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  • Running iPython from the OSX terminal.

    - by Az
    So I'm going through the matplotlib documentation and prepared to use the iPython interactive Python shell with ipython -pylab. However I get this: Az's MBP:~ Az$ ipython -pylab -bash: ipython: command not found Did I fail to install iPython? I used easy_install as advised. Any ideas?

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  • Initialize a Variable Again.

    - by SoulBeaver
    That may sound a little confusing. Basically, I have a function CCard newCard() { /* Used to store the string variables intermittantly */ std::stringstream ssPIN, ssBN; int picker1, picker2; int pin, bankNum; /* Choose 5 random variables, store them in stream */ for( int loop = 0; loop < 5; ++loop ) { picker1 = rand() % 8 + 1; picker2 = rand() % 8 + 1; ssPIN << picker1; ssBN << picker2; } /* Convert them */ ssPIN >> pin; ssBN >> bankNum; CCard card( pin, bankNum ); return card; } that creates a new CCard variable and returns it to the caller CCard card = newCard(); My teacher advised me that doing this is a violation of OOP principles and has to be put in the class. He told me to use this method as a constructor. Which I did: CCard::CCard() { m_Sperre = false; m_Guthaben = rand() % 1000; /* Work */ /* Convert them */ ssPIN >> m_Geheimzahl; ssBN >> m_Nummer; } All variables with m_ are member variables. However, the constructor works when I initialize the card normally CCard card(); at the start of the program. However, I also have a function, that is supposed to create a new card and return it to the user, this function is now broken. The original command: card = newCard(); isn't available anymore, and card = new CCard(); doesn't work. What other options do I have? I have a feeling using the constructor won't work, and that I probably should just create a class method newCard, but I want to see if it is somehow at all possible to do it the way the teacher wanted. This is creating a lot of headaches for me. I told the teacher that this is a stupid idea and not everything has to be classed in OOP. He has since told me that Java or C# don't allow code outside of classes, which sounds a little incredible. Not sure that you can do this in C++, especially when templated functions exist, or generic algorithms. Is it true that this would be bad code for OOP in C++ if I didn't force it into a class?

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  • Is using the break statement bad practice?

    - by Lchi
    I've been told by professors and peers at my university that using the break statement is bad practice, but through my coursework haven't come up with a great reason why. Those who claim that it is bad say that it's a "get out of jail free card" and that you can always avoid using it. My guesses for why its considered bad would be that you could possibly skip some cleanup code after the break, or similarly exit some control structure in an inconsistent state. Is there any reason why using break is(n't) bad practice?

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  • Problem with for-loop in python

    - by Protean
    This code is supposed to be able to sort the items in self.array based upon the order of the characters in self.order. The method sort runs properly until the third iteration, unil for some reason the for loop seems to repeat indefinitely. What is going on here? class sorting_class: def __init__(self): self.array = ['ca', 'bd', 'ac', 'ab'] #An array of strings self.arrayt = [] self.globali = 0 self.globalii = 0 self.order = ['a', 'b', 'c', 'd'] #Order of characters self.orderi = 0 self.carry = [] self.leave = [] self.sortedlist = [] def sort(self): for arrayi in self.arrayt: #This should only loop for the number items in self.arrayt. However, the third time this is run it seems to loop indefinitely. print ('run', arrayi) #Shows the problem if self.order[self.orderi] == arrayi[self.globali]: self.carry.append(arrayi) else: if self.globali != 0: self.leave.append(arrayi) def srt(self): self.arrayt = self.array my.sort() #First this runs the first time. while len(self.sortedlist) != len(self.array): if len(self.carry) == 1: self.sortedlist.append(self.carry) self.arrayt = self.leave self.leave = [] self.carry = [] self.globali = 1 self.orderi = 0 my.sort() elif len(self.carry) == 0: if len(self.leave) != 0: #Because nothing matches 'aa' during the second iteration, this code runs the third time" self.arrayt = self.leave self.globali = 1 self.orderi += 1 my.sort() else: self.arrayt = self.array self.globalii += 1 self.orderi = self.globalii self.globali = 0 my.sort() self.orderi = 0 else: #This is what runs the second time. self.arrayt = self.carry self.carry = [] self.globali += 1 my.sort() my = sorting_class() my.srt()

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  • Getting unpredictable data into a tabular format

    - by Acorn
    The situation: Each page I scrape has <input> elements with a title= and a value= I don't know what is going to be on the page. I want to have all my collected data in a single table at the end, with a column for each title. So basically, I need each row of data to line up with all the others, and if a row doesn't have a certain element, then it should be blank (but there must be something there to keep the alignment). eg. First page has: {animal: cat, colour: blue, fruit: lemon, day: monday} Second page has: {animal: fish, colour: green, day: saturday} Third page has: {animal: dog, number: 10, colour: yellow, fruit: mango, day: tuesday} Then my resulting table should be: animal | number | colour | fruit | day cat | none | blue | lemon | monday fish | none | green | none | saturday dog | 10 | yellow | mango | tuesday Although it would be good to keep the order of the title value pairs, which I know dictionaries wont do. So basically, I need to generate columns from all the titles (kept in order but somehow merged together) What would be the best way of going about this without knowing all the possible titles and explicitly specifying an order for the values to be put in?

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  • How to use SQLite3 with Java

    - by Bruce
    I am trying to build a simple java program which creates a db file, then a table and inserts dummy values in the table. I found this page http://www.zentus.com/sqlitejdbc/index.html and tried out the example given on the page but I am getting the following error - Exception in thread "main" java.lang.NoClassDefFoundError: Test Caused by: java.lang.ClassNotFoundException: Test at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) Could not find the main class: Test. Program will exit.

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  • Efficiently generate a 16-character, alphanumeric string

    - by ensnare
    I'm looking for a very quick way to generate an alphanumeric unique id for a primary key in a table. Would something like this work? def genKey(): hash = hashlib.md5(RANDOM_NUMBER).digest().encode("base64") alnum_hash = re.sub(r'[^a-zA-Z0-9]', "", hash) return alnum_hash[:16] What would be a good way to generate random numbers? If I base it on microtime, I have to account for the possibility of several calls of genKey() at the same time from different instances. Or is there a better way to do all this? Thanks.

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  • Difference in Django object creation call

    - by PhilGo20
    I'd like to know if there's a difference between the following two calls to create an object in Django Animal.objects.create(name="cat", sound="meow") and Animal(name="cat", sound="meow") I see both in test cases and I want to make sure I am not missing something. thanks

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  • How to share a variable between two classes?

    - by Altefquatre
    How would you share the same object between two other objects? For instance, I'd like something in that flavor: class A { private string foo_; // It could be any other class/struct too (Vector3, Matrix...) public A (string shared) { this.foo_ = shared; } public void Bar() { this.foo_ = "changed"; } } ... // inside main string str = "test"; A a = new A(str); Console.WriteLine(str); // "test" a.Bar(); Console.WriteLine(str); // I get "test" instead of "changed"... :( I read there is some ref/out stuff, but I couldn't get what I'm asking here. I could only apply some changes in the methods scope where I was using ref/out arguments... I also read we could use pointers, but is there no other way to do it?

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  • Formula to follow addition of rows

    - by Wayne McCaslin
    New to VBA, please help. I have a range say A2:D10; input causes rows to be added. New entries are being added using NextRow=_. Works perfectly, however, how do I get the formulas in columns C and D to follow each new row being added. I cannot just format entire column due to my sort criteria. Example formula is =IF(ISTEXT($B11),$C$2-$D11,"")

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  • diff between tables

    - by www.yegorov-p.ru
    I have two tables, with the same structure, for example: table "first' with columns 'a','b','c' and table 'second' with the same columns. How to find difference betweet those two tables? Of course, I can make some script on python, that will make set(a)-set(b), but I think there is some way to do it in mysql.

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  • Restore previously serialized JFrame-object, how?

    - by elementz
    Hi all. I have managed to serialize my very basic GUI-object containing a JTextArea and a few buttons to a file 'test.ser'. Now, I would like to completely restore the previously saved state from 'test.ser', but seem to have a misconception of how to properly deserialize an objects state. The class MyFrame creates the JFrame and serializes it. public class MyFrame extends JFrame implements ActionListener { // Fields JTextArea textArea; String title; static MyFrame gui = new MyFrame(); private static final long serialVersionUID = 1125762532137824262L; /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub gui.run(); } // parameterless default contructor public MyFrame() { } // constructor with title public MyFrame(String title) { } // creates Frame and its Layout public void run() { JFrame frame = new JFrame(title); JPanel panel_01 = new JPanel(); JPanel panel_02 = new JPanel(); JTextArea textArea = new JTextArea(20, 22); textArea.setLineWrap(true); JScrollPane scrollPane = new JScrollPane(textArea); scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED); panel_01.add(scrollPane); // Buttons JButton saveButton = new JButton("Save"); saveButton.addActionListener(this); JButton loadButton = new JButton("Load"); loadButton.addActionListener(this); panel_02.add(loadButton); panel_02.add(saveButton); // Layout frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(BorderLayout.CENTER, panel_01); frame.getContentPane().add(BorderLayout.SOUTH, panel_02); frame.setSize(300, 400); frame.setVisible(true); } /* * */ public void serialize() { try { ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test.ser")); oos.writeObject(gui); oos.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } } public void actionPerformed(ActionEvent ev) { System.out.println("Action received!"); gui.serialize(); } } Here I try to do the deserialization: public class Deserialize { static Deserialize ds; static MyFrame frame; public static void main(String[] args) { try { ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.ser")); frame = (MyFrame) ois.readObject(); ois.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } Maybe somebody could point me into the direction where my misconception is? Thx in advance!

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  • creation of folders in python

    - by beena shamsudeen
    i want to create folders with the name of a pdf file for eg,abc.if it does not exists,i should create a folder with name abc_1...if abc_1 exists,i shud create abc_2.if both exxists,abc_3 and so on...the scripting is in python..can u help me??

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  • Why do I get "mysql_query(): supplied argument is not a valid"

    - by Brian Ojeda
    Why do I get a "mysql_query(): supplied argument is not a valid" for the first... $r = mysql_query($q, $connection); In the following code... $bId = trim($_POST['bId']); $title = trim($_POST['title']); $story = trim($_POST['story']); $q = "SELECT * "; $q .= "FROM " . DB_NAME . ".`blog` "; $q .= "WHERE `blog`.`id` = {$bId}"; $r = mysql_query($q, $connection); //confirm_query($r); if (mysql_num_rows($r) == 1) { $q = "UPDATE " . DB_NAME . ".`blog` SET `title` = '{$title}', `story` = '{$story}' WHERE `id` = {$bId}"; $r = mysql_query($q, $connection); if (mysql_affected_rows() == 1) { //Successful $data['success'] = true; $date['errors'] = false; $date['message'] = "You are the Greatest!"; } else { //Fail $data['success'] = false; $data['error'] = true; $date['message'] = "You can't do it fool!"; } } I also get an "mysql_num_rows(): supplied argument is not a valid MySQL result resource" error too. Side notes: I am using 1&1 Hosting (worst hosting ever), custom .htaccess file with one line text to enable PHP 5.2 (only why with 1&1 Hosting).

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  • Network Security and Encryption explained in laymen terms

    - by Ehrann Mehdan
    Although I might pretend very well that I known a thing about networks or security and it might help me pass an interview, or fix a bug, I don't really feel I'm fooling anyone. I'm looking for a laymen terms explanation of nowadays network security concepts and solutions. The information is scattered around and I didn't find a resource for "dummies" like me (e.g experienced Java developers that can speak the jargon but have no real clue what it means) Topics I have a weak notion about and want to understand better as a Java developer PGP Public / Private keys RSA / DES SSL and 2 way SSL (keystore / trustore) Protecting against Man in the middle fraud Digital Signature and Certificates Is there a resource out there that really explains it in a way that doesn't require a Cisco certificate / Linux lingo / know what is subnet masking or other plumbing skills?

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  • Getting started with microcontroller programming

    - by Trix
    I'm a fairly good programmer, knowledgeable in C, C++, Python, Ruby and PHP. I'd like to get started with microcontroller programming. I do know nothing about this topic. Microcontrollers are minimal computers on little circuit boards, right? I'm pretty new to electronics too, do I need to be an expert in it to do stuff with microcontrollers? What can I do with them? Would e.g.: A Pacman or Tetris game on an LCD be possible and not too hard? Where should I start? Basically I want to program something really small I can then take with me. This is my only real goal. Are microcontrollers the right thing for this, or are there better solutions? I'd like to do this for fun and as a hobby, I don't want to become a professional in it.

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  • [Delphi] How would you refactor this code?

    - by Al C
    This hypothetical example illustrates several problems I can't seem to get past, even though I keep trying!! ... Suppose the original code is a long event handler, coded in the UI, triggered when a user clicks a cell in a grid. Expressed as pseudocode it's: if Condition1=true then begin //loop through every cell in row, //if aCell/headerCellValue>1 then //color aCell red end else if Condition2=true then begin //do some other calculation adding cell and headerCell values, and //if some other product>2 then //color the whole row green end else show an error message I look at this and say "Ah, refactor to the strategy pattern! The code will be easier to understand, easier to debug, and easier to later extend!" I get that. And I can easily break the code into multiple procedures. The problem is ultimately scope related. Assume the pseudocode makes extensive use of grid properties, values displayed in cells, maybe even built-in grid methods. How do you move all that to another unit, without referencing the grid component in the UI--which would break all the "rules" about loose coupling that make OOP valuable? ... I'm really looking forward to responses. Thanks, as always -- Al C.

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  • importing class and its function from another file

    - by user343934
    Hi everyone, I am having little problem with importing classes in python. My work flow goes like this index.py class Template: def header(): def body(): def form(): def footer(): display.py I want to call function header(), body() and footer () in my display.py page. Will anyone make me clear about this issue in python. Thanks for your concern.

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  • Exception error in Erlang

    - by Jim
    So I've been using Erlang for the last eight hours, and I've spent two of those banging my head against the keyboard trying to figure out the exception error my console keeps returning. I'm writing a dice program to learn erlang. I want it to be able to call from the console through the erlang interpreter. The program accepts a number of dice, and is supposed to generate a list of values. Each value is supposed to be between one and six. I won't bore you with the dozens of individual micro-changes I made to try and fix the problem (random engineering) but I'll post my code and the error. The Source: -module(dice2). -export([d6/1]). d6(1) - random:uniform(6); d6(Numdice) - Result = [], d6(Numdice, [Result]). d6(0, [Finalresult]) - {ok, [Finalresult]}; d6(Numdice, [Result]) - d6(Numdice - 1, [random:uniform(6) | Result]). When I run the program from my console like so... dice2:d6(1). ...I get a random number between one and six like expected. However when I run the same function with any number higher than one as an argument I get the following exception... **exception error: no function clause matching dice2:d6(1, [4|3]) ... I know I I don't have a function with matching arguments but I don't know how to write a function with variable arguments, and a variable number of arguments. I tried modifying the function in question like so.... d6(Numdice, [Result]) - Newresult = [random:uniform(6) | Result], d6(Numdice - 1, Newresult). ... but I got essentially the same error. Anyone know what is going on here?

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