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• Ruby - encrypted_strings

  - by Tom Andersen

  A bit of a Ruby newbie here - should be an easy question: I want to use the encrypted_strings gem to create a password encrypted string: (from http://rdoc.info/projects/pluginaweek/encrypted_strings) Question is: Everything works fine, but how come I don't need the password to decrypt the string? Say I want to store the string somewhere for a while,like the session. Is the password also stored with it? (which would seem very strange?). And no, I'm not planning on using 'secret-key' or any similar hack as a password. I am planning on dynamically generating a class variable @@password using a uuid, which I don't store other than in memory, and can change from one running of the program to the next. Symmetric: >> password = 'shhhh' => "shhhh" >> crypted_password = password.encrypt(:symmetric, :password => 'secret_key') => "qSg8vOo6QfU=\n" >> crypted_password.class => String >> crypted_password == 'shhhh' => true >> password = crypted_password.decrypt => "shhhh"

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• Which Java library for Binary Decision Diagrams?

  - by reprogrammer

  A Binary Decision Diagram (BDD) is a data structure to represent boolean functions. I'd like use this data structure in a Java program. My search for Java based BDD libraries resulted into the following packages. Java Decision Diagram Libraries JavaBDD JDD If you know of any other BDD libraries available for Java programs, please let me know so that I add it to the list above. If you have used any of these libraries, please tell me about your experience with the library. In particular, I'd like you to compare the available libraries along the following dimensions. Quality. Is the library mature and reasonably bug free? Performance. How do you evaluate the performance of the library? Support. Could you easily get support whenever you encountered a problem with the library? Was the library well documented? Ease of use. Was the API well designed? Could you install and use the library quickly and easily? Please mention the version of the library that you are evaluating.

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• Script to copy files on CD and not on hard disk to a new directory

  - by John22

  I need to copy files from a set of CDs that have a lot of duplicate content, with each other, and with what's already on my hard disk. The file names of identical files are not the same, and are in sub-directories of different names. I want to copy non-duplicate files from the CD into a new directory on the hard disk. I don't care about the sub-directories - I will sort it out later - I just want the unique files. I can't find software to do that - see my post at SuperUser http://superuser.com/questions/129944/software-to-copy-non-duplicate-files-from-cd-dvd Someone at SuperUser suggested I write a script using GNU's "find" and the Win32 version of some checksum tools. I glanced at that, and have not done anything like that before. I'm hoping something exists that I can modify. I found a good program to delete duplicates, Duplicate Cleaner (it compares checksums), but it won't help me here, as I'd have to copy all the CDs to disk, and each is probably about 80% duplicates, and I don't have room to do that - I'd have to cycle through a few at a time copying everything, then turning around and deleting 80% of it, working the hard drive a lot. Thanks for any help.

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• Base class deleted before subclass during python __del__ processing

  - by Oddthinking

  Context I am aware that if I ask a question about Python destructors, the standard argument will be to use contexts instead. Let me start by explaining why I am not doing that. I am writing a subclass to logging.Handler. When an instance is closed, it posts a sentinel value to a Queue.Queue. If it doesn't, a second thread will be left running forever, waiting for Queue.Queue.get() to complete. I am writing this with other developers in mind, so I don't want a failure to call close() on a handler object to cause the program to hang. Therefore, I am adding a check in __del__() to ensure the object was closed properly. I understand circular references may cause it to fail in some circumstances. There's not a lot I can do about that. Problem Here is some simple example code: explicit_delete = True class Base: def __del__(self): print "Base class cleaning up." class Sub(Base): def __del__(self): print "Sub-class cleaning up." Base.__del__(self) x = Sub() if explicit_delete: del x print "End of thread" When I run this I get, as expected: Sub-class cleaning up. Base class cleaning up. End of thread If I set explicit_delete to False in the first line, I get: End of thread Sub-class cleaning up. Exception AttributeError: "'NoneType' object has no attribute '__del__'" in <bound method Sub.__del__ of <__main__.Sub instance at 0x00F0B698>> ignored It seems the definition of Base is removed before the x._del_() is called. The Python Documentation on _del_() warns that the subclass needs to call the base-class to get a clean deletion, but here that appears to be impossible. Can you see where I made a bad step?

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• Can I ignore a SIGFPE resulting from division by zero?

  - by Mikeage

  I have a program which deliberately performs a divide by zero (and stores the result in a volatile variable) in order to halt in certain circumstances. However, I'd like to be able to disable this halting, without changing the macro that performs the division by zero. Is there any way to ignore it? I've tried using #include <signal.h> ... int main(void) { signal(SIGFPE, SIG_IGN); ... } but it still dies with the message "Floating point exception (core dumped)". I don't actually use the value, so I don't really care what's assigned to the variable; 0, random, undefined... EDIT: I know this is not the most portable, but it's intended for an embedded device which runs on many different OSes. The default halt action is to divide by zero; other platforms require different tricks to force a watchdog induced reboot (such as an infinite loop with interrupts disabled). For a PC (linux) test environment, I wanted to disable the halt on division by zero without relying on things like assert.

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• How do I process the configure file when cross-compiling with mingw?

  - by vy32

  I have a small open source program that builds with an autoconf configure script. I ran configure I tried to compile with: make CC="/opt/local/bin/i386-mingw32-g++" That didn't work because the configure script found include files that were not available to the mingw system. So then I tried: ./configure CC="/opt/local/bin/i386-mingw32-g++" But that didn't work; the configure script gives me this error: ./configure: line 5209: syntax error near unexpected token `newline' ./configure: line 5209: ` *_cv_*' Because of this code: # The following way of writing the cache mishandles newlines in values, # but we know of no workaround that is simple, portable, and efficient. # So, we kill variables containing newlines. # Ultrix sh set writes to stderr and can't be redirected directly, # and sets the high bit in the cache file unless we assign to the vars. ( for ac_var in `(set) 2>&1 | sed -n 's/^\(a-zA-Z_a-zA-Z0-9_*\)=.*/\1/p'`; do eval ac_val=\$$ac_var case $ac_val in #( *${as_nl}*) case $ac_var in #( *_cv_* fi Which is generated then the AC_OUTPUT is called. Any thoughts? Is there a correct way to do this?

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• Deployment Setup (.Net) - Search target machine -> Registry search (64 bit)

  - by Joonas Kirsebom

  I have a windows installer project which installs some software (winform, service, mce addin). During the installation I need to search the machine for a registry key. This is done with with the "Launch Condition" - "Add Registry Search" (Deployment Project). I have filled out all the properties right, and checked against the regestry that the value actually can be found. The problem is that the "Registry Search" searches in the x86 part of the registry (HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\...) although my system is a x64 and the deployment setup is also set to x64. Does anyone know how to force the "Registry Search" to search the x64 registry? Or know about a workaround? The weird thing about this, is that Registry setting in the deployment setup is writing to the right registry (x64). My idea is that the "Registry Search" program is only developed to the x86 architecture, and therefore can't read the right registry. I found this article from microsoft, so it seams that they know about this problem. https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=110105&wa=wsignin1.0#details My system is: Windows 7 64bit Visual Studio 2008

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• Debugging fortran code in Eclipse with Photran and GDB debugger: missing symbols

  - by tvandenbrande

  I have a program, written in fortran90, previously successfully compiled on a compaq compiler and working, that I'm now trying to compile with gfortran. I can compile the code to an .exe and run it. It works fine until a certain point in the routine and then an error is thrown. My current configuration: Windows 7 Eclipse Juno with CDT Photran Cygwin installation with gfortran compiler and GDB debugger (gdb.exe) Configurations for the debugger: GDB command set: Standard (Windows) Protocol: mi Shared libraries: don't load shared library symbols automatically (when activating this, no changes are noted). When running the debug command I get the following output: .gdbinit: No such file or directory. Reading symbols from /cygdrive/c/Users/thys/Documents/doctoraat/12_in progress/Hamfem/Debug/Hamfem.exe...done. auto-solib-add on Undefined command: "auto-solib-add". Try "help". Warning: C:/Users/thys/Documents/doctoraat/12_in progress/Hamfem/Hamfem/in: No such file or directory. [New Thread 5816.0x1914] [New Thread 5816.0x654] Basicly that leaves me with 2 questions: Where can I find the .gdbinit file in the cygwin installation? Are there any other possible errors in my setup, or points to think about?

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• Check if files in a directory are still being written using Windows Batch Script

  - by FMFF

  Hello. Here's my batch file to parse a directory, and zip files of certain type REM Begin ------------------------ tasklist /FI "IMAGENAME eq 7za.exe" /FO CSV > search.log FOR /F %%A IN (search.log) DO IF %%~zA EQU 0 GOTO end for /f "delims=" %%A in ('dir C:\Temp\*.ps /b') do ( "C:\Program Files\7-Zip\cmdline\7za.exe" a -tzip -mx9 "C:\temp\Zip\%%A.zip" "C:\temp\%%A" Move "C:\temp\%%A" "C:\Temp\Archive" ) :end del search.log REM pause exit REM End --------------------------- This code works just fine for 90% of my needs. It will be deployed as a scheduled task. However, the *.ps files are rather large (minimum of 1GB) in real time cases. So the code is supposed to check if the incoming file is completely written and is not locked by the application that is writing it. I saw another example elsewhere, that suggested the following approach :TestFile ren c:\file.txt c:\file.txt if errorlevel 0 goto docopy sleep 5 goto TestFile :docopy However this example is good for a fixed file. How can I use that many labels and GoTo's inside a for loop without causing an infinite loop? Or is this code safe to be used in the For Loop? Thank you for any help.

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• Creating a class Hierarchy for Atoms,neutrons,protons,chemical reationc

  - by Smart Zulu

  I need help to create a program that can show the hierarchy of any Atoms and its components (neutrons,protons,electrons,and chemical reaction) Here is a code of what i have done so far,being a novice at the subject using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Atoms { public class Atoms { protected string name = "Sodium"; protected string element ="Metal"; public virtual void GetInfo() { Console.WriteLine("name: {0}",name); Console.WriteLine("element: {0}", element); } } class Proton : Atoms { public int number = 11 ; public override void GetInfo() { base.GetInfo(); Console.WriteLine("Proton number: {0}",number); } } class Electron : Atoms { public int number = 11; public override void GetInfo() { base.GetInfo(); Console.WriteLine("Electron number: {0}", number); } class Neutrons : Atoms { public int number = 12; public override void GetInfo() { base.GetInfo(); Console.WriteLine("Neutron number: {0}", number); } class TestClass { static void Main() { Proton P = new Proton(); P.GetInfo(); Neutrons N = new Neutrons(); N.GetInfo(); Electron E = new Electron(); E.GetInfo(); Console.WriteLine("click any key to exit"); Console.ReadLine(); } } } } }

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• Will the following NHibernate interface mapping work?

  - by Ben Aston

  I'd like to program against interfaces when working with NHibernate due to type dependency issues within the solution I am working with. SO questions such as this indicate it is possible. I have an ILocation interface and a concrete Location type. Will the following work? HBM mapping: <class name="ILocation" abstract="true" table="ILocation"> <id name="Id" type="System.Guid" unsaved-value="00000000-0000-0000-0000-000000000000"> <column name="LocationId" /> <generator class="guid" /> </id> <union-subclass table="Location" name="Location"> <property name="Name" type="System.String"/> </union-subclass> </class> Detached criteria usage using the interface: var criteria = DetachedCriteria.For<ILocation>().Add(Restrictions.Eq("Name", "blah")); var locations = criteria.GetExecutableCriteria(UoW.Session).List<ILocation>(); Are there any issues with not using the hilo ID generator and/or with this approach in general?

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• How to get debugging of an App Engine application working?

  - by Chris Lacy

  I've got 10+ years in C/C++, and it appears Visual Studio has spoilt me during that time. In Visual Studio, debbuging issimple: I just add a breakpoint to a line of code, and as soon as that code is executed, my breakpoint triggers, at which point I can view a callstack, local/member variables, etc. I'm trying to achieve this functionality under App Engine. I assume that is possible? All the searching I've done to this point has led me to using Pydev in Eclipse. As best I can tell, I am successfully launching my simple 'hello world' program in Debug mode. But the IDE doesn't even seem to have an option to set a breakpoint? I must be missing something. I've googled long and hard about this, but am having no luck. Most results trace back to the same old threads that don't deal directly with my issue. Can anyone shed some light on how you get basic debugging setup using Pydev/Eclipse with App Engine? Alternatively, if there's an easier way to debug App Engine than using Pydev/Eclipse, I'd love to hear about it. Thanks in advance.

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• How to deserialize an element as an XmlNode?

  - by mackenir

  When using Xml serialization in C#, I want to deserialize a part of my input XML to an XmlNode. So, given this XML: <Thing Name="George"> <Document> <subnode1/> <subnode2/> </Document> </Thing> I want to deserialize the Document element to an XmlNode. Below is my attempt which given the XML above, sets Document to the 'subnode1' element rather than the 'Document' element. How would I get the code to set the Document property to the Document element? using System; using System.IO; using System.Xml; using System.Xml.Serialization; [Serializable] public class Thing { [XmlAttribute] public string Name {get;set;} public XmlNode Document { get; set; } } class Program { static void Main() { const string xml = @" <Thing Name=""George""> <Document> <subnode1/> <subnode2/> </Document> </Thing>"; var s = new XmlSerializer(typeof(Thing)); var thing = s.Deserialize(new StringReader(xml)) as Thing; } } However, when I use an XmlSerializer to deserialize the XML above to an instance of Thing, the Document property contains the child element 'subnode1', rather than the 'doc' element. How can I get the XmlSerializer to set Document to an XmlNode containing the 'doc' element.

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• Java and .net interoperability

  - by dineshrekula

  I have a c# program through which i am opening cmd window as a a process. in this command window i am running a batch file. i am redirecting the output of that batch file commands to a Text File. When i run my application everything seems to be ok. But few times, Application is giving some error like "Can't access the file. it's being used by another application" at the same time cmd window is not getting closed. If we close the cmd process through the Task Manager, then it's writing the content to the file and getting closed. Even though i closed the cmd process, still file handle is not getting released. so that i am not able to run the application next time onwards.Always it's saying Can't access the file. Only after restarting the system, it's working. Here is my code: Process objProcess = new Process(); ProcessStartInfo objProInfo = new ProcessStartInfo(); objProInfo.WindowStyle = ProcessWindowStyle.Maximized; objProInfo.UseShellExecute = true; objProInfo.FileName = "Batch file path" objProInfo.Arguments = "Some Arguments"; if (Directory.Exists(strOutputPath) == false) { Directory.CreateDirectory(strOutputPath); } objProInfo.CreateNoWindow = false; objProcess.StartInfo = objProInfo; objProcess.Start(); objProcess.WaitForExit(); test.bat: java classname argument > output.txt Here is my question: I am not able to trace where the problem is.. How we can see the process which holding handle on ant file. Is there any suggestions for Java and .net interoperability

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• Ways to gain a deeper understanding of programming concepts?

  - by MrPlow

  I'm a marketer and have been messing around in PHP/MySQL for years. Recently (the last several months) I've been making my own scripts/programs in Python and I've really enjoyed the whole problem solving process. I've read(skimmed) some books and understand the basics of OOP, polymorphism, etc.. I have a general interest in AI and Natural Language in particular but it seems these things require a masters in Computer Science. My knowledge of math is poor. The last class I took was calculus, and I've forgotten the majority of it. Basically I'm looking for things to learn that will help me think in a more analytic way, and maybe see solutions where I didn't before. Improving my ability to program in Python would be nice too. I don't need to learn a specific language or something for employment, just enjoyment. Although my work often involves web development so some utility would be nice. I don't like learning concepts by just reading them. I need to apply them, even if the examples are contrived. A recommendation of a couple good books or other resources would be nice. :) Apologies if this is too vague/misplaced...

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• How to call Twiter's Streaming/Filter Feed with urllib2/httplib?

  - by Simon

  Update: I switched this back from answered as I tried the solution posed in cogent Nick's answer and switched to Google's urlfetch: logging.debug("starting urlfetch for http://%s%s" % (self.host, self.url)) result = urlfetch.fetch("http://%s%s" % (self.host, self.url), payload=self.body, method="POST", headers=self.headers, allow_truncated=True, deadline=5) logging.debug("finished urlfetch") but unfortunately finished urlfetch is never printed - I see the timeout happen in the logs (it returns 200 after 5 seconds), but execution doesn't seem tor return. Hi All- I'm attempting to play around with Twitter's Streaming (aka firehose) API with Google App Engine (I'm aware this probably isn't a great long term play as you can't keep the connection perpetually open with GAE), but so far I haven't had any luck getting my program to actually parse the results returned by Twitter. Some code: logging.debug("firing up urllib2") req = urllib2.Request(url="http://%s%s" % (self.host, self.url), data=self.body, headers=self.headers) logging.debug("called urlopen for %s %s, about to call urlopen" % (self.host, self.url)) fobj = urllib2.urlopen(req) logging.debug("called urlopen") When this executes, unfortunately, my debug output never shows the called urlopen line printed. I suspect what's happening is that Twitter keeps the connection open and urllib2 doesn't return because the server doesn't terminate the connection. Wireshark shows the request being sent properly and a response returned with results. I tried adding Connection: close to my request header, but that didn't yield a successful result. Any ideas on how to get this to work? thanks -Simon

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• J2ME cache issue

  - by kiennt

  I have to write a J2ME app to retrieve images from server and display in mobile phone. I have seen and test that Snaptu have a mechanism to cache image, event with 100 images (both normal size and zoom size). I wonder how they can do that? I though that those guys use rms to save image stream to data. But when i check in working folder of simulater( I use Windows XP and Sun Wireless Toolkit 3.0, the Emulator device i use to run my program is CLDC Device 1 - my working folder is C:\Document And Settings\Administrator\javame-sdk\3.0\work\6\appdb), i see some .db file. When i delete these files, i still can view cache image in my emulator???? I also thought that those guys use heap memory to save image. But it is not correct because when i set limit device memory is 2MB (like some mobile phones), and i load and view 100 images in zoom size, it didn't make OutOfMemory Error? It so weird. Any one can help me? Thanks

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• Can addition of an ActionListener be short? Can I add arguments to the actionPerformed?

  - by Roman

  I have a big table containing a button in each cell. These buttons are very similar and do almost the same. If I add an action listener to every button in this way: tmp.addActionListener(new ActionListener(){ @Override public void actionPerformed(ActionEvent evt) { proposition = proposition + action; SwingUtilities.invokeLater(new Runnable() { public void run() { updatePropositionPanel(); } }); } }); Actually, every action listener differ from all others by the value of the action. proposition and updatePropositionPanel are a field and a method of the class. First i thought that I can make it shorter if I do not use inner classes. So, I decided to program a new ActionListener class. But than I realized that in this case "proposition" will not be visible to the instances of this class. Then I decided to add the actionPerformed method to the current class and do that: addActionListener(this). But than I realized that I do not know how give arguments to the actionPerformed method. So, how does it work. Can I add an action listener in a short and elegent way?

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• How to convert a printer driver to a stand-alone console application which can generate a printer fi

  - by Thorbjørn Ravn Andersen

  I have a situation where the only way to generate a certain datafile is to print it manually to FILE: under Windows and save it in a file for further processing. I would really like to have a small stand-alone program which embeds this binary printer driver so I can run it from a batch file and have it generate that binary file for me, as we can then fully automate the "save file in Visio, 'print' it and upload it to the final destination and trigger a remote test". Is this possible with a suitable Windows SDK? I am a Java programmer, so I do not know Visual Studio and the possibilities with MSDN - yet! - but I'd appreciate pointers. EDIT: I have the installation files for that printer driver, both 32 and 64 bit. Older versions may include a 16 bit driver. EDIT: The "print to FILE:" functionality is just what was recommended by the documentation. I have played a little bit with using the LPR-protocol to see what it can do. I'd still prefer the "invoke small binary" approach.

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• Java: Exception in thread main java.lang.NoClassDefFoundError

  - by cath

  I am trying to get the Red5 Flash Media Server working on my computer. I have installed it, but when I run the server I get this error Exception in thread "main" java.lang.NoClassDefFoundError: org/red5/server/Bootstrap Caused by: java.lang.ClassNotFoundException: org.red5.server.Bootstrap at java.net.URLClassLoader$1.run(URLClassLoader.java:217) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at java.lang.ClassLoader.loadClass(ClassLoader.java:321) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) at java.lang.ClassLoader.loadClass(ClassLoader.java:266) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:334) Could not find the main class: org.red5.server.Bootstrap. Program will exit. I came across this link where someone had the same issue: http://trac.red5.org/ticket/762 It looks like they ran this command: export CLASSPATH=3D$RED5_HOME/lib/slf4j-api-1.5.10.jar:$RED5_HOME/lib/logback- core-0.9.18.jar:$RED5_HOME/lib/logback-classic-0.9.18.jar I have red5 installed in /usr/share/red5, so I ran this: export CLASSPATH=3D$/usr/share/red5/lib/slf4j-api-1.5.10.jar:$/usr/share/red5/lib/logback-core-0.9.18.jar:$/usr/share/red5/lib/logback-classic-0.9.18.jar Yet despite all this I am still seeing the same error message.

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• Can I use manifests to consume a COM server without specifying its version?

  - by sharptooth

  Two of our programs use the same COM server (also made by us) with the same class ids. Each program when installing copies the COM server files into its folder and regsvr32s the COM server. The problem is how to install the COM server so that the user can install either one or both of our programs into different folders in any order and likely of different versions. Clearly it's impossible without changing the class ids and that's lots of hassle with configurations. Ideally we would like to use manifests for that and go without regsvr32. The problem is every time I read about reg-free COM (for example, here) there's the version attribute in the assemblyIdentity. The version number should change every nightly build and I totally don't like the idea of (automatically) adjusting it. I understand why specifying dependency on a specific version is good, but it's completely useless in our scenarion. Is there a way to write manifests for both the COM server and the consumer so that they don't specify versions and just work with whatever version of the file happens to be in the folder? Also is there a way to restrict the search to the same folder as the consumer?

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• Python subprocess Popen.communicate() equivalent to Popen.stdout.read()?

  - by Christophe

  Very specific question (I hope): What are the differences between the following three codes? (I expect it to be only that the first does not wait for the child process to be finished, while the second and third ones do. But I need to be sure this is the only difference...) I also welcome other remarks/suggestions (though I'm already well aware of the shell=True dangers and cross-platform limitations) Note that I already read Python subprocess interaction, why does my process work with Popen.communicate, but not Popen.stdout.read()? and that I do not want/need to interact with the program after. Also note that I already read Alternatives to Python Popen.communicate() memory limitations? but that I didn't really get it... First code: from subprocess import Popen, PIPE def exe_f(command='ls -l', shell=True): "Function to execute a command and return stuff" process = Popen(command, shell=shell, stdout=PIPE, stderr=PIPE) stdout = process.stdout.read() stderr = process.stderr.read() return process, stderr, stdout Second code: from subprocess import Popen, PIPE from subprocess import communicate def exe_f(command='ls -l', shell=True): "Function to execute a command and return stuff" process = Popen(command, shell=shell, stdout=PIPE, stderr=PIPE) (stdout, stderr) = process.communicate() return process, stderr, stdout Third code: from subprocess import Popen, PIPE from subprocess import wait def exe_f(command='ls -l', shell=True): "Function to execute a command and return stuff" process = Popen(command, shell=shell, stdout=PIPE, stderr=PIPE) code = process.wait() stdout = process.stdout.read() stderr = process.stderr.read() return process, stderr, stdout Thanks.

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• Code bacteria: evolving mathematical behavior

  - by Stefano Borini

  It would not be my intention to put a link on my blog, but I don't have any other method to clarify what I really mean. The article is quite long, and it's in three parts (1,2,3), but if you are curious, it's worth the reading. A long time ago (5 years, at least) I programmed a python program which generated "mathematical bacteria". These bacteria are python objects with a simple opcode-based genetic code. You can feed them with a number and they return a number, according to the execution of their code. I generate their genetic codes at random, and apply an environmental selection to those objects producing a result similar to a predefined expected value. Then I let them duplicate, introduce mutations, and evolve them. The result is quite interesting, as their genetic code basically learns how to solve simple equations, even for values different for the training dataset. Now, this thing is just a toy. I had time to waste and I wanted to satisfy my curiosity. however, I assume that something, in terms of research, has been made... I am reinventing the wheel here, I hope. Are you aware of more serious attempts at creating in-silico bacteria like the one I programmed? Please note that this is not really "genetic algorithms". Genetic algorithms is when you use evolution/selection to improve a vector of parameters against a given scoring function. This is kind of different. I optimize the code, not the parameters, against a given scoring function.

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• Only last row in method execute (Objective-C)

  - by Emil

  First I want to apologize for my lack of knowledge in programming in general. I am in the way of learning and have discovered that this site is a huge compliment for me of doing so. I have created a program with three UITextField(thePlace,theVerb,theOutput) and two UITextView where one of the textviews(theOutput) take the text from the other textview(theTemplate) and replaces some strings with the text entered in the textfields. When I click a button it triggers the method createStory that is listed below. This works fine with one exception. The text in the output only changes the string 'number' to the text in the textfield. However if I change the order in the method to replace 'place','number','verb' only the verb is changed, not the number. Im sure this is some sort of easy fix but I can't find it. Can some of you help me with my troubleshooting? - (IBAction)createStory:(id)sender { theOutput.text=[theTemplate.text stringByReplacingOccurrencesOfString:@"<place>" withString:thePlace.text]; theOutput.text=[theTemplate.text stringByReplacingOccurrencesOfString:@"<verb>" withString:theVerb.text]; theOutput.text=[theTemplate.text stringByReplacingOccurrencesOfString:@"<number>" withString:theNumber.text]; } Many thanks // Emil

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• Why does autoboxing in Java allow me to have 3 possible values for a boolean?

  - by John

  Reference: http://java.sun.com/j2se/1.5.0/docs/guide/language/autoboxing.html If your program tries to autounbox null, it will throw a NullPointerException. javac will give you a compile-time error if you try to assign null to a boolean. makes sense. assigning null to a Boolean is a-ok though. also makes sense, i guess. but let's think about the fact that you'll get a NPE when trying to autounbox null. what this means is that you can't safely perform boolean operations on Booleans without null-checking or exception handling. same goes for doing math operations on an Integer. for a long time, i was a fan of autoboxing in java1.5+ because I thought it got java closer to be truly object-oriented. but, after running into this problem last night, i gotta say that i think this sucks. the compiler giving me an error when I'm trying to do stuff with an uninitialized primitive is a good thing. I think I may be misunderstanding the point of autoboxing, but at the same time I will never accept that a boolean should be able to have 3 values. can anyone explain this? what am i not getting?

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