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• NoSQL and meteorological data

  - by christian studer

  So there's this new cool thing, these NoSQL-databases. And so there's my data: Rows of rows of rows of meteorological data: Values, representing certain measurements at a certain station (Identified by a WMO number, not coordinates), at a certain time. Not every station measures every parameter, not every parameter is measured all the time. I store this data (30 years worth of hourly values, resulting in ~1 billion values) currently in MySQL. The continous growth and the forseeable addition of even more data give me a little headache. Reading about the document based NoSQL systems which seem to scale rather easily, I was wondering if NoSQL is a viable data storage concept for meteorological data too. Do you have any experience with this?

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• Can I use the newer versions of Visual Studio to do "old" things?

  - by Ptah- Opener of the Mouth

  I have several ATL/COM-based DLLs that I've been using Visual C++ 6.0 on. I require a couple of "old" things out of the generated DLLs: (1) They must be compatible with projects developed in Visual Basic 6.0 (the old VB6, emphatically not VB.Net). (2) They must be compatible with old operating systems - minimum Windows 98 SE. To be clear, I mean they must run on such OSes, not that I would have to be able to develop them on a machine running such an OS. I am sick of Visual Studio 6.0. Converting to Dot Net (or any other major change like that) is out of the question at the current time, so I must continue to use VB6. But can I switch to the newer Visual Studio's C++, with a minimum of effort (i.e. little if any required recoding)? If so, are there any "gotchas" I should watch out for? Thanks.

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• What should be done first: Code reviews or Unit tests?

  - by goldenmean

  Hello, If a developer implements code for some module and wants to get it reviewed. What should be the order : *First unit test the module after designing test cases for the module, debugging and fixing the bugs and then give the modified code for peer code review (Pros- Code to be reviewed is 'clean' to a good extent. Reduces some avoidable review comments and rework. Cons- Developer might spend large time debugging/fixing a bug which could have pointed/anticipated in peer code reviews) Or *First do the code review with peers and then go for unit testing. What are your thoughts/experience on this? I believe this approach for unit testing, code reviewing should be programming language agnostic, but it would be interesting to know otherwise(if applicable) with specific examples. -AD

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• iphone using 2 tableview

  - by Anonymous

  Hi, I 'm a iphone programming newbie. I m trying to implement an app with multi-level tableviews. The idea is if someone selects something on the first screen say then a new view opens(tableview) car make> list of models Honda > Acura, S2000,accord ... My challenge is to show the list of models in a new tableview & secondly change the size of hte list depending on the car selected. I have programmed so that when i select 'Honda' a new tableview opens. How do i populate data for the second table?? Any suggestions on how to proceed? thanks

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• Localized tables and Entity Framework

  - by Pyttroll

  Hi all, I have a scenario where I need to localized values of objects in my database. Let's say you have an application that can create animals, if the user is english the value of the "Name" property of an animal would be entered as "Cat" in the UI whereas it would be entered as "Chat" in french. The animal culture table would contain 2 records pointing to the same animal in the parent table. When reading values back, if the value of "Name" does not exist in the user culture the default value (value the object was originally created with) would be used. The following diagrams demonstrate how the data is stored in SQL: I'm trying to map this schema to an object model using the Entity Framework, I'm a bit confused as to what the best way to approach the problem. Is EF appropriate for this? Should I used EF4? This EF model will be used by .NET RIA Services. Thanks, Pierre-Yves Troel Ayuda Media Systems http://www.ayudasystems.com

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• Encrypt text using a number

  - by Adam Matan

  Project Euler I have recently begun to solve some of the Project Euler riddles. I found the discussion forum in the site a bit frustrating (most of the discussions are closed and poorly-threaded), So I have decided to publish my Python solutions on launchpad for discussion. The problem is that it seems quite unethical to publish these solutions, as it would let other people gain reputation without doing the programming work, which the site deeply discourages. My Encryption problem I want to encrypt my answers so that only those who have already solved the riddles can see my code. The logical key would be the answer to the riddle, which is always numeric. In order to prevent brute-force attacks on my answers, I want to find an encryption algorithm that takes a significantly long time (few seconds) to run. Do you know any such algorithm? I would fancy a Python package, which I can attach to the code, over an external program that might have portability issues. Thanks, Adam

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• Editting ForeignKey from "child" table

  - by profuel

  I'm programming on py with django. I have models: class Product(mymodels.Base): title = models.CharField() price = models.ForeignKey(Price) promoPrice = models.ForeignKey(Price, related_name="promo_price") class Price(mymodels.Base): value = models.DecimalField(max_digits=10, decimal_places=3) taxValue = models.DecimalField("Tax Value", max_digits=10, decimal_places=3) valueWithTax = models.DecimalField("Value with Tax", max_digits=10, decimal_places=3) I want to see INPUTs for both prices when editing product, but cannot find any possibility to do that. inlines = [...] works only from Price to Product, which is stupid in this case. Thanx for adnvance.

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• How to use NSTableView's selectedRowIndexes?

  - by Jakub Lédl

  Hi guys, I'm just learning some basic programming in Objective C and Cocoa. I'm trying to get some data from NSTableView. Based on what I read in one tutorial, I wrote this: NSArray * items = [[itemsTableView selectedRowEnumerator] allObjects]; But then I learned that selectedRowEnumerator was deprecated already in 10.3 Panther and that I should use selectedRowIndexes. The problem is, I didn't find how to actually use the returned NSIndexSet to achieve the same result as with code written above. So, If anyone could give me a tip, I would be very grateful. Thanks.

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• What makes COBOL such a hated language?

  - by cable

  I'm rather young and so I haven't experienced the times when COBOL was still in use and even going mainstream, maybe you can help me out. Everywhere I go and surf I: Am getting told about how horrible COBOL is See sites making fun of COBOL Hear that I should be happy that I don't have to use COBOL, from older programmers See others make anti-COBOL-ist jokes I don't know much about COBOL, except that it is still used everywhere as many old systems haven't got refactored and that it is even still developed and managed. I have also looked at some COBOL code examples but it seems like they are as rare and expensive as unicorn blood. If you close this question or give me sarcastic, irrelevant answers I'll have to learn COBOL to find it out the hard way. I'm serious.

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• Pros and Cons of Java HTML to XML cleaners

  - by cjavapro

  I am looking to allow HTML emails (and other HTML uploads) without letting in scripts and stuff. I plan to have a white list of safe tags and attributes as well as a whitelist of CSS tags and value regexes (to prevent automatic return receipt). I asked a question: Parse a badly formatted XML document (like an HTML file) I found there are many many ways to do this. Some systems have built in sanitizers (which I don't care so much about). I will post some answers and say Community Wiki. Please post any other options you like and say Community Wiki so they can be voted on. Also any comments or wiki edits on what part of a certain product is better and what is not would be greatly appreciated. This page is a very nice listing page but I get kinda lost http://java-source.net/open-source/html-parsers

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• how to create a particle system on iphone and retain the created particles?

  - by lukya

  Hi all, I need to create a particle system and retain the created particles. I need to shake / move the created particles with the iphone accelerometer. Also, the number of particles needs to be very high (I need to show sand!). I do not have any OpenGLES programming experience. After initial search, I found Cocos2D can be used for particle generation. But there is no way of retaining the particles in the CCParticle system. As a work around, I tried creating many sprites at the end of particle generation and shown them as particles. But moving few number of sprites with accelerometer drops the frame rate considerably. Please suggest how this can be achieved and whether I should look for some other framework or if some kind of similar demo code is available. Thanks, Swapnil

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• Importing ctype; embedding python in C++ application

  - by Drew

  I'm trying to embed python within a C++ based programming language (CCL: The compuatational control language, not that any of you have heard of it). Thus, I don't really have a "main" function to make calls from. I have made a test .cc program with a main, and when I compile it and run it, I am able to import my own python modules and system modules for use. When I embed my code in my CCL-based program and compile it (with g++), it seems I have most functionality, but I get the import error: ImportError: /usr/lib/python2.6/lib-dynload/_ctypes.so: undefined symbol: PyType_GenericNew Can someone explain this to me and how to go about solving it? It seems like I've linked the objects correctly. Thanks.

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• How can I integrate graphs and JPEG images with RAVE Reports?

  - by JonDave of the Philippines

  I really love RAVE Reports in creating multiple reports especially with formulas and accounting systems... but recently I am having problems with integrating JPEG Pictures and Graphs with my newly Delphi Language developed Little ERP System. I bought some JPEG Components but it seems problematic. I also experienced some irregularities with my RAVE Reports now. When I run my program then try to preview some reports, it seems to be running fine, but when I close the program, the EXE file is still in the taskbar. I need to ctrl-alt-delete first for me to use Report Previews normally. If I don't, RAVE REPORT ERROR message will appear everytime I click the PRINT button; it says "STREAM READ ERROR" even though I used to "FreeAndNil" to free the memory stream when Report Preview Form closes. When I tried to run the My Applications without previewing RAVE reports, the program closes perfectly. Any suggestions and recommendations will be an enormous help. Thank you.

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• Algorithm for Source Control System?

  - by Michael Stum

  I need to write a simple source control system and wonder what algorithm I would use for file differences? I don't want to look into existing source code due to license concerns. I need to have it licensed under MPL so I can't look at any of the existing systems like CVS or Mercurial as they are all GPL licensed. Just to give some background, I just need some really simple functions - binary files in a folder. no subfolders and every file behaves like it's own repository. No Metadata except for some permissions. Overall really simple stuff, my single concern really is how to store only the differences of a file from revision to revision without wasting too much space but also without being too inefficient (Maybe store a full version every X changes, a bit like Keyframes in Videos?)

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• Function Object in Java .

  - by Tony

  I wanna implement a javascript like method in java , is this possible ? Say , I have a Person class : public class Person { private String name ; private int age ; // constructor ,accessors are omitted } And a list with Person objects: Person p1 = new Person("Jenny",20); Person p2 = new Person("Kate",22); List<Person> pList = Arrays.asList(new Person[] {p1,p2}); I wanna implement a method like this: modList(pList,new Operation (Person p) { incrementAge(Person p) { p.setAge(p.getAge() + 1)}; }); modList receives two params , one is a list , the other is the "Function object", it loops the list ,and apply this function to every element in the list. In functional programming language,this is easy , I don't know how java do this? Maybe could be done through dynamic proxy, does that have a performance trade off?

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• How to write a shell in Python

  - by panzi

  I've written a small console application that can perform certain tasks. The user interface is similar to things like version control systems or yum etc. So basically you can think of it as a domain specific language. Now I'd like to write a (bash like) shell that can execute and auto-complete this language and has a command history (so I do not have to load and save the quite large xml files on each command). In a nutshell I want something like ipython but not for executing python code but my own DSL. Are there any libraries that help me doing this? I see that there is a readline and rlcompleter module in python but its documentation seems to indicate that this is only for use with the python shell itself, or did I miss something there?

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• Give me a practical use-case of Multi-set

  - by Calm Storm

  I would like to know a few practical use-cases (if they are not related/tied to any programming language it will be better).I can associate Sets, Lists and Maps to practical use cases. For example if you wanted a glossary of a book where terms that you want are listed alphabetically and a location/page number is the value, you would use the collection TreeMap(OrderedMap which is a Map) Somehow, I can't associate MultiSets with any "practical" usecase. Does someone know of any uses? http://en.wikipedia.org/wiki/Multiset does not tell me enough :) PS: If you guys think this should be community-wiki'ed it is okay. The only reason I did not do it was "There is a clear objective way to answer this question".

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• Why the "mutable default argument fix" syntax is so ugly, asks python newbie

  - by Cawas

  Now following my series of "python newbie questions" and based on another question. Go to http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#other-languages-have-variables and scroll down to "Default Parameter Values". There you can find the following: def bad_append(new_item, a_list=[]): a_list.append(new_item) return a_list def good_append(new_item, a_list=None): if a_list is None: a_list = [] a_list.append(new_item) return a_list So, question here is: why is the "good" syntax over a known issue ugly like that in a programming language that promotes "elegant syntax" and "easy-to-use"? Why not just something in the definition itself, that the "argument" name is attached to a "localized" mutable object like: def better_append(new_item, a_list=[].local): a_list.append(new_item) return a_list I'm sure there would be a better way to do this syntax, but I'm also almost positive there's a good reason to why it hasn't been done. So, anyone happens to know why?

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• kill -9 and production application

  - by valodzka

  Which problem can cause kill -9 in production application (in linux to be exact)? I have application which do some periodical work, stopping these takes long time, and I don't care if some jobs will be aborted - work can be finished by new processes. So can I use kill -9 just to stop it immediately or this can cause serious OS problems? For example, Unicorn, uses it as normal working procedure: When your application goes awry, a BOFH can just "kill -9" the runaway worker process without worrying about tearing all clients down, just one. But this article claims: The -9 (or KILL) argument to kill(1) should never be used on Unix systems

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• List available languages for PyGTK UI strings

  - by detly

  I'm cleaning up some localisation and translation settings in our PyGTK application. The app is only intended to be used under GNU/Linux systems. One of the features we want is for users to select the language used for the applications (some prefer their native language, some prefer English for consistency, some like French because it sounds romantic, etc). For this to work, I need to actually show a combo box with the various languages available. How can I get this list? In fact, I need a list of pairs of the language code ("en", "ru", etc) and the language name in the native language ("English (US)", "???????"). If I had to implement a brute force method, I'd do something like: look in the system locale dir (eg. "/usr/share/locale") for all language code dirs (eg. "en/") containing the relative path "LC_MESSAGES/OurAppName.mo". Is there a more programmatic way?

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• Button Application- iPhone Application

  - by Extremely frustrated

  I am a meganoob in iPhone Application programming. All I want to do is make an application with a single button. When you press the button, it plays an audio file. The button is just two images, one for the normal state and one for the pressed state. I have no clue how to get from point A to point B, it seems so straightforward in web design, why can't it be like that for this too? Anyone out there willing to drop some hints?

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• Why can't I install psycopg2? (Python 2.6.4, PostgreSQL 8.4, OS X 10.6)

  - by cojadate

  After running python setup.py install I get the following: Warning: Unable to find 'pg_config' filebuilding 'psycopg2._psycopg' extension gcc-4.0 -arch ppc -arch i386 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -O3 - DPSYCOPG_DEFAULT_PYDATETIME=1 -DPSYCOPG_VERSION="2.2.1 (dt dec ext pq3)" -DPSYCOPG_EXTENSIONS=1 -DPSYCOPG_NEW_BOOLEAN=1 -DHAVE_PQFREEMEM=1 -DHAVE_PQPROTOCOL3=1 -I/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -I. -c psycopg/psycopgmodule.c -o build/temp.macosx-10.3-fat-2.6/psycopg/psycopgmodule.o unable to execute gcc-4.0: No such file or directory error: command 'gcc-4.0' failed with exit status 1 There's probably something screamingly obvious there to anyone who knows the first thing about back-end web programming, but unfortunately it's all gobbledegook to me. The psycopg2 documentation was not helpful.

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• How do I draw an ellipse with arbitrary orientation pixel by pixel?

  - by amc

  Hi, I have to draw an ellipse of arbitrary size and orientation pixel by pixel. It seems pretty easy to draw an ellipse whose major and minor axes align with the x and y axes, but rotating the ellipse by an arbitrary angle seems trickier. Initially I though it might work to draw the unrotated ellipse and apply a rotation matrix to each point, but it seems as though that could cause errors do to rounding, and I need rather high precision. Is my suspicion about this method correct? How could I accomplish this task more precisely? I'm programming in C++ (although that shouldn't really matter since this is a more algorithm-oriented question).

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• strategies for learning complex software packages

  - by Tom

  I am a fairly novice Java programmer and I am currently working on a project to extend a piece of software that has been developed over a few years. So it has pretty big code base and the previous developers knew it well, so extending it is not going to be easy without a thorough understanding of the structure and function. 1) I had begun by trying to tackle small parts of the system and document them with mindmap. (particularly I am trying to document the interactions with external systems) 2) I have the book "code complete", which I am working through. 3) I have pointed some tools like "tattletale" at the code to get some diagrams of dependency relationships. What other strategies should I employ, should I focus on one particular aspect?

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• capistrano put() and upload() both failing

  - by Kyle

  With capistrano, I am deploying a Rails application from Mac OS X 10.5 to CentOS 5.2 Note that deploy.rb and the server environment have not changed in over a year. There is a task within our deploy.rb file called upload: put(File.read( file ),"#{shared_path}/#{filename}", :via => :scp) This fails each and every time with the following exception: No such file or directory - /srv/ourapp/releases/20100104194410/config/database.yml My local copy of config/database.yml is failing to upload properly. I've verified it's not our internet connection, as this happens on three different connections and two different systems. I've also tried to swap out put() for upload() but get the same result; also, dropping :via = :scp, and/or trying to force :sftp instead similarly fails. Relevant info: $ cap -V Capistrano v2.5.10 $ ruby -v ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin9.6.0]

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