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  • Why do I not get the correct answer for Euler 56 in J?

    - by Gregory Higley
    I've solved 84 of the Project Euler problems, mostly in Haskell. I am now going back and trying to solve in J some of those I already solved in Haskell, as an exercise in learning J. Currently, I am trying to solve Problem 56. Let me stress that I already know what the right answer is, since I've already solved it in Haskell. It's a very easy, trivial problem. I will not give the answer here. Here is my solution in J: digits =: ("."0)":"0 eachDigit =: adverb : 'u@:digits"0' NB. I use this so often I made it an adverb. cartesian =: adverb : '((#~ #) u ($~ ([:*~#)))' >./ +/ eachDigit x: ^ cartesian : i. 99 This produces a number less than the desired result. In other words, it's wrong somehow. Any J-ers out there know why? I'm baffled, since it's pretty straightforward and totally brute force.

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  • Basic Array Iteration in Ruby

    - by michaelmichael
    What's a better way to traverse an array while iterating through another array? For example, if I have two arrays like the following: names = [ "Rover", "Fido", "Lassie", "Calypso"] breeds = [ "Terrier", "Lhasa Apso", "Collie", "Bulldog"] Assuming the arrays correspond with one another - that is, Rover is a Terrier, Fido is a Lhasa Apso, etc. - I'd like to create a dog class, and a new dog object for each item: class Dog attr_reader :name, :breed def initialize(name, breed) @name = name @breed = breed end end I can iterate through names and breeds with the following: index = 0 names.each do |name| dog = Dog.new("#{name}", "#{breeds[index]}") index = index.next end However, I get the feeling that using the index variable is the wrong way to go about it. What would be a better way?

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  • SQLiteDataAdapter Update method returning 0

    - by Lirik
    I loaded 83 rows from my CSV file, but when I try to update the SQLite database I get 0 rows... I can't figure out what I'm doing wrong. The program outputs: Num rows loaded is 83 Num rows updated is 0 The source code is: public void InsertData(String csvFileName, String tableName) { String dir = Path.GetDirectoryName(csvFileName); String name = Path.GetFileName(csvFileName); using (OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + dir + @";Extended Properties=""Text;HDR=Yes;FMT=Delimited""")) { conn.Open(); using (OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM " + name, conn)) { QuoteDataSet ds = new QuoteDataSet(); adapter.Fill(ds, tableName); Console.WriteLine("Num rows loaded is " + ds.Tags.Rows.Count); InsertData(ds, tableName); } } } public void InsertData(QuoteDataSet data, String tableName) { using (SQLiteConnection conn = new SQLiteConnection(_connectionString)) { using (SQLiteDataAdapter sqliteAdapter = new SQLiteDataAdapter("SELECT * FROM " + tableName, conn)) { using (new SQLiteCommandBuilder(sqliteAdapter)) { conn.Open(); Console.WriteLine("Num rows updated is " + sqliteAdapter.Update(data, tableName)); } } } } Any hints on why it's not updating the correct number of rows?

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  • Learning Lisp - Why ?

    - by David
    I really feel that I should learn Lisp and there are plenty of good resources out there to help me do it. I'm not put off by the complicated syntax, but where in "traditional commercial programming" would I find places it would make sense to use it instead of a procedural language. Is there a commercial killer-app out there that's been written in Lisp ?

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  • How should a programmer go about getting started with Flash/Flex/ActionScript?

    - by Graphics Noob
    What is the shortest path between zero (ie no flash related development software on my computer or information about where to obtain it or get started) to running a "hello world" ActionScript? I'm hoping for an answer that gives step by step instructions about exactly what software is needed to get started, an example of some "hello world" code, and instructions for compiling and running the code. I've spent more time than I think should be necessary researching this question and not found much information. Hopefully this question will be found by programmers like me who want to get started with Flash/Flex/ActionScript (After my morning of researching I still don't even know what terminology to use so I'll just throw it all out there). ActionScript tutorials I've found are focused on programming concepts, ie logic, branching, OOP, etc, and some even have code examples to download, but not a single one I've found explains how to compile and run the code. They all seem to assume you have an IDE standing by but no knowledge of programming, exactly the opposite of the position I'm in. Here are the most related SO questions I've found: http://stackoverflow.com/questions/59083/what-is-adobe-flex-is-it-just-flash-ii http://stackoverflow.com/questions/554899/getting-started-with-flex-3-ui-actionscript-programming http://stackoverflow.com/questions/2123105/how-to-learn-flex

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  • What is the single most influential book every programmer should read?

    - by NotMyself
    If you could go back in time and tell yourself to read a specific book at the beginning of your career as a developer, which book would it be? I expect this list to be varied and to cover a wide range of things. For me, the book would be Code Complete. After reading that book, I was able to get out of the immediate task mindset and begin to think about the bigger picture, quality and maintainability.

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  • So do programming languages get updated regularly like everyday applications or are they just x.0 re

    - by Randy
    I was wondering if programming languages and frameworks get updated in small increments or are they just x.0 releases? And if they do how do you keep up on all the changes in every update? I am specifically interested in Objective-C and Cocoa and CocoaTouch. I'm learning from books and online PDF's etc, but often they are at best a few years old. I just would like to know if there have been any changes etc. that should concern me and even if not, inevitably there will be, so where can I look out for them?

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  • Codeigniter: Checklist for new users & logistics of app

    - by Kevin Brown
    I'm developing my first web-app, and I'm working through logistics. New users (At first login) need to complete a few things before they can use the app fully. For example, they need to complete their profile before they can move on to step 2, which is taking a test. What's the best way to go about creating a "new-user" checklist? I want it to be as simple as possible, coding wise, and as easy as possible for the user.

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  • Strange Bubble sort behaviour.

    - by user271528
    Can anyone explain why this bubble sort function doesn't work and why I loose number in my output. I'm very new to C, so please forgive me if this is something very obvious I have missed. #include <stdio.h> #include int bubble(int array[],int length) { int i, j; int temp; for(i = 0; i < (length); ++i) { for(j = 0; j < (length - 1); ++j) { if(array[i] array[i+1]) { temp = array[i+1]; array[i+1] = array[i]; array[i] = temp; } } } return 0; } int main() { int array[] = {12,234,3452,5643,0}; int i; int length; length = (sizeof(array)/sizeof(int)); printf("Size of array = %d\n", length); bubble(array, length); for (i = 0; i < (length); ++i) { printf("%d\n", array[i]); } return 0; } Output Size of array = 5 12 234 3452 0 0

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  • How to get the original variable name of variable passed to a function

    - by Acorn
    Is it possible to get the original variable name of a variable passed to a function? E.g. foobar = "foo" def func(var): print var.origname So that: func(foobar) Returns: >>foobar EDIT: All I was trying to do was make a function like: def log(soup): f = open(varname+'.html', 'w') print >>f, soup.prettify() f.close() .. and have the function generate the filename from the name of the variable passed to it. I suppose if it's not possible I'll just have to pass the variable and the variable's name as a string each time.

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  • Linking IronPython to WPF

    - by DonnyD
    I just installed VS2010 and the great new IronPython Tools extension. Currently this extension doesn't yet generate event handlers in code upon double-clicking wpf visual controls. Is there anyone that can provide or point me to an example as to how to code wpf event handlers manually in python. I've had no luck finding any and I am new to visual studio. Upon generating a new ipython wpf project the auto-generated code is: import clr clr.AddReference('PresentationFramework') from System.Windows.Markup import XamlReader from System.Windows import Application from System.IO import FileStream, FileMode app = Application() app.Run(XamlReader.Load(FileStream('WpfApplication7.xaml', FileMode.Open))) and the XAML is: <Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="WpfApplication7" Height="300" Width="300"> <Button>Click Me</Button> </Window> Any help would be appreciated.

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  • python regex of a date in some text, enclosed by two keywords

    - by Horace Ho
    This is Part 2 of this question and thanks very much for David's answer. What if I need to extract dates which are bounded by two keywords? Example: text = "One 09 Jun 2011 Two 10 Dec 2012 Three 15 Jan 2015 End" Case 1 bounding keyboards: "One" and "Three" Result expected: ['09 Jun 2011', '10 Dec 2012'] Case 2 bounding keyboards: "Two" and "End" Result expected: ['10 Dec 2012', '15 Jan 2015'] Thanks!

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  • How can I generate the Rowland prime sequence idiomatically in J?

    - by Gregory Higley
    If you're not familiar with the Rowland prime sequence, you can find out about it here. I've created an ugly, procedural monadic verb in J to generate the first n terms in this sequence, as follows: rowland =: monad define result =. 0 $ 0 t =. 1 $ 7 while. (# result) < y do. a =. {: t n =. 1 + # t t =. t , a + n +. a d =. | -/ _2 {. t if. d > 1 do. result =. ~. result , d end. end. result ) This works perfectly, and it indeed generates the first n terms in the sequence. (By n terms, I mean the first n distinct primes.) Here is the output of rowland 20: 5 3 11 23 47 101 7 13 233 467 941 1889 3779 7559 15131 53 30323 60647 121403 242807 My question is, how can I write this in more idiomatic J? I don't have a clue, although I did write the following function to find the differences between each successive number in a list of numbers, which is one of the required steps. Here it is, although it too could probably be refactored by a more experienced J programmer than I: diffs =: monad : '}: (|@({.-2&{.) , $:@}.) ^: (1 < #) y'

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  • GoTo statements, and alternatives (help me please im new) (VB.net)

    - by qais
    Basically I posted a code snippet on a forum asking for help and people pointed out to me that using GoTo statements is very bad programming practise so I'm just wondering, why is it bad? And also what alternative is there to use, like for example in this program ive done for homework the user has to input their date of birth and if the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if theres any better way to do this i'd appreciate if you could tell me that also :D) then how would i be able to loop back to ask them again? heres a little extract of my code retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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  • Need to add underscore to my regex

    - by TaMeR
    I suck at regular expression and just can't seem to figure this out. '/^[A-Za-z0-9](?:.[A-Za-z0-9]+)*$/' As it's right now it allows dots anytime after the first char and I like to add _ so that it allows both. Thanks

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  • Comparing a time delta in python

    - by Alpesh Patel
    I have a variable which is <type 'datetime.timedelta'> and I would like to compare it against certain values. Lets say d produces this datetime.timedelta value 0:00:01.782000 I would like to compare it like this: #if d is greater than 1 minute if d>1:00: print "elapsed time is greater than 1 minute" I have tried converting datetime.timedelta.strptime() but that does seem to work. Is there an easier way to compare this value?

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  • Free Fall Question

    - by Makenshi
    ok im gonna try my best to explain my problem i have this program where u can select 5 balls when u select one you can take it with you while you have the mouse button pressed and its within the ball radius. The problem is that i need a way to make the ball go up when the user stop pressing the mouse button like he sent it to float in the air then make it fall down again i have one way to know the time,velocity and thus the acceleration but i dont know how to implement it... right now i have this void Circulo::caida(float velocidad,float tiempo) { if(this->posY >= 580) { this->posY = 580; this->vcaida = 0.0f; } else if(this->posY < 580) { //this->distancia=9.81f * 0.5f*tiempo*tiempo; this->vcaida += velocidad; this->posY += this->vcaida; } } with this like this it just falls and i cant make the effect i tried to explain... thank you i hope someone can help me .< oh yeah im calculating the time like this just in case it helps difX=(x> evento.motion.xrel)? x-evento.motion.xrel : evento.motion.xrel-x; difY=(y> evento.motion.yrel)? y-evento.motion.yrel : evento.motion.yrel-y; and im sending difY as the time variable

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  • How does PHP work - literature

    - by Ondrej Slinták
    I'm interested in literature (articles on internet, in magazines, books, podcasts - I don't really mind anything) that describes how PHP works internally, about its gotchas and perhaps some advanced functions. Is there anything like this out there? I tried to search on Google, but majority of articles were about starting with PHP and its basic functions. Any input is really welcome as I'm trying to understand the language internally - I'm tired of my mindless typing of code without understanding its essence.

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  • How to retrieve Directories size including all sub-directories?

    - by vikingosegundo
    I have stored images from the net like this Documents/imagecache/domain1/original/path/inURI/foo.png Documents/imagecache/domain2/original/path/inURI/bar.png Documents/imagecache/... Documents/imagecache/... Now I'd like to check the size of imagecache including all it sub-directories. Is there a convenient way of doing it — preferable without crawling through all the data manually?

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  • Codeigniter: db data in controller

    - by Kevin Brown
    I'm confused about what to do... I'm working on a user's page where they can view certain things only if their supervisor has given them "money" or "credits". I need a simple way to get the person that is their supervisor by doing something like: $data['employer'] = $this->home_model->getEmployees(array('user_id'=>$manager_id)); Basically, get the user information about a person who's user_id matches the manager_id of the currently logged in member. I don't know how to set the variable $manager_id. Additional Information: The current user has an id, and a manager_id. I need the id of the manager. So, I need to grab the manager_id of the logged-in user and find the manager who's user_id is that of the manager_id. What's the process to do this? I can get each individually, but I don't know how to use one to get the other... I know it is confusing, but I'm confused! Thanks for the help!

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