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  • Proper way to set object instance variables

    - by ensnare
    I'm writing a class to insert users into a database, and before I get too far in, I just want to make sure that my OO approach is clean: class User(object): def setName(self,name): #Do sanity checks on name self._name = name def setPassword(self,password): #Check password length > 6 characters #Encrypt to md5 self._password = password def commit(self): #Commit to database >>u = User() >>u.setName('Jason Martinez') >>u.setPassword('linebreak') >>u.commit() Is this the right approach? Should I declare class variables up top? Should I use a _ in front of all the class variables to make them private? Thanks for helping out.

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  • Problem building a complete binary tree of height 'h' in Python

    - by Jack
    Here is my code. The complete binary tree has 2^k nodes at depth k. class Node: def __init__(self, data): # initializes the data members self.left = None self.right = None self.data = data root = Node(data_root) def create_complete_tree(): row = [root] for i in range(h): newrow = [] for node in row: left = Node(data1) right = Node(data2) node.left = left node.right = right newrow.append(left) newrow.append(right) row = copy.deepcopy(newrow) def traverse_tree(node): if node == None: return else: traverse_tree(node.left) print node.data traverse_tree(node.right) create_complete_tree() print 'Node traversal' traverse_tree(root) The tree traversal only gives the data of root and its children. What am I doing wrong?

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  • Windows disassembler: looking for a tool...

    - by SigTerm
    Hello. I'm looking for a (preferably free) tool that can produce "proper" disassembly listing from a (non-.NET) windows PE file (*.exe or *.dll). Important requirement: it should be possible to run the listing through a windows assembler (nasm, masm or whatever) and get working exe again (not necessarily identical to original one, but it should behave in the same way). Intended usage is adding new subroutines into existing code, when source is not available. Ideally, tool should be able to detect function/segment boundaries, API calls, and generate proper labels for jumps (I can live without labels for loops/jumps, though, but function boundary detection would be nice), and keep program resources/segments in place. I'm already aware of IdaPRO(not free), OllyDBG (useful for in-place hacking, doesn't generate disassembly listing, AFAIK), ndisasm (output isn't suitable for assembler), dumpbin (useful, but AFAIK, output isn't suitable for assembler) and "proxy dll" technique. Ideas? Or maybe there is a book/tutorial that explains some kind of alternative approach?

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  • return new string vs .ToString()

    - by Leroy Jenkins
    Take the following code: public static string ReverseIt(string myString) { char[] foo = myString.ToCharArray(); Array.Reverse(foo); return new string(foo); } I understand that strings are immutable, but what I dont understand is why a new string needs to be called return new string(foo); instead of return foo.ToString(); I have to assume it has something to do with reassembling the CharArray (but thats just a guess). Whats the difference between the two and how do you know when to return a new string as opposed to returning a System.String that represents the current object?

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  • Map only certain parts of the class to a database using SQLAlchemy?

    - by Az
    When mapping an object using SQLAlchemy, is there a way to only map certain elements of a class to a database, or does it have to be a 1:1 mapping? Example: class User(object): def __init__(self, name, username, password, year_of_birth): self.name = name self.username = username self.password = password self.year_of_birth = year_of_birth Say, for whatever reason, I only wish to map the name, username and password to the database and leave out the year_of_birth. Is that possible and will this create problems? Edit - 25/03/2010 Additionally, say I want to map username and year_of_birth to a separate database. Will this database and the one above still be connected (via username)?

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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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  • java source code doubt

    - by abson
    this compiles class ex1 { public int show() { try { int a=10/10; return 10;} catch(ArithmeticException e) { System.out.println(e); } finally { System.out.println("Finally");} System.out.println("hello"); return 20; } } on the other hand this doesn't class ex15 { public int show() { try { int a=10/0; return 10;} catch(ArithmeticException e) { System.out.println(e); } finally { System.out.println("Finally"); return 40;} System.out.println("hello"); return 20; } } why is it so?

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  • What is ADO.NET?

    - by ChrisC
    I've written a few Access db's and used some light VBA, and had an OO class. Now I'm undertaking to write a C# db app. I've got VS and System.Data.SQLite installed and connected, and have entered my tables and columns, but that's where I'm stuck. I'm trying to find what info and tutorials I need to look for, but there are a lot of terms I don't understand and I don't know if or exactly how they apply to my project. I've read definitions for these terms (Wikipedia and elsewhere), but the definitions don't make sense to me because I don't know what they are or how they fit together or which ones are optional or not optional for my project. Some of the terms on the System.Data.SQLite website (I wanted to use System.Data.SQLite for my db). I figured my first step in my project would be to get the db and queries set up and tested. Please tell me if there are other pieces of this part of the puzzle I will need to know about, too. If I can figure out what's what, I can start looking for the tutorials I need. (btw, I know I don't want to use an ORM because my app is so simple, and because I want to keep from biting off too much too soon.) Thank you very much. SQLite.NET ADO.NET ADO.NET provider ADO.NET 2.0 Provider for SQLite SQLite Entity Framework SQLite Entity Framework provider

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  • How do I edit a row in NSTableView to allow deleting the data in that row and replacing with new d

    - by lampShade
    I'm building a to-do-list application and I want to be able to edit the entries in the table and replace them with new entries. I'm close to being able to do what I want but not quit. Here is my code so far: /* IBOutlet NSTextField *textField; IBOutlet NSTabView *tableView; IBOutlet NSButton *button; NSMutableArray *myArray; */ #import "AppController.h" @implementation AppController -(IBAction)addNewItem:(id)sender { [myArray addObject:[textField stringValue]]; [tableView reloadData]; } - (int)numberOfRowsInTableView:(NSTableView *)aTableView { return [myArray count]; } - (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(int)rowIndex { return [myArray objectAtIndex:rowIndex]; } - (id)init { [super init]; myArray = [[NSMutableArray alloc] init]; return self; } -(IBAction)removeItem:(id)sender { NSLog(@"This is the index of the selected row: %d",[tableView selectedRow]); NSLog(@"the clicked row is %d",[tableView clickedRow]); [myArray replaceObjectAtIndex:[tableView selectedRow] withObject:[textField stringValue]]; [myArray addObject:[textField stringValue]]; //[tableView reloadData]; } @end

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  • how to bind the click event of a button and the selecteditemchanged of a listbox to a viewmodel in m

    - by Michel
    Hi, i'm just starting with the mvvm model in Silverlight. In step 1 i got a listbox bound to my viewmodel, but now i want to propagate a click in a button and a selecteditemchanged of the listbox back to the viewmodel. I guess i have to bind the click event of the button and the selecteditemchanged of the listbox to 2 methods in my viewmodel somehow? For the selecteditemchanged of the listbox i think there must also be a 'return call' possible when the viewmodel tries to set the selecteditem to another value? i come from a asp.net (mvc) background, but can't figure out how to do it in silverlight.

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  • Simple non-network concurrency with Twisted

    - by Rince
    Dear pythoners, I have a problem with using Twisted for simple concurrency in python. The problem is - I don't know how to do it and all online resources are about Twisted networking abilities. So I am turning to SO-gurus for some guidance. Python 2.5 is used. Simplified version of my problem runs as follows: A bunch of scientific data A function that munches on the data and creates output ??? < here enters concurrency, it takes chunks of data from 1 and feeds it to 2 Output from 3 is joined and stored My guess is that Twisted reactor can do the number three job. But how? Thanks a lot for any help and suggestions.

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  • Books recommendation to learn about java networking

    - by elec
    In order to cover for my (glaring) lack of knowledge in the basics of networking, I'm looking for a book which would ideally cover: - 1 or 2 chapters on the transport layer: tcp, udp... - 1 or 2 chapters on the application layer: http, dns... - rest of the book would be devoted to pratical way of sending data across the wire using Java-related technologies. This would involve discussions about existing products (eg. hessian, protobuf, thrift, tibco...) , performances comparisons, case studies...etc.. Does such a book exist ?

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  • Spaces while using "Print" in VBA

    - by Josh
    For some reason I am getting a lot of spaces in front of each value while trying to print to a flat text file. 'append headers Cells(start_row - 2, 1).Select For i = 1 To ActiveCell.SpecialCells(xlLastCell).Column If ActiveCell.Offset(0, 1).Column = ActiveCell.SpecialCells(xlLastCell).Column Then Print #finalCSV, Cells(start_row - 2, i) & "\n", Else Print #finalCSV, Cells(start_row - 2, i) & ",", End If Next i Example output: DC Capacity:hi, Resistive Capacity:lo, Resistive Capacity:hi, Reactive Capacity:lo, Is there any way to get rid of these spaces?

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  • Odd nested dictionary behavior in python

    - by adept
    Im new two python and am trying to grow a dictionary of dictionaries. I have done this in php and perl but python is behaving very differently. Im sure it makes sense to those more familiar with python. Here is my code: colnames = ['name','dob','id']; tablehashcopy = {}; tablehashcopy = dict.fromkeys(colnames,{}); tablehashcopy['name']['hi'] = 0; print(tablehashcopy); Output: {'dob': {'hi': 0}, 'name': {'hi': 0}, 'id': {'hi': 0}} The problem arises from the 2nd to last statement(i put the print in for convenience). I expected to find that one element has been added to the 'name' dictionary with the key 'hi' and the value 0. But this key,value pair has been added to EVERY sub-dictionary. Why? I have tested this on my ubuntu machine in both python 2.6 and python 3.1 the behaviour is the same.

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  • Simple PHP file

    - by Peter
    Here is my code <html> <body> <?php echo "<b>Hello World</b> <br />"; ?> </body> </html> I have named the file as test.php but I dont get the desired output in my firefox 3.6 browser. Output Hello World "; ?>

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  • GoTo statements, and alternatives (help me please im new) (VB.net)

    - by qais
    Basically I posted a code snippet on a forum asking for help and people pointed out to me that using GoTo statements is very bad programming practise so I'm just wondering, why is it bad? And also what alternative is there to use, like for example in this program ive done for homework the user has to input their date of birth and if the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if theres any better way to do this i'd appreciate if you could tell me that also :D) then how would i be able to loop back to ask them again? heres a little extract of my code retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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  • What are the basics of dealing with user input events in Android?

    - by user279112
    Hello. I thought I had understood this question, but something is quite wrong here. When the user (me, so far) tries to press keys, nothing really happens, and I am having a lot of trouble understanding what it is that I've missed. Consider this before I present some code to help clarify my problem: I am using Android's Lunar Lander example to make my first "real" Android program. In that example, of course, there exist a class LunarView, and class nested therein LunarThread. In my code the equivalents of these classes are Graphics and GraphicsThread, respectively. Also I can make sprite animations in 2D just fine on Android. I have a Player class, and let's say GraphicsThread has a Player member referred to as "player". This class has four coordinates - x1, y1, x2, and y2 - and they define a rectangle in which the sprite is to be drawn. I've worked it out so that I can handle that perfectly. Whenever the doDraw(Canvas canvas) method is invoked, it'll just look at the values of those coordinates and draw the sprite accordingly. Now let's say - and this isn't really what I'm trying to do with the program - I'm trying to make the program where all it does is display the Player sprite at one location of the screen UNTIL the FIRST time the user presses the Dpad's left button. Then the location will be changed to another set position on the screen, and the sprite will be drawn at that position for the rest of the program invariably. Also note that the GraphicsThread member in Graphics is called "thread", and that the SurfaceHolder member in GraphicsThread is called "mSurfaceHolder". So consider this method in class Graphics: @Override public boolean onKeyDown(int keyCode, KeyEvent msg) { return thread.keyDownHandler(keyCode, msg); } Also please consider this method in class GraphicsThread: boolean keyDownHandler(int keyCode, KeyEvent msg) { synchronized (mSurfaceHolder) { if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT) { player.x1 = 100; player.y1 = 100; player.x2 = 120; player.y2 = 150; } } return true; } Now then assuming that player's coordinates start off as (200, 200, 220, 250), why won't he do anything different when I press Dpad: Left? Thanks!

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  • I can't set a border around my StackPanel. Any help?

    - by Sergio Tapia
    Here's my XAML code: <Window x:Class="CarFinder.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Search for cars in TuMomo" Height="480" Width="600"> <DockPanel Margin="8"> <Border CornerRadius="6" BorderBrush="Gray" Background="LightGray" BorderThickness="2" Padding="8"> <StackPanel Orientation="Horizontal" DockPanel.Dock="Top" Height="25"> <TextBlock FontSize="14" Padding="0 0 8 0"> Search: </TextBlock> <TextBox x:Name="txtSearchTerm" Width="400" /> <Image Source="/CarFinder;component/Images/Chrysanthemum.jpg" /> </StackPanel> </Border> <StackPanel Orientation="Horizontal" DockPanel.Dock="Top" Height="25"> </StackPanel> </DockPanel> </Window> The border is set around the entire window. And also, when I create another StackPanel it's added to the right of my previous StackPanel instead of being added under it. What's the reason for this?

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  • VB.net Cross-Thread

    - by PandaNL
    Hello, I have a cmd command that needs to be executed, when the command starts it starts to fill a progressbar. When the cmd command is done the progressbar needs to fill up to 100. This is the code i use, but it gives me an error when the progressbar.Value = 100 comes up. Public Class Form1 Dim teller As Integer Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TimerProgressbar.Tick teller += 1 ProgressBar1.Value = teller If ProgressBar1.Value = ProgressBar1.Maximum Then TimerProgressbar.Stop() End If End Sub This are the tow commands in another private sub where the app is crashing on ProgressBar1.Value = 100 TimerProgressbar.Stop() When i debug it and i try it out it crashes on ProgressBar1.Value = 100 But when i build it under Windows 7 it runs fine without crashing, however a few people reported me it crashes on there Windows xp system. VB gives me a suggestions about Cross Thread, but i don't know how i could make it work with this.

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  • How to learn about Threads, Especially in Java.

    - by Javed Ahamed
    I have always been kind of confused by threads, and my class right now makes heavy use of them. We are using java.util.concurrent but I don't even really get the basics. UpDownLatch, Futures, Executors; these words just fly over my head. Can you guys suggest any resources to help learn what I need from the ground up? Thanks a lot in advance!

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