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  • Need help finding a good curriculum/methodology for self-teaching to program from scratch

    - by BrotherGA2
    My friend and I have both dedicated ourselves to learning the essentials of programming by June of this year from nearly no programming experience. I have done some research and have come to the conclusion that using the Python language will be the best for us, but I am open to suggestions with good reasoning behind them. My motives for learning programming are: Potential Career Path to be able to create programs that can: solve problems; entertain, i.e. useful applications and games. Online college lectures + book (which I am willing to purchase) sounds like a good combination, but I do not know which would be most suitable for me. tl;dr: What I would like to find from the excellent people here is the following: a good, potentially best, programming course and/or book that is well structured and uses good pedagogy so that a person dedicated to learn programming may do so by following its curriculum (or use it to develop a curriculum) over the course of a few months. Thanks! (I apologize if this type of question is not considered proper etiquette, but I haven't found a consensus on this, and would like some guidance beyond the research I've already done)

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  • Partial Classes - are they bad design?

    - by dferraro
    Hello, I'm wondering why the 'partial class' concept even exists in .NET. I'm working on an application and we are reading a (actually very good) book relavant to the development platform we are implementing at work. In the book he provides a large code base /wrapper around the platform API and explains how he developed it as he teaches different topics about the platform development. Anyway, long story short - he uses partial classes, all over the place, as a way to fake multiple inheritence in C# (IMO). Why he didnt just split the classes up into multiple ones and use composition is beyond me. He will have 3 'partial class' files to make up his base class, each w/ 3-500 lines of code... And does this several times in his API. Do you find this justifiable? If it were me, I'd have followed the S.R.P. and created multiple classes to handle different required behaviors, then create a base class that has instances of these classes as members (e.g. composition). Why did MS even put partial class into the framework?? They removed the ability to expand/collapse all code at each scope level in C# (this was allowed in C++) because it was obviously just allowing bad habits - partial class is IMO the same thing. I guess my quetion is: Can you explain to me when there would be a legitimate reason to ever use a partial class? I do not mean this to be a rant / war thread. I'm honeslty looking to learn something here. Thanks

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  • Batch faulting in a to-many relationship for a collection of objects

    - by indragie
    Scenario: Let's say I have an entity called Author that has a to-many relationship called books to the Book entity (inverse relationship author). If I have an existing collection of Author objects, I want to fault in the books relationship for all of them in a single fetch request. Code This is what I've tried so far: NSArray *authors = ... // array of `Author` objects NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Book"]; fetchRequest.returnsObjectsAsFaults = NO; fetchRequest.predicate = [NSPredicate predicateWithFormat:@"author IN %@", authors]; Executing this fetch request does not result in the books relationship of the objects in the authors array being faulted in (inspected via logging). I've also tried doing the fetch request the other way around: NSArray *authors = ... // array of `Author` objects NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Author"]; fetchRequest.returnsObjectsAsFaults = NO; fetchRequest.predicate = [NSPredicate predicateWithFormat:@"SELF IN %@", authors]; fetchRequest.relationshipKeypathsForPrefetching = @[@"books"]; This doesn't fire the faults either. What's the appropriate way of going about doing this?

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  • Parse JSON into a ListView friendly output

    - by Thomas McDonald
    So I have this JSON, which then my activity retrieves to a string: {"popular": {"authors_last_month": [ { "url":"http://activeden.net/user/OXYLUS", "item":"OXYLUS", "sales":"1148", "image":"http://s3.envato.com/files/15599.jpg" }, { "url":"http://activeden.net/user/digitalscience", "item":"digitalscience", "sales":"681", "image":"http://s3.envato.com/files/232005.jpg" } { ... } ], "items_last_week": [ { "cost":"4.00", "thumbnail":"http://s3.envato.com/files/227943.jpg", "url":"http://activeden.net/item/christmas-decoration-balls/75682", "sales":"43", "item":"Christmas Decoration Balls", "rating":"3", "id":"75682" }, { "cost":"30.00", "thumbnail":"http://s3.envato.com/files/226221.jpg", "url":"http://activeden.net/item/xml-flip-book-as3/63869", "sales":"27", "item":"XML Flip Book / AS3", "rating":"5", "id":"63869" }, { ... }], "items_last_three_months": [ { "cost":"5.00", "thumbnail":"http://s3.envato.com/files/195638.jpg", "url":"http://activeden.net/item/image-logo-shiner-effect/55085", "sales":"641", "item":"image logo shiner effect", "rating":"5", "id":"55085" }, { "cost":"15.00", "thumbnail":"http://s3.envato.com/files/180749.png", "url":"http://activeden.net/item/banner-rotator-with-auto-delay-time/22243", "sales":"533", "item":"BANNER ROTATOR with Auto Delay Time", "rating":"5", "id":"22243"}, { ... }] } } It can be accessed here as well, although it because it's quite a long string, I've trimmed the above down to display what is needed. Basically, I want to be able to access the items from "items_last_week" and create a list of them - originally my plan was to have the 'thumbnail' on the left with the 'item' next to it, but from playing around with the SDK today it appears too difficult or impossible to achieve this, so I would be more than happy with just having the 'item' data from 'items_last_week' in the list. Coming from php I'm struggling to use any of the JSON libraries which are available to Java, as it appears to be much more than a line of code which I will need to deserialize (I think that's the right word) the JSON, and they all appear to require some form of additional class, apart from the JSONArray/JSONObject script I have which doesn't like the fact that items_last_week is nested (again, I think that's the JSON terminology) and takes an awful long time to run on the Android emulator. So, in effect, I need a (preferably simple) way to pass the items_last_week data to a ListView. I understand I will need a custom adapter which I can probably get my head around but I cannot understand, no matter how much of the day I've just spent trying to figure it out, how to access certain parts of a JSON string..

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  • What's wrong with this iCalendar event?

    - by rihallix
    I'm generating iCalendar events using PHP. They pass the validation checkers but won't add to Google Calendar or iCalendar. Help - what am I doing wrong? When I attempt to import I get "iCal can't read this calendar file. No events have been added to your calendar. Google just appears to import the calendar but it's not there. BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Foobar Name//NONSGML Foobar Name//EN BEGIN:VEVENT UID:20111129T103025-268Z@foobar DTSTAMP:20111210T103025Z DTSTART:20111210T210000Z DTEND:20111210T230000Z TRANSP: TRANSPARENT SUMMARY:Foobar - Book Fair - text DESCRIPTION: Foobar: Book Fair - text END:VEVENT END:VCALENDAR Should I addslashes or not write colons in my summary or description text? Here are the headers I'm writing out... header("Content-Type: text/Calendar"); header('Content-Disposition: inline; filename="calendar.ics"'); echo "BEGIN:VCALENDAR</br>"; echo "VERSION:2.0</br>"; echo "PRODID:-//$orgname//NONSGML $orgname//EN</br>"; echo "METHOD:REQUEST</p>"; // required by Outlook The file I'm generating has the extension .php (not .ics). Thanks for any insight into what I might be doing wrong. rihallix (PHP5.2 / Windows)

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  • Multiple elements with the same name with SimpleXML and Java

    - by LouieGeetoo
    I'm trying to use SimpleXML to parse an XML document (an ItemLookupResponse for a book from the Amazon Product Advertising API) which contains the following element: <ItemAttributes> <Author>Shane Conder</Author> <Author>Lauren Darcey</Author> <Manufacturer>Pearson Educacion</Manufacturer> <ProductGroup>Book</ProductGroup> <Title>Android Wireless Application Development: Barnes & Noble Special Edition</Title> </ItemAttributes> My problem is that I don't know how to deal with the multiple possible Author elements. Here's what I have right now for the corresponding POJO (Plain Old Java Object), keeping in mind that it's not handling the case of multiple Authors: @Element public class ItemAttributes { @Element public String Author; @Element public String Manufacturer; @Element public String Title; } (I don't care about the ProductGroup, so it's not in the class -- I'm just setting SimpleXML's strict mode to off to allow for that.) I couldn't find an example in the documentation that corresponded with such a case. Using an ElementList with (inline=true) seemed along the right lines, but I didn't see how to do it for String (as opposed to a separate Author class, which I have no need for and don't see how it would even work). Here's a similar question and answer, but for PHP: php - simpleXML how to access a specific element with the same name as others? I don't know what the Java equivalent would be to the accepted answer. Thanks in advance.

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  • Scheme: what are the benefits of letrec?

    - by Ixmatus
    While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

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  • Web Shop Schema - Document Db

    - by Maxem
    I'd like to evaluate a document db, probably mongo db in an ASP.Net MVC web shop. A little reasoning at the beginning: There are about 2 million products. The product model would be pretty bad for rdbms as there'd be many different kinds of products with unique attributes. For example, there'd be books which have isbn, authors, title, pages etc as well as dvds with play time, directors, artists etc and quite a few more types. In the end, I'd have about 9 different products with a combined column count (counting common columns like title only once) of about 70 to 100 whereas each individual product has 15 columns at most. The three commonly used ways in RDBMS would be: EAV model which would have pretty bad performance characteristics and would make it either impractical or perform even worse if I'd like to display the author of a book in a list of different products (think start page, recommended products etc.). Ignore the column count and put it all in the product table: Although I deal with somewhat bigger databases (row wise), I don't have any experience with tables with more than 20 columns as far as performance is concered but I guess 100 columns would have some implications. Create a table for each product type: I personally don't like this approach as it complicates everything else. C# Driver / Classes: I'd like to use the NoRM driver and so far I think i'll try to create a product dto that contains all properties (grouped within detail classes like book details, except for those properties that should be displayed on list views etc.). In the app I'll use BookBehavior / DvdBehaviour which are wrappers around a product dto but only expose the revelent Properties. My questions now: Are my performance concerns with the many columns approach valid? Did I overlook something and there is a much better way to do it in an RDBMS? Is MongoDb on Windows stable enough? Does my approach with different behaviour wrappers make sense?

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  • When to choose which machine learning classifier?

    - by LM
    Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" first choice, and what are the principles for choosing that one? Examples of the type of answers I'm looking for (from Manning et al.'s "Introduction to Information Retrieval book": http://nlp.stanford.edu/IR-book/html/htmledition/choosing-what-kind-of-classifier-to-use-1.html): a. If your data is labeled, but you only have a limited amount, you should use a classifier with high bias (for example, Naive Bayes). [I'm guessing this is because a higher-bias classifier will have lower variance, which is good because of the small amount of data.] b. If you have a ton of data, then the classifier doesn't really matter so much, so you should probably just choose a classifier with good scalability. What are other guidelines? Even answers like "if you'll have to explain your model to some upper management person, then maybe you should use a decision tree, since the decision rules are fairly transparent" are good. I care less about implementation/library issues, though. Also, for a somewhat separate question, besides standard Bayesian classifiers, are there 'standard state-of-the-art' methods for comment spam detection (as opposed to email spam)? [Not sure if stackoverflow is the best place to ask this question, since it's more machine learning than actual programming -- if not, any suggestions for where else?]

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  • How do I send text to a UITextView?

    - by Lee
    I'm new to iphone development. I'm a VB programmer who is trying to convert a VB application to an ipad app. I need some help with sending text to a UITextView. I want to first have a UIPickerView and then once the user hits a UIButton, a UITextView appears and the text is then generated by my source code code, line by line. The code would constantly be concatenating strings to the text. It would sort of go like this-- 1) User makes selections with UIPickerView. 2) User then hits UIButton. 3) UIPickerView is replaced on the screen with a UITextView. 4) The code does stuff. 5) The code adds the 1st line of text into the UITextView. 6) The code does more stuff. 7) The code then adds the 2nd line of text into the UITextView, retaining the 1st line that was already there. Steps 6 and 7 are repeated until the code is done. Does anyone know of any examples of this that I could look at? I am mostly interested in finding something like a youtube video, a webpage that explains the code or even a good book that covers this particular topic. I am finding that the sample codes that Apple has on this site goes over my head. In fact, I could probably benefit from a good book. But, I am looking for one that I would already know covers this particular topic, since it is so essential to the app that I am trying to build.

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  • Newbie question: undefined local variable or method , why??

    - by Mellon
    I am new in Rails (I am using Rails 3.0.3), currently I am following the book "Agile Web Development with Rails" to develop a simple rails application. I followed the book to: --create a model 'Cart' class; --implement 'add_to_cart' method in my 'store_controller', I have a line of code <%=button_to "Add to Cart", :action => add_to_cart, :id => product %> in my /store/index.html.erb As you see, there is :action => add_to_cart in my index.html.erb, which will invoke the add_to_cart method in my *Controllers/store_controller.rb* But after I refresh the browser, I got the error "undefined local variable or method 'add_to_cart'", apparently I do have the method add_to_cart in my 'store_controller.rb', why I got this error??? What is the possible cause??? Here are my codes: store_controller.rb class StoreController < ApplicationController def index @products = Product.find_products_for_sale end def add_to_cart product = Product.find(params[:id]) @cart = find_cart @cart.add_product(product) end private def find_cart session[:cart] ||= Cart.new end end /store/index.html.erb <h1>Your Pragmatic Catalog</h1> <% @products.each do |product| -%> <div class="entry"> <%= image_tag(product.image_url) %> <h3><%=h product.title %></h3> <%= product.description %> <div class="price-line"> <span class="price"><%= number_to_currency(product.price) %></span> <!-- START_HIGHLIGHT --> <!-- START:add_to_cart --> **<%= button_to 'Add to Cart', :action => 'add_to_cart', :id => product %>** <!-- END:add_to_cart --> <!-- END_HIGHLIGHT --> </div> </div> <% end %> Model/cart.rb class Cart attr_reader :items def initialize @items = [] end def add_product(product) @items << product end end

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  • stackoverflow tags and related tags

    - by parminder
    Hi Experts, I am working on a website where a user can add tags to their posted books. It is similar to stackover flow, but I am keeping my tags in differnt table. so here are the tables/class in linq to entities. Books { bookId, Title } Tags { Id Tag } BooksTags { Id BookId TagId } Here are few sample records. Books BookId Title 113421 A 113422 B Tags Id Tag 1 ASP 2 C# 3 CSS 4 VB 5 VB.NET 6 PHP 7 java 8 pascal BooksTags Id BookId TagId 1 113421 1 2 113421 2 3 113421 3 4 113421 4 5 113422 1 6 113422 4 7 113422 8 Question 1 : I need to write something in linq to entities queries which gives me data according to the tags say if I want bookIds where tagid =1 it should return bookid 113421 and 113422 as it exists in both the books, but If I ask data for tags 1 and 2 it should return only book 113421 as that is the only book where both the tags are present. Question 2 : I need tags and their count too to show in related tags, so in first case my related tags class should have following result. RelatedTags Tag Count 2 1 3 1 4 2 8 1 in the second case when two tags are requested the result should be like RelatedTags Tag Count 3 1 4 1 I have get the first thing working by converting a sql query in linqer, but that seems like a hell. so want to know if there is any better idea. I have used dyanmic where clause to include two tags. So if someone can help. It will be much appreciated. Thanks Parminder

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  • Question about decorator pattern and the abstract decorator class?

    - by es11
    This question was asked already here, but rather than answering the specific question, descriptions of how the decorator pattern works were given instead. I'd like to ask it again because the answer is not immediately evident to me just by reading how the decorator pattern works (I've read the wikipedia article and the section in the book Head First Design Patterns). Basically, I want to know why an abstract decorator class must be created which implements (or extends) some interface (or abstract class). Why can't all the new "decorated classes" simply implement (or extend) the base abstract object themselves (instead of extending the abstract decorator class)? To make this more concrete I'll use the example from the design patterns book dealing with coffee beverages: There is an abstract component class called Beverage Simple beverage types such as HouseBlend simply extend Beverage To decorate beverage, an abstract CondimentDecorator class is created which extends Beverage and has an instance of Beverage Say we want to add a "milk" condiment, a class Milk is created which extends CondimentDecorator I'd like to understand why we needed the CondimentDecorator class and why the class Milk couldn't have simply extended the Beverage class itself and been passed an instance of Beverage in its constructor. Hopefully this is clear...if not I'd simply like to know why is the abstract decorator class necessary for this pattern? Thanks. Edit: I tried to implement this, omitting the abstract decorator class, and it seems to still work. Is this abstract class present in all descriptions of this pattern simply because it provides a standard interface for all of the new decorated classes?

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  • Handles Comparison: empty classes vs. undefined classes vs. void*

    - by Nawaz
    Microsoft's GDI+ defines many empty classes to be treated as handles internally. For example, (source GdiPlusGpStubs.h) //Approach 1 class GpGraphics {}; class GpBrush {}; class GpTexture : public GpBrush {}; class GpSolidFill : public GpBrush {}; class GpLineGradient : public GpBrush {}; class GpPathGradient : public GpBrush {}; class GpHatch : public GpBrush {}; class GpPen {}; class GpCustomLineCap {}; There are other two ways to define handles. They're, //Approach 2 class BOOK; //no need to define it! typedef BOOK *PBOOK; typedef PBOOK HBOOK; //handle to be used internally //Approach 3 typedef void* PVOID; typedef PVOID HBOOK; //handle to be used internally I just want to know the advantages and disadvantages of each of these approaches. One advantage with Microsoft's approach is that, they can define type-safe hierarchy of handles using empty classes, which (I think) is not possible with the other two approaches. What else? EDIT: One advantage with the second approach (i.e using incomplete classes) is that we can prevent clients from dereferencing the handles (that means, this approach appears to support encapsulation strongly, I suppose). The code would not even compile if one attempts to dereference handles. What else?

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  • Want to display a 3D model on the iPhone: how to get started?

    - by JeremyReimer
    I want to display and rotate a single 3D model, preferably textured, on the iPhone. Doesn't have to zoom in and out, or have a background, or anything. I have the following: an iPhone a MacBook the iPhone SDK Blender My knowledge base: I can make 3D models in various 3D programs (I'm most comfortable with 3D Studio Max, which I once took a course on, but I've used others) General knowledge of procedural programming from years ago (QuickBasic - I'm old!) Beginner's knowledge of object-oriented programming from going through simple Java and C# tutorials (Head Start C# book and my wife's intro to OOP course that used Java) I have managed to display a 3D textured model and spin it using a tutorial in C# I got off the net (I didn't just copy and paste, I understand basically how it works) and the XNA game development library, using Visual Studio on Windows. What I do not know: Much about Objective C Anything about OpenGL or OpenGL ES, which the iPhone apparently uses Anything about XCode My main problem is that I don't know where to start! All the iPhone books I found seem to be about creating GUI applications, not OpenGL apps. I found an OpenGL book but I don't know how much, if any, applies to iPhone development. And I find the Objective C syntax somewhat confusing, with the weird nested method naming, things like "id" that don't make sense, and the scary thought that I have to do manual memory management. Where is the best place to start? I couldn't find any tutorials for this sort of thing, but maybe my Google-Fu is weak. Or maybe I should start with learning Objective C? I know of books like Aaron Hillgrass', but I've also read that they are outdated and much of the sample code doesn't work on the iPhone SDK, plus it seems geared towards the Model-View-Controller paradigm which doesn't seem that suited for 3D apps. Basically I'm confused about what my first steps should be.

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  • Kernighan & Ritchie word count example program in a functional language

    - by Frank
    I have been reading a little bit about functional programming on the web lately and I think I got a basic idea about the concepts behind it. I'm curious how everyday programming problems which involve some kind of state are solved in a pure functional programing language. For example: how would the word count program from the book 'The C programming Language' be implemented in a pure functional language? Any contributions are welcome as long as the solution is in a pure functional style. Here's the word count C code from the book: #include <stdio.h> #define IN 1 /* inside a word */ #define OUT 0 /* outside a word */ /* count lines, words, and characters in input */ main() { int c, nl, nw, nc, state; state = OUT; nl = nw = nc = 0; while ((c = getchar()) != EOF) { ++nc; if (c == '\n') ++nl; if (c == ' ' || c == '\n' || c = '\t') state = OUT; else if (state == OUT) { state = IN; ++nw; } } printf("%d %d %d\n", nl, nw, nc); }

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  • Learning C++ as a Perl programmer

    - by meneldor
    Hello all, I'm a Perl5 programmer for 7 years and I'm trying to learn C++ now. Some of the c++ syntax is hard for me to understand and to think in c++ way. For example: In perl you can mix the data in the arrays @array = (1,"string",5.355); You can assign any value to a scalar variable: $var = 1; $var = "string"; $var = \$reference_to_scalar; There are many examples. The friend of mine recommend me the book "Thinking of C++" by Bruce Eckel, but I haven't any C background and it's hard for me to understand some things. So my question is - could you recommend me a book for this situation. I don't want to learn C. I understand OOP (I'm getting more familiar with C++ oop aswell), I understand the point of the pointers(and some arithmetic) and references(widely used in perl). I dont need some of the manuals for dummies (what is int,bool,double,if,while), I just need a direction how to learn C++ from my point of perl programmer, because I,m sure that there are many like me. Thank you in advance.

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  • Learning libraries without books or tutorials

    - by Kawili-wili
    While many ask questions about where to find good books or tutorials, I'd like to take the opposite tack. I consider myself to be an entry-level programmer ready to move up to mid-level. I have written code in c, c++, c#, perl, python, clojure, vb, and java, so I'm not completely clueless. Where I see a problem in moving to the next level is learning to make better use of the literally hundreds upon hundreds of libraries available out there. I seem paralyzed unless there is a specific example in a book or tutorial to hand-hold me, yet I often read in various forums where another programmer attempts to assist with a question. He/she will look through the docs or scan the available classes/methods in their favorite IDE and seem to grok what's going on in a relatively short period of time, even if they had no previous experience with that specific library or function. I yearn to break the umbilical chord of constantly spending hour upon hour searching and reading, searching and reading, searching and reading. Many times there is no book or tutorial, or if there is, the discussion glosses over my specific needs or the examples shown are too far off the path for the usage I had in mind or the information is outdated and makes use of deprecated components or the library itself has fallen out of mainstream, yet is still perfectly usable (but no docs, books, or tutorials to hand-hold). My question is: In the absence of books or tutorials, what is the best way to grok new or unfamiliar libraries? I yearn to slicken the grok path so I can get down to the business of doing what I love most -- coding.

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  • How do I update a NSTableView when its data source has changed?

    - by Jergason
    I am working along with Cocoa Programming For Mac OS X (a great book). One of the exercises the book gives is to build a simple to-do program. The UI has a table view, a text field to type in a new item and an "Add" button to add the new item to the table. On the back end I have a controller that is the data source and delegate for my NSTableView. The controller also implements an IBAction method called by the "Add" button. It contains a NSMutableArray to hold the to do list items. When the button is clicked, the action method fires correctly and the new string gets added to the mutable array. However, my data source methods are not being called correctly. Here they be: - (NSInteger)numberOfRowsInTableView:(NSTableView *)aTableView { NSLog(@"Calling numberOfRowsInTableView: %d", [todoList count]); return [todoList count]; } - (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex { NSLog(@"Returning %@ to be displayed", [todoList objectAtIndex:rowIndex]); return [todoList objectAtIndex:rowIndex]; } Here is the rub. -numberOfRowsInTableView only gets called when the app first starts, not every time I add something new to the array. -objectValueForTableColumn never gets called at all. I assume this is because Cocoa is smart enough to not call this method when there is nothing to draw. Is there some method I need to call to let the table view know that its data source has changed, and it should redraw itself?

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  • Learning Java, how to type text on canvas?

    - by Voley
    I'm reading a book by Eric Roberts - Art and science of java and it got an excersise that I can't figure out - You have to make calendar, with GRect's, 7 by 6, that goes ok, the code part is easy, but also you have to type the numbers of the date on those rectangles, and it's kinda hard for me, there is nothing about it in the book. I tried using GLabel thing, but here arises the problem that I need to work on those numbers, and it says "can't convert from int to string and vice versa". GLabel (string, posX, posY) - it is not accepting int as a parameter, only string, I even tried typecasting, still not working. For example I want to make a loop int currentDate = 1; while (currentDate < 31) { add(new Glabel(currentDate, 100, 100); currentDate++; This code is saying that no man, can't convert int to string. If i try changing currentDate to string, it works, but I got a problem with calculation, as I can't manipulate with number in string, it doesn't even allow to typecast it into int. How can I fix it? Maybe there is another class or method to type the text over those rectangles? I know about println but it doen't have any x or y coordinates, so I can't work with it. And I think it's only for console programs.

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  • Pro ASP.Net MVC 3 Entity Framework Sports Store tutorial

    - by gary7
    Following the tutorial in the book "Pro ASP.Net MVC 3 Entity Framework" in Chapter 9 - Image Uploads section; asks that the Product class be updated with two new columns - public byte ImageData, and public string ImageType. It also directs that the database be updated with these two columns via the server explorer. After these updates, the discussion directs that the Entity Framework Conceptual Model be updated via the SportsStore.EDMX file. This file does not exist in the source code for the project, and was not used in the project to begin with. Obvious errata for the book. Adding the ADO.NET Entity Data Model to the Project then overrides the EFProduct reposistory (conceptual model used throughout the project) which inherits from the interface IProductsRepository; and results in errors within the mapping. If the project is debugged after the columns are added, an error is thrown related to the new added columns. Has anyone resolved this issue in the project? I haven't found any solutions so far. Thanks!

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  • Is there a programmatic way to transform a sequence of image files into a PDF?

    - by Salim Fadhley
    I have a sequence of JPG images. Each of the scans is already cropped to the exact size of one page. They are sequential pages of a valuable and out of print book. The publishing application requires that these pages be submitted as a single PDF file. I could take each of these images and just past them into a word-processor (e.g. OpenOffice) - unfortunately the problem here is that it's a very big book and I've got quite a few of these books to get through. It would obviously be time-consuming. This is volunteer work! My second idea was to use LaTeX - I could make a very simple document that consists of nothing more than a series of in-line image includes. I'm sure that this approach could be made to work, it's just a little on the complex side for something which seems like a very simple job. It occurred to me that there must be a simpler way - so any suggestions? I'm on Ubuntu 9.10, my primary programming language is Python, but if the solution is super-simple I'd happily adopt any technology that works.

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  • Basic problems (type inference or something else?) in Objective-C/Cocoa.

    - by Matt
    Hi, Apologies for how basic these questions are to some. Just started learning Cocoa, working through Hillegass' book, and am trying to write my first program (a GUI Cocoa app that counts the number of characters in a string). I tried this: NSString *string = [textField stringValue]; NSUInteger *stringLength = [string length]; NSString *countString = (@"There are %u characters",stringLength); [label setStringValue:countString]; But I'm getting errors like: Incompatible pointer conversion initializing 'NSUInteger' (aka 'unsigned long'), expected 'NSUInteger *'[-pedantic] for the first line, and this for the second line: Incompatible pointer types initializing 'NSUInteger *', expected 'NSString *' [-pedantic] I did try this first, but it didn't work either: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] On a similar note, I've only written in easy scripting languages before now, and I'm not sure when I should be allocing/initing objects and when I shouldn't. For example, when is it okay to do this: NSString *myString = @"foo"; or int *length = 5; instead of this: NSString *myString = [[NSString alloc] initWithString:"foo"]; And which ones should I be putting into the header files? I did check Apple's documentation, and CocoaDev, and the book I'm working for but without luck. Maybe I'm looking in the wrong places.. Thanks to anyone who takes the time to reply this: it's appreciated, and thanks for being patient with a beginner. We all start somewhere. EDIT Okay, I tried the following again: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] And it actually worked this time. Not sure why it didn't the first time, though I think I might have typed %d instead of %u by mistake. However I still don't understand why the code I posted at the top of my original post doesn't work, and I have no idea what the errors mean, and I'd very much like to know because it seems like I'm missing something important there.

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  • [LaTeX] positions of page numbers, position of chapter headings, chapters AND Table of Contents, Ref

    - by kaikanmonaco
    I am writing my PhD thesis (120+ pages) in latex, the deadline is approaching and I am struggling with layout problems. I am using the documentstyle book. I am posting both problems in this one thread because I am not sure if the solution might be related to both problems or not. Problems are: 1.) The page numbers are mostly located on the top-right of each page (this is correct and where I want them to be). However, only on the first page of chapters and on the first page of what I call "special chapters", the page number is located bottom-centered. With "special chapters" I mean: List of Contents, List of Figures, List of Tables, References, Index. My university will not accept the thesis like this. The page number must ALWAYS be top-right one each page, even if the page is the first page of a chapter or the first page of something like the List of Contents. How can I fix this? 2.) On the first page of chapters and "special chapters" (List of Contents...), the chapter title is located far too low on the page. This is the standard layout of LaTeX with documentstyle book I think. However, the chapter title must start at the very top of the page! I.e. the same height as the normal text on the pages that follow. I mean the chapter title, not the header. I.e., if there is a chapter called "Chapter 1 Dynamics of foobar under mechanical stress" then that text has to start from the top the page, but right now it starts several centimeters below the top. How can I fix this? Have tried all kinds of things to no effect, I'd be very thankful for a solution! Thanks.

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  • How do i set the Transaction Isolation in EJB?

    - by Nitesh Panchal
    Hello, I am not able to find a way to set TransactionIsolation in ejb. Can anybody tell me how do i set it? I am using persistence. I have looked the following classes : EntityManager , EntityManagerFactory, UserTransaction. None of them seems to have any method like setTransactionIsolation or such. Do we need to change persistence.xml? I just read a book named Mastering EJB 3.0 4th edition. They gave a full 10 page theory about Isolation level that this problems occur and that occurs and such things but at the end they gave this paragraph :- "As we now know, the EJB standard does not deal with isolation levels directly, and rightly so. EJB is a component specification. It defines the behavior and contracts of a business component with clients and middleware infrastructure (containers) such that the component can be rendered as various middleware services properly. EJBs therefore are transactional components that interact with resource managers, such as the JDBC resource manager or JMS resource manager, via JTS, as part of a transaction. They are not, hence, resource components in themselves. Since isolation levels are very specific to the behavior and capabilities of the underlying resources, they should therefore be specified at the resource API levels. " What exactly does it mean? What is meant by resource level APIs? Please help me. If persistence has no way to set Isolation Level then why do they give such huge theory in an EJB book and make it heavy in weight unnecessarily :(

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