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  • python: using __import__ to import a module which in turn generates an ImportError

    - by bbb
    Hi there, I have a funny problem I'd like to ask you guys ('n gals) about. I'm importing some module A that is importing some non-existent module B. Of course this will result in an ImportError. This is what A.py looks like import B Now let's import A >>> import A Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/tmp/importtest/A.py", line 1, in <module> import B ImportError: No module named B Alright, on to the problem. How can I know if this ImportError results from importing A or from some corrupt import inside A without looking at the error's string representation. The difference is that either A is not there or does have incorrect import statements. Hope you can help me out... Cheers bb

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  • Basic Recursion, Check Balanced Parenthesis

    - by pws5068
    Greetings all, I've written software in the past that uses a stack to check for balanced equations, but now I'm asked to write a similar algorithm recursively to check for properly nested brackets and parenthesis. Good examples: () [] () ([]()[]) Bad examples: ( (] ([)] Suppose my function is called: isBalanced. Should each pass evaluate a smaller substring (until reaching a base case of 2 left)? Or, should I always evaluate the full string and move indices inward?

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  • Help me understand Inorder Traversal without using recursion

    - by vito
    I am able to understand preorder traversal without using recursion, but I'm having a hard time with inorder traversal. I just don't seem to get it, perhaps, because I haven't understood the inner working of recursion. This is what I've tried so far: def traverseInorder(node): lifo = Lifo() lifo.push(node) while True: if node is None: break if node.left is not None: lifo.push(node.left) node = node.left continue prev = node while True: if node is None: break print node.value prev = node node = lifo.pop() node = prev if node.right is not None: lifo.push(node.right) node = node.right else: break The inner while-loop just doesn't feel right. Also, some of the elements are getting printed twice; may be I can solve this by checking if that node has been printed before, but that requires another variable, which, again, doesn't feel right. Where am I going wrong? I haven't tried postorder traversal, but I guess it's similar and I will face the same conceptual blockage there, too. Thanks for your time! P.S.: Definitions of Lifo and Node: class Node: def __init__(self, value, left=None, right=None): self.value = value self.left = left self.right = right class Lifo: def __init__(self): self.lifo = () def push(self, data): self.lifo = (data, self.lifo) def pop(self): if len(self.lifo) == 0: return None ret, self.lifo = self.lifo return ret

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  • boost::Spirit Grammar for unsorted schema

    - by Hassan Syed
    I have a section of a schema for a model that I need to parse. Lets say it looks like the following. { type = "Standard"; hostname="x.y.z"; port="123"; } The properties are: The elements may appear unordered. All elements that are part of the schema must appear, and no other. All of the elements' synthesised attributes go into a struct. (optional) The schema might in the future depend on the type field -- i.e., different fields based on type -- however I am not concerned about this at the moment.

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  • Ignore errors when scanning for files in C:\

    - by Shane
    I am trying to search the C:\ drive for all files with a certain extension. I am using the following code which is working fine, however when it encounters an error the whole process stops rather than continuing with the scan. (running in backgroundworker, hence the invoke) Private Sub ScanFiles(ByVal rootFolder As String, ByVal fileExtension As String) 'Determine if the current folder contains any sub folders Dim subFolders() As String = System.IO.Directory.GetDirectories(rootFolder) For Each subFolder As String In subFolders ScanFiles(subFolder, fileExtension) Next For Each file As String In System.IO.Directory.GetFiles(rootFolder, fileExtension) lb.BeginInvoke(New AddValue(AddressOf AddItems), file) Next End Sub How can I make this code continue once an error is encountered? Thanks for your help.

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  • Parse Directory Structure (Strings) to JSON using PHP

    - by Ecropolis
    I have an array of file-path strings like this videos/funny/jelloman.wmv videos/funny/bellydance.flv videos/abc.mp4 videos/june.mp4 videos/cleaver.mp4 fun.wmv jimmy.wmv herman.wmv Is there a library or easy way I can get to a data structure json or xml? Something like this: (I see there are a lot of snippets available for traversing actual folders, but again, I just have strings.) { files:{ file:[ { filename:'fun.wmv' }, { filename:'jimmy.wmv' }, { filename:'herman.wmv' } ], folder:{ foldername:'videos', file:[ { filename:'abc.mp4' }, { filename:'june.mp4' }, { filename:'cleaver.mp4' } ], folder:{ foldername:'funny', file:[ { filename:'jelloman.wmv' }, { filename:'bellydance.flv' } ] } } } }

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  • How can I write an XSLT that will recursively include other files?

    - by Eric
    Let's say I have a series of xml files in this format: A.xml: <page> <header>Page A</header> <content>blAh blAh blAh</content> </page> B.xml: <page also-include="A.xml"> <header>Page B</header> <content>Blah Blah Blah</content> </page> Using this XSLT: <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/page"> <h1> <xsl:value-of select="header" /> </h1> <p> <xsl:value-of select="content" /> </p> </xsl:template> </xsl:stylesheet> I can turn A.xml into this: <h1> Page A </h1> <p> blAh blAh blAh </p> But how would I make it also turn B.xml into this? <h1> Page B </h1> <p> Blah Blah Blah </p> <p> blAh blAh blAh </p> I know that I need to use document(concat(@also-include,'.xml')) somewhere, but I'm not sure where. Oh, and the catch is, I need this to still work if B were to be included in a third file, C.xml. Any idea as to how to do this?

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  • In terminal, merging multiple folders into one.

    - by Josh Pinter
    I have a backup directory created by WDBackup (western digital external HD backup util) that contains a directory for each day that it backed up and the incremental contents of just what was backed up. So the hierarchy looks like this: 20100101 My Documents Letter1.doc My Music Best Songs Every First Songs.mp3 My song.mp3 # modified 20100101 20100102 My Documents Important Docs Taxes.doc My Music My Song.mp3 # modified 20100102 ...etc... Only what has changed is backed up and the first backup that was ever made contains all the files selected for backup. What I'm trying to do now is incrementally copy, while keeping the folder structure, from oldest to newest, each of these dated folders into a 'merged' folder so that it overrides the older content and keeps the new stuff. As an example, if just using these two example folders, the final merged folder would look like this: Merged My Documents Important Docs Taxes.doc Letter1.doc My Music Best Songs Every First Songs.mp3 My Song.mp3 # modified 20100102 Hope that makes sense. Thanks, Josh

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  • how can we make class with Linked list recursion ...

    - by epsilon_G
    Hi , I'm newbee in The C++ heaven and the OOP, ... I'd like to make some stuffs with the Data structures ... However,I'd like to merge two linked listes ... I made a class before "List" wich contain all what I need to programme something with List ... Add , Display .. The probleme is that I programmed the function "Merge2lists" which give us the third list .. How can I display the third list in the main program after using "Merge2lists" Plz , my prob with the Class and the OOP syntaxe ... try to give me the implementation in the main program ??? Otherwise,How can I apply function given pointer in main program wich declared in class .. Thankx class Liste { private: struct node { int elem ; node *next; }*p; public: LLC(); void Merge2lists (node* a, node * b,node *&result); ~LLC(); }; void List::Merge2lists (node* a, node * b,node *&result) { result = NULL; if (a==NULL) { result=b; return;} else if (b==NULL) { result=a; return;} if (a->elem <= b->elem) { result = a; Merge2lists(a->next, b,result->next); } else { result = b; Merge2lists(a, b->next,result->next); } return; } int main() { liste a ; a.Aff_Val(46); a.Aff_Val(54); a.add_as_first(2); a.add_as_first(1); a.Display(); /*This to displat the elemnts ... Don't care about it it's easy to make*/ list liste2; b.Add(2); b.Add(14); b.Add(16); list result; Merge2lists (a,b,result); /*The probleme is here , how can I use this in my program */

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  • Maven: trying to get my submodule's poms to NOT inherit a plugin in the parent

    - by jobrahms
    My project has a parent pom and several submodule poms. I've put a plugin in the parent that is responsible for building our installer distributables (using install4j). It doesn't make sense to have this plugin run on the submodules, so I've put false in the plugin's config, as seen below. The problem is, when I run mvn clean install install4j:compile it cleans, compiles, and runs the install4j plugin on the parent, but then it tries to run it on the child modules and crashes. Here's the plugin config <plugin> <groupId>com.google.code.maven-install4j</groupId> <artifactId>maven-install4j-plugin</artifactId> <version>0.1.1</version> <inherited>false</inherited> <configuration> <executable>${devenv.install4jc}</executable> <configFile>${basedir}/newinstaller/ehd-demo.install4j</configFile> <releaseId>${project.version}</releaseId> <attach>false</attach> <skipOnMissingExecutable>true</skipOnMissingExecutable> </configuration> </plugin> Am I misunderstanding the purpose of inherited=false? What is the correct way to get this to work? I'm using maven 2.2.0.

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  • Display `pretty output` of directory content from array

    - by user275074
    Hi, I'm using the following code to get an array of directories and their sub-directories where each contain file type extension: png. It works great but I need to be able to output the results of the array in a list style format e.g. Test - test2.png - test1.png subfolder - test3.png sub sub folder - test4.png etc Code: $filter=".png"; $directory='../test'; $it=new RecursiveDirectoryIterator("$directory"); foreach(new RecursiveIteratorIterator($it) as $file){ if(!((strpos(strtolower($file),$filter))===false)||empty($filter)){ $items[]=preg_replace("#\\\#", "/", $file); } } Example array of results: array ( 0 => '../test/test2.png', 1 => '../test/subfolder/subsubfolder/test3.png', 2 => '../test/subfolder/test3.png', 3 => '../test/test1.png', ) What would be the best way of achieving the desired result?

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  • How can invoke a shell to make a new environment to run a make inside another make?

    - by WilliamKF
    I would like in my GNUmakefile to have a target rule that invokes a new shell and then with the clean slate of the new shell invokes a new make. What is the syntax to do this? I tried this but it didn't work: .PHONY: setup setup: shell cd myDir; make; cd .. It gets infinite repeat of the following error: make[1]: Entering directory `/disk4/home/user/parent' shell cd myDir; make; cd .. /bin/sh: shell: command not found make[1]: Entering directory `/disk4/home/user/parent' shell cd myDir; make; cd .. /bin/sh: shell: command not found [...]

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  • Whats the python way for recursively setting file permissions?

    - by Geoff
    What's the "python way" to recursively set the owner and group to files in a directory? I could just pass a 'chown -R' command to shell, but I feel like I'm missing something obvious. I'm mucking about with this: import os path = "/tmp/foo" for root, dirs, files in os.walk(path): for momo in dirs: os.chown(momo, 502, 20) This seems to work for setting the directory, but fails when applied to files. I suspect the files are not getting the whole path, so chown fails since it can't find the files. The error is: 'OSError: [Errno 2] No such file or directory: 'foo.html' What am I overlooking here?

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  • python: importing modules with incorrect import statements => unexhaustive info from resulting Impor

    - by bbb
    Hi there, I have a funny problem I'd like to ask you guys ('n gals) about. I'm importing some module A that is importing some non-existent module B. Of course this will result in an ImportError. This is what A.py looks like import B Now let's import A >>> import A Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/tmp/importtest/A.py", line 1, in <module> import B ImportError: No module named B Alright, on to the problem. How can I know if this ImportError results from importing A or from some corrupt import inside A without looking at the error's string representation. The difference is that either A is not there or does have incorrect import statements. Hope you can help me out... Cheers bb

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  • Best way to blend colors in tile lighting? (XNA)

    - by Lemoncreme
    I have made a color, decent, recursive, fast tile lighting system in my game. It does everything I need except one thing: different colors are not blended at all: Here is my color blend code: return (new Color( (byte)MathHelper.Clamp(color.R / factor, 0, 255), (byte)MathHelper.Clamp(color.G / factor, 0, 255), (byte)MathHelper.Clamp(color.B / factor, 0, 255))); As you can see it does not take the already in place color into account. color is the color of the previous light, which is weakened by the above code by factor. If I wanted to blend using the color already in place, I would use the variable blend. Here is an example of a blend that I tried that failed, using blend: return (new Color( (byte)MathHelper.Clamp(((color.R + blend.R) / 2) / factor, 0, 255), (byte)MathHelper.Clamp(((color.G + blend.G) / 2) / factor, 0, 255), (byte)MathHelper.Clamp(((color.B + blend.B) / 2) / factor, 0, 255))); This color blend produces inaccurate and strange results. I need a blend that is accurate, like the first example, that blends the two colors together. What is the best way to do this?

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  • Where to put a recursive function when following MVC?

    - by Glibly
    Hello, I have a recursive function being used to generate a menu on my site. The function is calling a database for each level of children in the menu, and generating html for them. I've currently put this function in a Model part of the code, however, I feel that generating html in the model goes against the MVC. I didn't put it in a Controller because I didn't want to have database calls or HTML generation there. I didn't put it in a View because I didn't want database calls there either. Is the 'correct' way of tackling this problem to have a Controller call a recursive function in a Model that returns a 2d array representing the menu. Then pass the array to a view which has it's own recursive function for generating html from the array?

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  • Can a PL/pgSQL function contain a dynamic subquery?

    - by morpheous
    I am writing a PL/pgSQL function. The function has input parameters which specify (indirectly), which tables to read filtering information from. The function embeds business logic which allows it to select data from different tables based on the input arguments. The function dynamically builds a subquery which returns filtering data which is then used to run the main query. My questions are: Is it 'legal' to use a dynamic subquery in a PL/pgSQL function. I cant see why not - but this question is related to the next one. AFAIK, PL/pgSQL are cached or precompiled by the query engine. How does having a function that generates dynamic subqueries impact the work of the query engine?

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  • Returning a recordcount from a subquery in a result set.

    - by KeRiCr
    I am attempting to return a rowcount from a subquery as part of a result set. Here is a sample that I've tried that didn't work: SELECT recordID , GroupIdentifier , count() AS total , (SELECT COUNT() FROM table WHERE intActingAsBoolean = 1) AS Approved FROM table WHERE date_format(Datevalue, '%Y%m%d') BETWEEN 'startDate' AND 'endDate' GROUP BY groupIdentifier What I'm attempting to return for 'Approved' is the number of records for the grouped value where intActingAsBoolean = 1. I have also tried modifying the where clause by giving the main query a table alias and applying an AND clause to match the groupidentifier in the subquery to the main query. None of these are returning the correct results. The query as written returns all records in the table where intActingAsBoolean = 1. This query is being run against a MySQL database.

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  • How to write a recursive function that returns a linked list of nodes, when given a binary tree of n

    - by Jian Lin
    I was once asked of this in an interview: How to write a recursive function that returns a linked list of nodes, when given a binary tree of nodes? (flattening the data) For some reason, I tend to need more than 3 to 5 minutes to solve any recursive problem. Usually, 15 to 20 minutes will be more like it. How could we attack this problem, such as a very systematic way of reaching a solution, so that they can be solved in 3 to 5 minute time frame?

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  • To what extent is size a factor in SSD performance?

    - by artif
    To what extent is the size of an SSD a factor in its performance? In my mind, correct me if I'm wrong, a bigger SSD should be, everything else being equal, faster than a smaller one. A bigger SSD would have more erase blocks and thus more leeway for the FTL (flash translation layer) to do garbage collection optimization. Also there would be more time before TRIM became necessary. I see on Wikipedia that it remarks that "The performance of the SSD can scale with the number of parallel NAND flash chips used in the device" so it seems throughput also increases significantly. Also many SSDs contain internal caches of some sort and presumably those caches are larger for correspondingly large SSDs. But supposing this effect exists, I would like a quantitative analysis. Does throughput increase linearly? How much is garbage collection impacted, if at all? Does latency stay the same? And so on. Would the performance of a 8 GB SSD be significantly different from, for example, an 80 GB SSD assuming both used high quality chips, controllers, etc? Are there any resources (webpages, research papers, presentations, books, etc) that discuss correlations between SSD performance (4 KB random write speed, latency, maximum sequential throughput, etc) and size? I realize this does not really sound like a programming question but it is relevant for what I'm working on (using flash for caching hard drive data) which does involve programming. If there is a better place to ask this question, eg a more hardware oriented site, what would that be? Something like the equivalent of stack overflow (or perhaps a forum) for in-depth questions on hardware interfaces, internals, etc would be appreciated.

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  • Resizing image algorithm in python

    - by hippocampus
    So, I'm learning my self python by this tutorial and I'm stuck with exercise number 13 which says: Write a function to uniformly shrink or enlarge an image. Your function should take an image along with a scaling factor. To shrink the image the scale factor should be between 0 and 1 to enlarge the image the scaling factor should be greater than 1. This is not meant as a question about PIL, but to ask which algorithm to use so I can code it myself. I've found some similar questions like this, but I dunno how to translate this into python. Any help would be appreciated. I've come to this: import image win = image.ImageWin() img = image.Image("cy.png") factor = 2 W = img.getWidth() H = img.getHeight() newW = int(W*factor) newH = int(H*factor) newImage = image.EmptyImage(newW, newH) for col in range(newW): for row in range(newH): p = img.getPixel(col,row) newImage.setPixel(col*factor,row*factor,p) newImage.draw(win) win.exitonclick() I should do this in a function, but this doesn't matter right now. Arguments for function would be (image, factor). You can try it on OP tutorial in ActiveCode. It makes a stretched image with empty columns :.

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  • VTD-XML Parsing Performance (speed critical factor). Requesting Feedback/Comments

    - by andreas
    Hello, I am about to use VTD-XML (found at http://vtd-xml.sourceforge.net/) but I am interested in getting real-case usage feedback, by any one that has used the library and has any comments. At the URL (http://vtd-xml.sourceforge.net/) there are benchmarks but if someone has used VTD-XML and has comments FOR it I would like to hear them. Speed is a critical factor in the application and comments after real-case usage, by developers, is what i am looking for. Regards,

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  • Fermat factorization method limit

    - by Fakrudeen
    I am trying to implement Fermat's factorization [Algorithm C in Art of computer programming Vol. 2]. Unfortunately in my edition [ISBN 81-7758-335-2], this algorithm is printed incorrectly. what should be the condition on factor-inner loop below? I am running the loop till y <= n [passed in as limit]. (if (< limit y) 0 (factor-inner x (+ y 2) (- r y) limit)) Is there anyway to avoid this condition altogether, as it will double the speed of loop? (define (factor n) (let ( ( square-root (inexact->exact (floor (sqrt n))) ) ) (factor-inner (+ (* 2 square-root) 1) 1 (- (* square-root square-root) n) n) ) ) (define (factor-inner x y r limit) (if (= r 0) (/ (- x y) 2) (begin (display x)(display " ")(display y)(display " ")(display r)(newline) ;(sleep-current-thread 1) (if (< r 0) (factor-inner (+ x 2) y (+ r x) limit) (if (< limit y) 0 (factor-inner x (+ y 2) (- r y) limit)) ) ) ) )

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