to add a new feature but doing it from scratch seems to tiresome and not worth the effort. P.S. : Please let me know if this should be community wiki and I'll mark it like that. Update 0 : All the answers were equally helpful. I picked the one I did because it resonated with my experiences the most. Update 1: Practice Practice Practice!

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >