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  • Why can't I find `len(list)` in Python?

    - by FarmBoy
    I'm new to Python. I have a method that begins: def foo(self, list): length = len(list) I've called len() successfully in other cases, but here I get: TypeError: object of type 'type' has no len() How do I convince Python that this object passed in is a list? What am I missing?

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  • How to do REST securely and with sensitive data?

    - by Earlz
    Hello, we are implementing a new web service. The web service will be a store of sensitive data and there are multiple users types with different permissions. So some user types can't access(and some can't change, and so on) certain types of data. How would this work in REST? I'm very new to REST, so sorry if this sounds noobish.

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  • Java: dangerous self-returning-recursive function by IOException?

    - by HH
    I had very errorsome Exception handling with if-clauses. An exception occurs if not found path. An exception returns the function again. The function is recursive. Safe? $ javac SubDirs.java $ java SubDirs Give me an path. . HELLO com TOASHEOU google common annotations base collect internal Give me an path. IT WON'T FIND ME, SO IT RETURNS ITSELF due to Exception caught Give me an path. $ cat SubDirs.java import java.io.*; import java.util.*; public class SubDirs { private List<File> getSubdirs(File file) throws IOException { List<File> subdirs = Arrays.asList(file.listFiles(new FileFilter() { public boolean accept(File f) { return f.isDirectory(); } })); subdirs = new ArrayList<File>(subdirs); List<File> deepSubdirs = new ArrayList<File>(); for(File subdir : subdirs) { deepSubdirs.addAll(getSubdirs(subdir)); } subdirs.addAll(deepSubdirs); return subdirs; } public static void search() { try{ BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); String s; System.out.println("Give me an path."); while ((s = in.readLine()) != null && s.length() != 0){ SubDirs dirs = new SubDirs(); List<File> subDirs = dirs.getSubdirs(new File(s)); for ( File f : subDirs ) { System.out.println(f.getName()); } System.out.println("Give me an path."); } }catch(Exception e){ // Simple but is it safe? search(); } } public static void main(String[] args) throws IOException { search(); } }

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  • Mako templates inline if statement

    - by ensnare
    I have a template variable, c.is_friend, that I would like to use to determine whether or not a class is applied. For example: if c.is_friend is True <a href="#" class="friend">link</a> if c.is_friend is False <a href="#">link</a> Is there some way to do this inline, like: <a href="#" ${if c.is_friend is True}class="friend"{/if}>link</a> Or something like that?

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  • Java: how to initialize private final int value with if-else in constructor?

    - by HH
    $ javac InitInt.java InitInt.java:7: variable right might not have been initialized InitInt(){} ^ 1 error $ cat InitInt.java import java.util.*; import java.io.*; public class InitInt { private final int right; InitInt(){} public static void main(String[] args) { // I don't want to assign any value. // just initialize it, how? InitInt test = new InitInt(); System.out.println(test.getRight()); // later assiging a value } public int getRight(){return right;} } Initialization problem with Constructor, due to if-else -loop InitInt{ // Still the error, "may not be initialized" // How to initialise it, without removing if-else? if(snippetBuilder.length()>(charwisePos+25)){ right=charwisePos+25; }else{ right=snippetBuilder.length()-1; } }

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  • Can't find ant in the Android SDK

    - by StormShadow
    Hey all, I'm working my way through APress's Beginning Android 2 and I've made it all the way to chapter 3, where we build a skeleton app. The book tells me to compile my application by typing "ant" in the command line, but my pc doesn't know what "ant" is yet. I checked in the SDK files and it looks like it wasn't included with the Android SDK. Does anybody know where ant is? Thanks

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  • Java: startingPath as "public static final" exception

    - by HH
    [Updated] Thanks to polygenelubricants's reply, the real problem is the exception from the method getCanonicalPath() because I cannot include try-catch-loop there. $ cat StartingPath.java import java.util.*; import java.io.*; public class StartingPath { public static final String startingPath = (new File(".")).getCanonicalPath(); public static void main(String[] args){ System.out.println(startingPath); } } $ javac StartingPath.java StartingPath.java:5: unreported exception java.io.IOException; must be caught or declared to be thrown public static final String startingPath = (new File(".")).getCanonicalPath(); ^ 1 error

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  • Java: define terms initialization, declaration and assignment

    - by HH
    I find the defs circular statements, the subjects are defined by their verbs but the verbs are undefined! So how do you define them? The question is central to understand the term final, related. The Circular Definitions itialization: to initilise a variable. It can be can be done at the time of declaration. assignment: to assign value to a variable. It can be done anywhere. declaration: to declare value to a variable.

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  • Java: using foreach over strings from arrayList does not print anything

    - by HH
    $ javac ArrayListTest.java $ java ArrayListTest $ cat ArrayListTest.java import java.io.*; import java.util.*; public class ArrayListTest{ public static void main(String[] args) { try { String hello ="oeoaseu oeu hsoae sthoaust hoaeut hoasntu"; ArrayList<String> appendMe = null; for(String s : hello.split(" ")) appendMe.add(s+" "); for(String s : appendMe) System.out.println(s); //WHY DOES IT NOT PRINT? }catch(Exception e){ } } }

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  • Java: why does extending need an empty constructor?

    - by HH
    I have classes SearchToUser and getFilesToWord. GetFilesToWord must inherit SearchToUser fields. Extending works if an empty construction in SearchToUser-class, otherwise: cannot find symbol symbol : constructor SearchToUser() location: class SearchToUser public class GetFilesToWord extends SearchToUser{ ^ 1 error make: *** [all] Error 1 I cannot understand why the empty constructor is required for extending.

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  • Strengths and weaknesses of JIT compilers for Python

    - by Az
    Hi there, I'm currently aware of the following Python JIT compilers: Psyco, PyPy and Unladen Swallow. Basically, I'd like to ask for your personal experiences on the strengths and weaknesses of these compilers - and if there are any others worth looking into. Thanks in advance, Az

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  • Java: custom-exception-error

    - by HH
    $ javac TestExceptions.java TestExceptions.java:11: cannot find symbol symbol : class test location: class TestExceptions throw new TestExceptions.test("If you see me, exceptions work!"); ^ 1 error Code import java.util.*; import java.io.*; public class TestExceptions { static void test(String message) throws java.lang.Error{ System.out.println(message); } public static void main(String[] args){ try { // Why does it not access TestExceptions.test-method in the class? throw new TestExceptions.test("If you see me, exceptions work!"); }catch(java.lang.Error a){ System.out.println("Working Status: " + a.getMessage() ); } } }

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  • Changing classes on multiple divs when selecting specific radio buttons

    - by Rob
    Hey everyone I got a javascript problem I can't seem to find a specific solution for on the web. What I want to be able to do is select one of the radio buttons and have that change the class of #home-right to either .rackmount or .shipping and add the class of .displaynone to the type of dimensions I don't want shown. <div id="home-right" class="rackmount"> <h4 class="helvneuebcn">Case Finder</h4> <div class="cta-options"> <input type="radio" value="Shipping and Storage" name="" checked> Shipping and Storage<br/> <input type="radio" value="Rackmount Enclosures" name=""> Rackmount Enclosures<br/> </div> <div class="shipping-dimensions displaynone"> <div class="dimensions"><input type="text" class="size"><span class="helvneuemd">H x </span></div> <div class="dimensions"><input type="text" class="size"><span class="helvneuemd">W x </span></div> <div class="dimensions"><input type="text" class="size"><span class="helvneuemd">L</span></div> </div> <div class="rackmount-dimensions"> <div class="dimensions"><input type="text" class="size"><span class="helvneuemd">U Height x </span></div> <div class="dimensions"><input type="text" class="size"><span class="helvneuemd">Rack Depth</span></div> </div> <div class="clear"></div> <input type="button" value="Submit" class="findcase"> </div>

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  • How to use infinit live streams with JAVE library? (Java, ffmpeg)

    - by Ole Jak
    So I want to use JAVE to save mp3 radio stream to my File system. I have this code for file saving but what shall I do to save a stream (stop on timer for ex) File source = new File("source.wav"); File target = new File("target.mp3"); AudioAttributes audio = new AudioAttributes(); audio.setCodec("libmp3lame"); audio.setBitRate(new Integer(128000)); audio.setChannels(new Integer(2)); audio.setSamplingRate(new Integer(44100)); EncodingAttributes attrs = new EncodingAttributes(); attrs.setFormat("mp3"); attrs.setAudioAttributes(audio); Encoder encoder = new Encoder(); encoder.encode(source, target, attrs);

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  • Python - compare nested lists and append matches to new list?

    - by Seafoid
    Hi, I wish to compare to nested lists of unequal length. I am interested only in a match between the first element of each sub list. Should a match exist, I wish to add the match to another list for subsequent transformation into a tab delimited file. Here is an example of what I am working with: x = [['1', 'a', 'b'], ['2', 'c', 'd']] y = [['1', 'z', 'x'], ['4', 'z', 'x']] match = [] def find_match(): for i in x: for j in y: if i[1] == j[1]: match.append(j) return match This results in a series of empty lists. Is it better to use tuples and/or tuples of tuples for the purposes of comparison? Any help is greatly appreciated. Regards, Seafoid.

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  • How do I create and use a junction table in Rails?

    - by Thierry Lam
    I have the following data: A post called Hello has categories greet Another post called Hola has categories greet, international My schema is: create_table "posts", :force => true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "categories", :force => true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "posts_categories", :force => true do |t| t.integer "post_id" t.integer "category_id" t.datetime "created_at" t.datetime "updated_at" end After reading the Rails guide, the most suitable relationship for the above seems to be: class Post < ActiveRecord::Base has_and_belongs_to_many :categories end class Category < ActiveRecord::Base has_and_belongs_to_many :posts end My junction table also seems to have a primary key. I think I need to get rid of it. What's the initial migration command to generate a junction table in Rails? What's the best course of action, should I drop posts_categories and re-create it or just drop the primary key column? Does the junction table have a corresponding model? I have used scaffold to generate the junction table code, should I get rid of the extra code? Assuming all the above has been fixed and is working properly, how do I query all posts and display them along with their named categories in the view. For example: Post #1 - hello, categories: greet Post #2 - hola, categories: greet, international

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  • Finding the closest grid coordinate to the mouse position with javascript/jQuery

    - by Acorn
    What I'm trying to do is make a grid of invisible coordinates on the page equally spaced. I then want a <div> to be placed at whatever grid coordinate is closest to the pointer when onclick is triggered. Here's the rough idea: I have the tracking of the mouse coordinates and the placing of the <div> worked out fine. What I'm stuck with is how to approach the problem of the grid of coordinates. First of all, should I have all my coordinates in an array which I then compare my onclick coordinate to? Or seeing as my grid coordinates follow a rule, could I do something like finding out which coordinate that is a multiple of whatever my spacing is is closest to the onclick coordinate? And then, where do I start with working out which grid point coordinate is closest? What's the best way of going about it? Thanks!

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  • Add New Gist using the Github API

    - by Ben Shelock
    I'm making a small app in Adobe Air which I need to interact with the Github Gist API. However I'm kind of stuck. If you're not familiar with Adobe Air you can still help, the XMLHttpRequest javascript object can do cross domain requests, as there is no domain as such. So theres nothing Adobe Air specific here. Where I'm stuck is I think I need to authenticate myself then make the POST. I just don't understand it

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  • How do I get an overview and a methodology for programming in Python

    - by Peter Nielsen
    I've started to learn Python and programming from scratch. I have not programmed before so it's a new experience. I do seem to grasp most of the concepts, from variables to definitions and modules. I still need to learn a lot more about what the different libraries and modules do and also I lack knowledge on OOP and classes in Python. I see people who just program in Python like that's all they have ever done and I am still just coming to grips with it. Is there a way, some tools, a logical methodology that would give me an overview or a good hold of how to handle programming problems ? For instance, I'm trying to create a parser which we need at the office . I also need to create a spider that would collect links from various websites. Is there a formidable way of studying the various modules to see what is needed ? Or is it just nose to the grind stone and understand what the documentation says ? Sorry for the lengthy question..

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  • Getting the first result from a LINQ query - why does ElementAt<T>(0) fails when First<T>() succeeds

    - by Mr Roys
    I have a method AddStudent() which looks for a student with the same name and returns an existing student from the database if there is a student with the same name, otherwise it creates a new student and adds it to the database. I'm curious why se = students.First<StudentEntity>(); succeeds when se = students.ElementAt<StudentEntity>(0); fails when I try to get the first result from the LINQ query. Aren't the two methods the same? The full code for the method is shown below. public Student AddStudent(string name) { using (SchoolEntities db = new SchoolEntities()) { // find student with same name via LINQ var students = from s in db.StudentEntitySet where s.name == name select s; StudentEntity se = default(StudentEntity); // if student with the same name is already present, return // that student if (students.Count<StudentEntity>() > 0) { // if i use ElementAt, if fails with a "LINQ to Entities does not // recognize the method 'StudentEntity ElementAt[StudentEntity] // (System.Linq.IQueryable`1[StudentEntity], Int32)' method, // and this method cannot be translated into a store expression.", // but not when I use First. Why? // se = students.ElementAt<StudentEntity>(0); se = students.First<StudentEntity>(); } else { // passing 0 for first parameter (id) since it's represented by // a BigInt IDENTITY field in the database so any value // doesn't matter. se = StudentEntity.CreateStudentEntity(0, name); db.AddToStudentEntitySet(se); db.SaveChanges(); } // create a Student object from the Entity object return new Student(se); } } Thanks!

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