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  • Convert List of one type to Array of another type using Dozer

    - by aheu
    I'm wondering how to convert a List of one type to an array of another type in Java using Dozer. The two types have all the same property names/types. For example, consider these two classes. public class A{ private String test = null; public String getTest(){ return this.test } public void setTest(String test){ this.test = test; } } public class B{ private String test = null; public String getTest(){ return this.test } public void setTest(String test){ this.test = test; } } I've tried this with no luck. List<A> listOfA = getListofAObjects(); Mapper mapper = DozerBeanMapperSingletonWrapper.getInstance(); B[] bs = mapper.map(listOfA, B[].class); I've also tried using the CollectionUtils class. CollectionUtils.convertListToArray(listOfA, B.class) Neither are working for me, can anyone tell me what I am doing wrong? The mapper.map function works fine if I create two wrapper classes, one containing a List and the other a b[]. See below: public class C{ private List<A> items = null; public List<A> getItems(){ return this.items; } public void setItems(List<A> items){ this.items = items; } } public class D{ private B[] items = null; public B[] getItems(){ return this.items; } public void setItems(B[] items){ this.items = items; } } This works oddly enough... List<A> listOfA = getListofAObjects(); C c = new C(); c.setItems(listOfA); Mapper mapper = DozerBeanMapperSingletonWrapper.getInstance(); D d = mapper.map(listOfA, D.class); B[] bs = d.getItems(); How do I do what I want to do without using the wrapper classes (C & D)? There has got to be an easier way... Thanks!

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  • how to set Content-Type automatically when i download the data that i uploaded.

    - by zjm1126
    this is my code : import os from google.appengine.ext import webapp from google.appengine.ext.webapp import template from google.appengine.ext.webapp.util import run_wsgi_app from google.appengine.ext import db #from login import htmlPrefix,get_current_user class MyModel(db.Model): blob = db.BlobProperty() class BaseRequestHandler(webapp.RequestHandler): def render_template(self, filename, template_args=None): if not template_args: template_args = {} path = os.path.join(os.path.dirname(__file__), 'templates', filename) self.response.out.write(template.render(path, template_args)) class upload(BaseRequestHandler): def get(self): self.render_template('index.html',) def post(self): file=self.request.get('file') obj = MyModel() obj.blob = db.Blob(file.encode('utf8')) obj.put() self.response.out.write('upload ok') class download(BaseRequestHandler): def get(self): #id=self.request.get('id') o = MyModel.all().get() #self.response.out.write(''.join('%s: %s <br/>' % (a, getattr(o, a)) for a in dir(o))) self.response.out.write(o) application = webapp.WSGIApplication( [ ('/?', upload), ('/download',download), ], debug=True ) def main(): run_wsgi_app(application) if __name__ == "__main__": main() my index.html is : <form action="/" method="post"> <input type="file" name="file" /> <input type="submit" /> </form> and it show : <__main__.MyModel object at 0x02506830> but ,i don't want to see this , i want to download it , how to change my code to run, thanks updated it is ok now : class upload(BaseRequestHandler): def get(self): self.render_template('index.html',) def post(self): file=self.request.get('file') obj = MyModel() obj.blob = db.Blob(file) obj.put() self.response.out.write('upload ok') class download(BaseRequestHandler): def get(self): #id=self.request.get('id') o = MyModel.all().order('-').get() #self.response.out.write(''.join('%s: %s <br/>' % (a, getattr(o, a)) for a in dir(o))) self.response.headers['Content-Type'] = "image/png" self.response.out.write(o.blob) and new question is : if you upload a 'png' file ,it will show successful , but ,when i upload a rar file ,i will run error , so how to set Content-Type automatically , and what is the Content-Type of the 'rar' file thanks

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  • Do any languages other than haskell/agda have a hindley-milner type system and type classes?

    - by Jimmy Hoffa
    In pondering what gives Haskell such a layer of mental pain in becoming proficient the main thing I can think of are the Monads, Applicatives, Functors, and gaining an intuition to know how a list or maybe will behave in regards to sequence or alternate or bind etc. But why haven't other languages presented these same concepts given the usefulness of monads/applicatives/etc? It occurs to me, type classes are the key, so the question is: Have any languages other than Haskell/Agda actually implemented type classes in the same or similar way?

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  • Webpage loading with wrong content-type after setting up CloudFlare

    - by Daniel Little
    I recently migrated my blog to the Ghost service, I've also setup an alias DNS record with CloudFlare. While showing the blog to a colleague I discovered one of the posts wasn't loading properly and would instead prompt to be downloaded with an application/octet-stream content-type. I can view all the pages without any issues and I believe we're both on the same network as well. Has anyone received a wrong content type like application/octet-stream using CloudFlare, or know what I can do to correct this?

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  • Why doesn't Haskell have type-level lambda abstractions?

    - by Petr Pudlák
    Are there some theoretical reasons for that (like that the type checking or type inference would become undecidable), or practical reasons (too difficult to implement properly)? Currently, we can wrap things into newtype like newtype Pair a = Pair (a, a) and then have Pair :: * -> * but we cannot do something like ?(a:*). (a,a). (There are some languages that have them, for example, Scala does.)

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  • How refresh a DrawingArea in PyGTK ?

    - by Lialon
    I have an interface created with Glade. It contains a DrawingArea and buttons. I tried to create a Thread to refresh every X time my Canva. After a few seconds, I get error messages like: "X Window Server 0.0", "Fatal Error IO 11" Here is my code : import pygtk pygtk.require("2.0") import gtk import Canvas import threading as T import time import Map gtk.gdk.threads_init() class Interface(object): class ThreadCanvas(T.Thread): """Thread to display the map""" def __init__(self, interface): T.Thread.__init__(self) self.interface = interface self.started = True self.start() def run(self): while self.started: time.sleep(2) self.interface.on_canvas_expose_event() def stop(self): self.started = False def __init__(self): self.interface = gtk.Builder() self.interface.add_from_file("interface.glade") #Map self.map = Map.Map(2,2) #Canva self.canvas = Canvas.MyCanvas(self.interface.get_object("canvas"),self.game) self.interface.connect_signals(self) #Thread Canvas self.render = self.ThreadCanvas(self) def on_btnChange_clicked(self, widget): #Change map self.map.change() def on_interface_destroy(self, widget): self.render.stop() self.render.join() self.render._Thread__stop() gtk.main_quit() def on_canvas_expose_event(self): st = time.time() self.canvas.update(self.map) et = time.time() print "Canvas refresh in : %f times" %(et-st) def main(self): gtk.main() How can i fix these errors ?

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  • Webservice Return Generic Result Type or Purposed Result Type

    - by hanzolo
    I'm building a webservice which returns JSON / XML / SOAP at the moment.. and I'm not entirely sure which approach for returning results is best. Which would be a better return value? A generic "transfer" type structure, which carries Generic properties or a purposed type with distinct properties: class GenericTransferObject{ public string returnVal; public string returnType; } VS class PurposedTransferObject_1{ public string Property1; } //and then building additional "types" for additional values class PurposedTransferObject_2 { public string PropertyA; public string PropertyB; } Now, this would be the serialized and returned from a web service call via some client technology, JQuery in this example. SO if I called: /GetDaysInWeek/ I would either get back: {"returnType": "DaysInWeek", "returnVal": "365" } OR {"DaysInWeek": "365"} And then it would go from there. On the one hand there's flexibilty with the 1st example. I can add "returnTypes" without needing to adjust the client other than referencing an additional "index".. but if I had to add a property, now i'm changing a structure definition.. Is there an obvious choice in this situation?

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  • Refactoring a Single Rails Model with large methods & long join queries trying to do everything

    - by Kelseydh
    I have a working Ruby on Rails Model that I suspect is inefficient, hard to maintain, and full of unnecessary SQL join queries. I want to optimize and refactor this Model (Quiz.rb) to comply with Rails best practices, but I'm not sure how I should do it. The Rails app is a game that has Missions with many Stages. Users complete Stages by answering Questions that have correct or incorrect Answers. When a User tries to complete a stage by answering questions, the User gets a Quiz entry with many Attempts. Each Attempt records an Answer submitted for that Question within the Stage. A user completes a stage or mission by getting every Attempt correct, and their progress is tracked by adding a new entry to the UserMission & UserStage join tables. All of these features work, but unfortunately the Quiz.rb Model has been twisted to handle almost all of it exclusively. The callbacks began at 'Quiz.rb', and because I wasn't sure how to leave the Quiz Model during a multi-model update, I resorted to using Rails Console to have the @quiz instance variable via self.some_method do all the heavy lifting to retrieve every data value for the game's business logic; resulting in large extended join queries that "dance" all around the Database schema. The Quiz.rb Model that Smells: class Quiz < ActiveRecord::Base belongs_to :user has_many :attempts, dependent: :destroy before_save :check_answer before_save :update_user_mission_and_stage accepts_nested_attributes_for :attempts, :reject_if => lambda { |a| a[:answer_id].blank? }, :allow_destroy => true #Checks every answer within each quiz, adding +1 for each correct answer #within a stage quiz, and -1 for each incorrect answer def check_answer stage_score = 0 self.attempts.each do |attempt| if attempt.answer.correct? == true stage_score += 1 elsif attempt.answer.correct == false stage_score - 1 end end stage_score end def winner return true end def update_user_mission_and_stage ####### #Step 1: Checks if UserMission exists, finds or creates one. #if no UserMission for the current mission exists, creates a new UserMission if self.user_has_mission? == false @user_mission = UserMission.new(user_id: self.user.id, mission_id: self.current_stage.mission_id, available: true) @user_mission.save else @user_mission = self.find_user_mission end ####### #Step 2: Checks if current UserStage exists, stops if true to prevent duplicate entry if self.user_has_stage? @user_mission.save return true else ####### ##Step 3: if step 2 returns false: ##Initiates UserStage creation instructions #checks for winner (winner actions need to be defined) if they complete last stage of last mission for a given orientation if self.passed? && self.is_last_stage? && self.is_last_mission? create_user_stage_and_update_user_mission self.winner #NOTE: The rest are the same, but specify conditions that are available to add badges or other actions upon those conditions occurring: ##if user completes first stage of a mission elsif self.passed? && self.is_first_stage? && self.is_first_mission? create_user_stage_and_update_user_mission #creates user badge for finishing first stage of first mission self.user.add_badge(5) self.user.activity_logs.create(description: "granted first-stage badge", type_event: "badge", value: "first-stage") #If user completes last stage of a given mission, creates a new UserMission elsif self.passed? && self.is_last_stage? && self.is_first_mission? create_user_stage_and_update_user_mission #creates user badge for finishing first mission self.user.add_badge(6) self.user.activity_logs.create(description: "granted first-mission badge", type_event: "badge", value: "first-mission") elsif self.passed? create_user_stage_and_update_user_mission else self.passed? == false return true end end end #Creates a new UserStage record in the database for a successful Quiz question passing def create_user_stage_and_update_user_mission @nu_stage = @user_mission.user_stages.new(user_id: self.user.id, stage_id: self.current_stage.id) @nu_stage.save @user_mission.save self.user.add_points(50) end #Boolean that defines passing a stage as answering every question in that stage correct def passed? self.check_answer >= self.number_of_questions end #Returns the number of questions asked for that stage's quiz def number_of_questions self.attempts.first.answer.question.stage.questions.count end #Returns the current_stage for the Quiz, routing through 1st attempt in that Quiz def current_stage self.attempts.first.answer.question.stage end #Gives back the position of the stage relative to its mission. def stage_position self.attempts.first.answer.question.stage.position end #will find the user_mission for the current user and stage if it exists def find_user_mission self.user.user_missions.find_by_mission_id(self.current_stage.mission_id) end #Returns true if quiz was for the last stage within that mission #helpful for triggering actions related to a user completing a mission def is_last_stage? self.stage_position == self.current_stage.mission.stages.last.position end #Returns true if quiz was for the first stage within that mission #helpful for triggering actions related to a user completing a mission def is_first_stage? self.stage_position == self.current_stage.mission.stages_ordered.first.position end #Returns true if current user has a UserMission for the current stage def user_has_mission? self.user.missions.ids.include?(self.current_stage.mission.id) end #Returns true if current user has a UserStage for the current stage def user_has_stage? self.user.stages.include?(self.current_stage) end #Returns true if current user is on the last mission based on position within a given orientation def is_first_mission? self.user.missions.first.orientation.missions.by_position.first.position == self.current_stage.mission.position end #Returns true if current user is on the first stage & mission of a given orientation def is_last_mission? self.user.missions.first.orientation.missions.by_position.last.position == self.current_stage.mission.position end end My Question Currently my Rails server takes roughly 500ms to 1 sec to process single @quiz.save action. I am confident that the slowness here is due to sloppy code, not bad Database ERD design. What does a better solution look like? And specifically: Should I use join queries to retrieve values like I did here, or is it better to instantiate new objects within the model instead? Or am I missing a better solution? How should update_user_mission_and_stage be refactored to follow best practices? Relevant Code for Reference: quizzes_controller.rb w/ Controller Route Initiating Callback: class QuizzesController < ApplicationController before_action :find_stage_and_mission before_action :find_orientation before_action :find_question def show end def create @user = current_user @quiz = current_user.quizzes.new(quiz_params) if @quiz.save if @quiz.passed? if @mission.next_mission.nil? && @stage.next_stage.nil? redirect_to root_path, notice: "Congratulations, you have finished the last mission!" elsif @stage.next_stage.nil? redirect_to [@mission.next_mission, @mission.first_stage], notice: "Correct! Time for Mission #{@mission.next_mission.position}", info: "Starting next mission" else redirect_to [@mission, @stage.next_stage], notice: "Answer Correct! You passed the stage!" end else redirect_to [@mission, @stage], alert: "You didn't get every question right, please try again." end else redirect_to [@mission, @stage], alert: "Sorry. We were unable to save your answer. Please contact the admministrator." end @questions = @stage.questions.all end private def find_stage_and_mission @stage = Stage.find(params[:stage_id]) @mission = @stage.mission end def find_question @question = @stage.questions.find_by_id params[:id] end def quiz_params params.require(:quiz).permit(:user_id, :attempt_id, {attempts_attributes: [:id, :quiz_id, :answer_id]}) end def find_orientation @orientation = @mission.orientation @missions = @orientation.missions.by_position end end Overview of Relevant ERD Database Relationships: Mission - Stage - Question - Answer - Attempt <- Quiz <- User Mission - UserMission <- User Stage - UserStage <- User Other Models: Mission.rb class Mission < ActiveRecord::Base belongs_to :orientation has_many :stages has_many :user_missions, dependent: :destroy has_many :users, through: :user_missions #SCOPES scope :by_position, -> {order(position: :asc)} def stages_ordered stages.order(:position) end def next_mission self.orientation.missions.find_by_position(self.position.next) end def first_stage next_mission.stages_ordered.first end end Stage.rb: class Stage < ActiveRecord::Base belongs_to :mission has_many :questions, dependent: :destroy has_many :user_stages, dependent: :destroy has_many :users, through: :user_stages accepts_nested_attributes_for :questions, reject_if: :all_blank, allow_destroy: true def next_stage self.mission.stages.find_by_position(self.position.next) end end Question.rb class Question < ActiveRecord::Base belongs_to :stage has_many :answers, dependent: :destroy accepts_nested_attributes_for :answers, :reject_if => lambda { |a| a[:body].blank? }, :allow_destroy => true end Answer.rb: class Answer < ActiveRecord::Base belongs_to :question has_many :attempts, dependent: :destroy end Attempt.rb: class Attempt < ActiveRecord::Base belongs_to :answer belongs_to :quiz end User.rb: class User < ActiveRecord::Base belongs_to :school has_many :activity_logs has_many :user_missions, dependent: :destroy has_many :missions, through: :user_missions has_many :user_stages, dependent: :destroy has_many :stages, through: :user_stages has_many :orientations, through: :school has_many :quizzes, dependent: :destroy has_many :attempts, through: :quizzes def latest_stage_position self.user_missions.last.user_stages.last.stage.position end end UserMission.rb class UserMission < ActiveRecord::Base belongs_to :user belongs_to :mission has_many :user_stages, dependent: :destroy end UserStage.rb class UserStage < ActiveRecord::Base belongs_to :user belongs_to :stage belongs_to :user_mission end

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  • Apache serving wrong Content-Type for Rails files

    - by NudeCanalTroll
    Apache keeps serving up my Rails files with a Content-Type of 'text/plain' in the header. I have mod_mime installed, a mime.types files with all the correct MIME assignments, and the following code in my configuration. Any thoughts? DefaultType text/plain <IfModule mime_module> TypesConfig /etc/apache2/mime.types AddType application/x-compress .Z AddType application/x-gzip .gz .tgz </IfModule>

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  • how to create an object using self?

    - by Nick
    I thought I understood the use of self while referring to anything in the current class. After encountering this warning and subsequent run failure, I have googled many variants of "define self" or "usage of self" and gotten nowhere. This problem is how to create an object without the warning, and understand why. #import <Cocoa/Cocoa.h> @interface Foo : NSObject { Foo *obj; } -(void)beta; @end #import "Foo.h" @implementation Foo -(void)beta{ obj = [self new]; // 'Foo' may not respond to '-new' } @end Note, if I substitute Foo for self, there's no problem. I thought the class name and self were equivalent, but obviously the compiler doesn't think so. Perhaps an explanation of what's wrong here will not only solve my problem but also enlighten my understanding of the usage of self. Are there any tutorials about proper usage of self? I couldn't find anything beyond something like "self is the receiver of the message," which I didn't help me at all.

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  • Jack of all trades, master of none [closed]

    - by Rope
    I've got a question similar to this one: Is looking for code examples constantly a sign of a bad developer? though not entirely. I got off college 2 years ago and I'm currently struggling with a University study. Most likely I'll have to drop out and start working within the next couple of months. Now here's the pickle. I have no speciality what so ever. When I got out of college I had worked with C, C++ and Java. I had had an internship at NEC-Philips and got familiar with C# (.NET) and I taught myself how it worked. After college I started working with PHP, HTML,SQL, MySQL Javascript and Jquery. I'm currently teaching myself Ruby on Rails and thus Ruby. At my university I also got familiar with MATLAB. As you can see I've got a broad scope of languages and frameworks I'm familiar with, but none I know inside-out. So I guess this kinda applies to me: "Jack of all trades, master of none.". I've been looking for jobs and I've noticed that most of them require some years of experience with a certain language and some specifications that apply to that language. My question is: How do I pick a speciality? And how do I know if I'll actually enjoy it? As I've worked with loads of languages how would I be able to tell this is right for me? I don't like being tied down to a specific role and I quite like being a generalist. But in order to make more money I would need a specialisation. How would I pick something that goes against my nature? Thanks in advance, Rope.

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  • How to learn programming for a medium scale project form a beginner? [closed]

    - by Lin Xiangyu
    I study programming by myself.I have learn servel programming languages. but I never write a project more than 1000 lines. I know the best way to improve programming skills is practise. The problem is many books, just talk about the programming language, or talk about build a project from a high level. Fews of books will teach how to build a middle scale project. For example, I want to build a simple HTTP Server(Nor like Apache or just a simple listenr to a port), a Markdown Parser, or a download tools just like emule or wget. I don't know what to do. I may found peaces of code in the web, or found familiar project in the Github. I don't know how to read the code. I want to some tutorial that can told me how to build the project step by step, teacher me how to write thousands lines of code. Any suggest?

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  • Audiobooks for programmers?

    - by Zoot
    I'm a programmer with a two-hour round trip commute to work each day. I'd like to fill some of that time with audiobooks about software development. Any audiobooks that would help me become a better programmer would be appreciated. I'm thinking that books about design patterns and non-fiction about computing history might be good here, but I'm open to anything. Keeping in mind that I will be listening to this in a car, what are the best audiobooks that I can listen to? EDIT: Many people have also suggested podcasts. This is appreciated, but since podcasts arrive in a constantly arriving stream of data rather than as a finite amount of data, ways to juggle all of these different content streams would also be appreciated. To be more specific to my situation, my commuting vehicle has an MP3 CD player, USB input for MP3 files, and AUX input. I own Android and webOS devices that can be plugged into the AUX input.

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  • Learning and Developing with PHP [closed]

    - by KyelJmD
    I am here to ask you What is a good PHP Book that doesn't contain too much details but it is compose of all necessary information to develop in PHP such as (OO PHP, Handling Forms, Database etc etc) This may be subjective but I've tried to look php book recomendations here at Stackoverflow but I cannot find any. Next is What are the things I need to know in learning a PHp framework? specifically I want to learn CAKEPHP. NOTE I do not need those lenghty books that discuss loops and such I already have experience programming with java and C#.

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  • Is conditional return type ever a good idea?

    - by qegal
    So I have a method that's something like this: -(BOOL)isSingleValueRecord And another method like this: -(Type)typeOfSingleValueRecord And it occurred to me that I could combine them into something like this: -(id)isSingleValueRecord And have the implementation be something like this: -(id)isSingleValueRecord { //If it is single value if(self.recordValue = 0) { //Do some stuff to determine type, then return it return typeOfSingleValueRecord; } //If its not single value else { //Return "NO" return [NSNumber numberWithBool:NO]; } } So combining the two methods makes it more efficient but makes the readability go down. In my gut, I feel like I should go with the two-method version, but is that really right? Is there any case that I should go with the combined version?

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  • Could someone break this nasty habit of mine please?

    - by MimiEAM
    I recently graduated in cs and was mostly unsatisfied since I realized that I received only a basic theoretical approach in a wide range of subjects (which is what college is supposed to do but still...) . Anyway I took the habit of spending a lot of time looking for implementations of concepts and upon finding those I will used them as guides to writing my own implementation of those concepts just for fun. But now I feel like the only way I can fully understand a new concept is by trying to implement from scratch no matter how unoptimized the result may be. Anyway this behavior lead me to choose by default the hard way, that is time consuming instead of using a nicely written library until I hit my head again a huge wall and then try to find a library that works for my purpose.... Does anyone else do that and why? It seems so weird why would anyone (including me) do that ? Is it a bad practice ? and if so how can i stop doing that ?

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  • Opinion for my recruitment portal idea [closed]

    - by user1498503
    I am creating a recruitment portal for IT professionals. In this, recruiters while creating a job post would be asked to create a skills requirement matrix. Essential Skills : asp.net MVC Entity Framework Desired Skills : SQL Server 2008 IIS 7.0 On the other hand job seekers would also have their own skills matrix Jobseeker #1 Core Skills : asp.net MVC Entity Framework MangoDB Secondary Skills : SQL Server 2008 IIS 7.0 Jobseeker #2 Core Skills : asp.net Web forms Secondary Skills : SQL Server 2008 IIS 7.0 So when both job seekers apply for the same job. Would it be a good idea for both of them to see each other's skills matrix for comparison?Also no personal details and CVs are shared. I think comparisons would help job seekers to understand what their areas of improvement are and could motivate to fill the skills gap. Your opinion would be appreciated. Regards

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  • Topics for covering in-depth programming knowledge

    - by black_belt
    I pursued my bachelors' degree in business administration, but my interest in Information Technology led me to acquire some knowledge of PHP programming and MySQL database. I find programming so interesting that I haven't applied for any job since my graduation. Currently I am staying home and just trying to acquire in-depth knowledge of PHP programming. So far I have developed couple of websites and web applications including Inventory+ Point of Sale Software and an Accounting system for small organizations. I aim to have knowledge that a Computer Science graduate should have, and for that I want to read books but I have no idea where to start from. Could you please suggest me some books and topics that I should study on? Thanks a lot :)

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  • What should a programmer's yearly routine be to maximize their technical skills?

    - by sguptaet
    2 years ago I made a big career change into programming. I learned various technologies on my own without any prior experience. I really love it and feel lucky with all the resources around us to help us learn. Books, courses, open-source, etc. There are so many avenues. I'm wondering what a good routine would be to follow to maximize my software development skills. I don't believe just building software is the way, because that leaves no time for learning new concepts or technologies. I'm looking for an answer like this: Take a new concept sabbatical/workshop 2 weeks per year. Read 1 theoretical and 1 practical programming book per year. Learn 1 additional language every 2 years. Take a 1 week vacation every 6 months. Etc. I realize that the above might sound naive and unrealistic as there are so many factors. But I'd like to know the "recipe" that you think is best that will serve as a guide for people.

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  • At what point does programming become a useful skill?

    - by Elip
    This is probably a very difficult question to answer, because of its subjectivity, but even a vague guess would help me out: Now that Khan Academy is beginning to offer Computer Science lectures I'm getting an itch to learn programming again. I maybe am a bit more technical than your average computer user, using Ubuntu as my OS, LaTeX for writing and I know some small tricks like regular expressions or boolean search for google. However from my previous attempts to learn programming, I realized I do not have a natural aptitude for it and I also don't seem to enjoy the process. But I am fairly certain that a basic proficiency in programming could prove to be very beneficial for me career wise; I also often get ideas for little scripts that I cannot implement. My question is: Let's say you study programming 1 hour / day on average. At what point will you become good enough so that programming can be used for automating tasks and actually saving time? Do you think programming is worth picking up if you never have the ambition to make it your career or even your hobby, but use it strictly for utility purposes?

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  • Progressing past CRUD applications in PHP?

    - by Anonymous -
    I've been programming in PHP for about a year and am at the following stage: Have a good 'feel' for the language Can create CRUD applications competently Can utilize an MVC structure to allow for future expansion of code Using the points listed above, I've created a number of my own applications for practise - including but not limited to; a forum, social network etc. My question may be a little vague but should hopefully be answerable. I feel as though there isn't anything else I would need to know about PHP to allow me to create websites, though I'm sure I'm wrong. What advanced/complex PHP topics could I look at that have a real-world use and will allow me to enhance both my skill as a programmer and applications in general? Recently I've looked a lot more at javascript/jQuery allowing me to give my applications a richer user interface which has been a great learning experience and proving very useful.

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  • Recommended learning path?

    - by stairmast0r
    First, my current standing: I know C++ at an.. advanced beginner level? I've gone through a book, I know the syntax well enough, I know a fair amount of standard library functions, and I've programmed some simple console stuff with it. I'd probably be able to program more with it if I knew how to structure a program, but I just can't seem to wrap my head around the whole concept of structuring something remotely complex. I've messed around with Java for a day or two, and the syntax was extremely easy to get the hang of, except that I didn't really know any functions. I'm plenty willing to learn, and to work hard to do so, but I don't really know where to go from here. Now, at the risk of sounding cliche, what I'd like to become is someone like the great three of id; Carmack, Romero, and Abrash. To be considered a genius. I believe anything can be learned, and nothing mentally limits anyone except lack of desire to learn. But I don't know how to learn this. They learned by doing, and making do with what resources they had. On the other hand, I have access to almost any books I want, access to the internet, and access to a more than capable computer and software. Should I learn more languages? Assembly? LISP? BASIC? Haskell? Should I dive straight into advanced topics like OpenGL? Or should I wait until I feel I've come closer to mastering the simpler things, like console programs, first? Should I follow tutorials? Should I follow books? Should I just dive into writing something and follow a reference manual as I go? What order should I do all this in? How should I do it? I want to completely master this; to be considered a genius. The most perfect career I can imagine is to start the next id. I have the drive to do it, I just don't know where to begin...

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  • How to learn programming from very basic level to advanced level? [closed]

    - by user1022209
    I know many programming languages ,skills and concepts in very basic, such as PHP, Java, Object-oriented technology. Using PHP, I can build a simple website with CRUD, login function. Using Java, I can make an basic swing csv/plain text editor in which user can switch between 2 different views. In term of object-oriented Technology, I clearly understand what encapsulation, inheritance and Polymorphism are I want to know more about programming. Sometimes I "google" some of the topics I am interested at , the more I see on the internet, the more I feel I am a small potato in the world ( indeed I am ). The codings/concepts are difficult to understand. I lacks confidence right now so I am asking this question :( What is the best way to learn programming to advanced level? Just buy a book and read it page to page? Thanks for any helps

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  • .NET Type Conversion Issue: Simple but difficult

    - by jaderanderson
    Well, the question is kinda simple. I have a object defined as: public class FullListObject : System.Collections.ArrayList, IPagedCollection And when i try to: IPagedCollection pagedCollection = (IPagedCollection)value; It don't work... value is a FullListObject... this is my new code trying to get around a issue with the "is" operator. When the system tests (value is IPagedCollection) it never gets true for FullListObject. How to cast the object to another object with a interface type?

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  • Dynamically creating a Generic Type at Runtime

    - by Rick Strahl
    I learned something new today. Not uncommon, but it's a core .NET runtime feature I simply did not know although I know I've run into this issue a few times and worked around it in other ways. Today there was no working around it and a few folks on Twitter pointed me in the right direction. The question I ran into is: How do I create a type instance of a generic type when I have dynamically acquired the type at runtime? Yup it's not something that you do everyday, but when you're writing code that parses objects dynamically at runtime it comes up from time to time. In my case it's in the bowels of a custom JSON parser. After some thought triggered by a comment today I realized it would be fairly easy to implement two-way Dictionary parsing for most concrete dictionary types. I could use a custom Dictionary serialization format that serializes as an array of key/value objects. Basically I can use a custom type (that matches the JSON signature) to hold my parsed dictionary data and then add it to the actual dictionary when parsing is complete. Generic Types at Runtime One issue that came up in the process was how to figure out what type the Dictionary<K,V> generic parameters take. Reflection actually makes it fairly easy to figure out generic types at runtime with code like this: if (arrayType.GetInterface("IDictionary") != null) { if (arrayType.IsGenericType) { var keyType = arrayType.GetGenericArguments()[0]; var valueType = arrayType.GetGenericArguments()[1]; … } } The GetArrayType method gets passed a type instance that is the array or array-like object that is rendered in JSON as an array (which includes IList, IDictionary, IDataReader and a few others). In my case the type passed would be something like Dictionary<string, CustomerEntity>. So I know what the parent container class type is. Based on the the container type using it's then possible to use GetGenericTypeArguments() to retrieve all the generic types in sequential order of definition (ie. string, CustomerEntity). That's the easy part. Creating a Generic Type and Providing Generic Parameters at RunTime The next problem is how do I get a concrete type instance for the generic type? I know what the type name and I have a type instance is but it's generic, so how do I get a type reference to keyvaluepair<K,V> that is specific to the keyType and valueType above? Here are a couple of things that come to mind but that don't work (and yes I tried that unsuccessfully first): Type elementType = typeof(keyvalue<keyType, valueType>); Type elementType = typeof(keyvalue<typeof(keyType), typeof(valueType)>); The problem is that this explicit syntax expects a type literal not some dynamic runtime value, so both of the above won't even compile. I turns out the way to create a generic type at runtime is using a fancy bit of syntax that until today I was completely unaware of: Type elementType = typeof(keyvalue<,>).MakeGenericType(keyType, valueType); The key is the type(keyvalue<,>) bit which looks weird at best. It works however and produces a non-generic type reference. You can see the difference between the full generic type and the non-typed (?) generic type in the debugger: The nonGenericType doesn't show any type specialization, while the elementType type shows the string, CustomerEntity (truncated above) in the type name. Once the full type reference exists (elementType) it's then easy to create an instance. In my case the parser parses through the JSON and when it completes parsing the value/object it creates a new keyvalue<T,V> instance. Now that I know the element type that's pretty trivial with: // Objects start out null until we find the opening tag resultObject = Activator.CreateInstance(elementType); Here the result object is picked up by the JSON array parser which creates an instance of the child object (keyvalue<K,V>) and then parses and assigns values from the JSON document using the types  key/value property signature. Internally the parser then takes each individually parsed item and adds it to a list of  List<keyvalue<K,V>> items. Parsing through a Generic type when you only have Runtime Type Information When parsing of the JSON array is done, the List needs to be turned into a defacto Dictionary<K,V>. This should be easy since I know that I'm dealing with an IDictionary, and I know the generic types for the key and value. The problem is again though that this needs to happen at runtime which would mean using several Convert.ChangeType() calls in the code to dynamically cast at runtime. Yuk. In the end I decided the easier and probably only slightly slower way to do this is a to use the dynamic type to collect the items and assign them to avoid all the dynamic casting madness: else if (IsIDictionary) { IDictionary dict = Activator.CreateInstance(arrayType) as IDictionary; foreach (dynamic item in items) { dict.Add(item.key, item.value); } return dict; } This code creates an instance of the generic dictionary type first, then loops through all of my custom keyvalue<K,V> items and assigns them to the actual dictionary. By using Dynamic here I can side step all the explicit type conversions that would be required in the three highlighted areas (not to mention that this nested method doesn't have access to the dictionary item generic types here). Static <- -> Dynamic Dynamic casting in a static language like C# is a bitch to say the least. This is one of the few times when I've cursed static typing and the arcane syntax that's required to coax types into the right format. It works but it's pretty nasty code. If it weren't for dynamic that last bit of code would have been a pretty ugly as well with a bunch of Convert.ChangeType() calls to litter the code. Fortunately this type of type convulsion is rather rare and reserved for system level code. It's not every day that you create a string to object parser after all :-)© Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  CSharp   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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