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  • How do I set up my @product=Product.find(params[:id]) to have a product_url?

    - by montooner
    Trying to recreate { script/generate scaffold }, and I've gotten thru a number of Rails basics. I suspect that I need to configure default product url somewhere. But where do I do this? Setup: Have: def edit { @product=Product.find(params[:id]) } Have edit.html.erb, with an edit form posting to action = :create Have def create { ... }, with the code redirect_to(@product, ...) Getting error: undefined method `product_url' for #< ProductsController:0x56102b0 My def update: def update @product = Product.find(params[:id]) respond_to do |format| if @product.update_attributes(params[:product]) format.html { redirect_to(@product, :notice => 'Product was successfully updated.') } format.xml { head :ok } else format.html { render :action => "edit" } format.xml { render :xml => @product.errors, :status => :unprocessable_entity } end end end

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  • GoTo statements and alternatives in VB.NET

    - by qais
    I've posted a code snippet on another forum asking for help and people pointed out to me that using GoTo statements is very bad programming practice. I'm wondering: why is it bad? What alternatives to GoTo are there to use in VB.NET that would be considered generally more of a better practice? Consider this snippet below where the user has to input their date of birth. If the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if there's a better way to do this, I'd appreciate if you could tell me that also :D) How would I be able to loop back to ask the user again? 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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  • python: equivalent to Javascript "||" to override non-truthful value

    - by Jason S
    In Javascript I can do this: function A(x) { return x || 3; } This returns 3 if x is a "non-truthful" value like 0, null, false, and it returns x otherwise. This is useful for empty arguments, e.g. I can do A() and it will evaluate as 3. Does Python have an equivalent? I guess I could make one out of the ternary operator a if b else c but was wondering what people use for this.

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  • An old flaw in X Window System. How does it work?

    - by Legend
    I was going through an article today when it mentioned the following: "We've found many errors over the years. One of the absolute best was the following in the X Window System: if(getuid() != 0 && geteuid == 0) { ErrorF("Only root"); exit(1); } It allowed any local user to get root access. (The tautological check geteuid == 0 was intended to be geteuid() == 0. In its current form, it compress the address of geteuid to 0; given that the function exists, its address is never 0)." The article explained what was wrong with the code but I would like to know what it means to say that "It allowed any local user to get root access". I am not an expert in C but can someone give me an exact context in which this exploit would work? Specifically, what I mean is, lets say I am the local user, how would I get root access if we assume this code to be present somewhere?

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  • Dynamically calling functions - Python

    - by RadiantHex
    Hi folks, I have a list of functions... e.g. def filter_bunnies(pets): ... def filter_turtles(pets): ... def filter_narwhals(pets): ... Is there a way to call these functions by using a string representing their name? e.g. 'filter_bunnies', 'filter_turtles', 'filter_narwhals'

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  • How to make if-elif-else statement in python more space-saving?

    - by Neverland
    I have a lot of if-elif-else statements in my code if message == '0' or message == '3' or message == '5' or message == '7': ... elif message == '1' or message == '2' or message == '4' or message == '6' or message == '8': ... else: ... Is it possible to format this in a more space-saving way? I tried it this way: if message == '0' or '3' or '5' or '7': ... elif message == '1' or '2' or '4' or '6' or '8': ... else: ... But without success.

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  • When I overload the assignment operator for my simple class array, I get the wrong answer I espect

    - by user299648
    //output is "01234 00000" but the output should be or what I want it to be is // "01234 01234" because of the assignment overloaded operator #include <iostream> using namespace std; class IntArray { public: IntArray() : size(10), used(0) { a= new int[10]; } IntArray(int s) : size(s), used(0) { a= new int[s]; } int& operator[]( int index ); IntArray& operator =( const IntArray& rightside ); ~IntArray() { delete [] a; } private: int *a; int size; int used;//for array position }; int main() { IntArray copy; if( 2>1) { IntArray arr(5); for( int k=0; k<5; k++) arr[k]=k; copy = arr; for( int j=0; j<5; j++) cout<<arr[j]; } cout<<" "; for( int j=0; j<5; j++) cout<<copy[j]; return 0; } int& IntArray::operator[]( int index ) { if( index >= size ) cout<<"ilegal index in IntArray"<<endl; return a[index]; } IntArray& IntArray::operator =( const IntArray& rightside ) { if( size != rightside.size )//also checks if on both side same object { delete [] a; a= new int[rightside.size]; } size=rightside.size; used=rightside.used; for( int i = 0; i < used; i++ ) a[i]=rightside.a[i]; return *this; }

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  • C Array of string

    - by Meko
    HI. This is maybe simple question but I want to create two dimensional array and add it string like in java string str = "text" ; string [][] array = new [][] string ; array[i][j] = str ; But in C there is no string .I tried like this but here strcpy() gives error.It returns to assembly code. I am trying to read line by line from text and split line by space and add them to structure.But first I think that I must add each line and row in array and then making iteration and adding to structures fields. static const char filename[] = "student.txt"; FILE *file = fopen ( filename, "r" ); char line [ 128 ]; /* or other suitable maximum line size */ char delims [ ]=" "; char *result =NULL; char list[15]; char arra[128][128]; int i=0; int j=0; struct { char gruppa[10]; char familiya[20]; int uchaste; struct { int firsth; int second; int third; int fourht; int fifth; } exam; }student; for(i=0; i<128; i++) for(j=0; j<128; j++) arra[i][j] = '\0'; for(i=0; i<15; i++) list[i] = '\0'; if ( file != NULL ) { while ( fgets ( line, sizeof line, file ) != NULL ) { result = strtok(line,delims); while (result !=NULL) { strcpy(list,("%s",result)); strcpy(arra[i][j],list); // Here it gives errror j++; result = strtok(NULL,delims); } j=0; i++; } fclose ( file ); } else { perror ( filename ); } getchar(); return 0; }

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  • Declaring an integer Range with step != 1 in Ruby

    - by Dan Tao
    Hey guys, I'm completely new to Ruby, so be gentle. Say I want to iterate over the range of even numbers from 2 to 100; how would I do that? Obviously I could do: (2..100).each do |x| if x % 2 == 0 # my code end end But, obviously (again), that would be pretty stupid. I know I could do something like: i = 2 while i <= 100 # my code i += 2 end I believe I could also write my own custom class that provides its own each method (?). I am almost sure that would be overkill, though. I'm interested in two things: Is it possible to do this with some variation of the standard Range syntax (i.e., (x..y).each)? Either way, what would be the most idiomatic "Ruby way" of accomplishing this (using a Range or otherwise)? Like I said, I'm new to the language; so any guidance you can offer on how to do things in a more typical Ruby style would be much appreciated.

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  • Drupal - Generating forms from the database.

    - by YsoL8
    Hello I'm trying to teach myself Drupal and I've found something I can't find any tutorials for. I am trying to generate a form, with a dynamic number of text fields, to populate and edit the contents of my custom table. In regular PHP I would achieve this with: $count = '0'; while ($row = mysql_fetch_array ($result) { echo "<input type='text' name='title_row".$count."' value='".$row['title']."'>" $count = $count +1; } Can someone point me to something that'll show me how to do that in Drupal (and processing the submited data)? Thanks

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  • MySQL::Eliminating redundant elements from a table?

    - by Legend
    I have a table like this: +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | v1 | int(11) | YES | MUL | NULL | | | v2 | int(11) | YES | MUL | NULL | | +-------+---------+------+-----+---------+-------+ There is a tremendous amount of duplication in this table. For instance, elements like the following: +------+------+ | v1 | v2 | +------+------+ | 1 | 2 | | 1 | 3 | | 1 | 4 | | 1 | 5 | | 1 | 6 | | 1 | 7 | | 1 | 8 | | 1 | 9 | | 2 | 1 | | 4 | 1 | | 5 | 1 | | 6 | 1 | | 7 | 1 | | 8 | 1 | | 9 | 1 | +------+------+ The table is large with 1540000 entries. To remove the redundant entries (i.e. to get a table having only (1,9) and no (9,1) entries), I was thinking of doing it with a subquery but is there a better way of doing this?

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  • Java Graphics not displaying on successive function calls, why?

    - by primehunter326
    Hi, I'm making a visualization for a BST implementation (I posted another question about it the other day). I've created a GUI which displays the viewing area and buttons. I've added code to the BST implementation to recursively traverse the tree, the function takes in coordinates along with the Graphics object which are initially passed in by the main GUI class. My idea was that I'd just have this function re-draw the tree after every update (add, delete, etc...), drawing a rectangle over everything first to "refresh" the viewing area. This also means I could alter the BST implementation (i.e by adding a balance operation) and it wouldn't affect the visualization. The issue I'm having is that the draw function only works the first time it is called, after that it doesn't display anything. I guess I don't fully understand how the Graphics object works since it doesn't behave the way I'd expect it to when getting passed/called from different functions. I know the getGraphics function has something to do with it. Relevant code: private void draw(){ Graphics g = vPanel.getGraphics(); tree.drawTree(g,ORIGIN,ORIGIN); } vPanel is what I'm drawing on private void drawTree(Graphics g, BinaryNode<AnyType> n, int x, int y){ if( n != null ){ drawTree(g, n.left, x-10,y+10 ); if(n.selected){ g.setColor(Color.blue); } else{ g.setColor(Color.gray); } g.fillOval(x,y,20,20); g.setColor(Color.black); g.drawString(n.element.toString(),x,y); drawTree(g,n.right, x+10,y+10); } } It is passed the root node when it is called by the public function. Do I have to have: Graphics g = vPanel.getGraphics(); ...within the drawTree function? This doesn't make sense!! Thanks for your help.

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  • List in a Python class shares the same object over 2 different instances?

    - by zfranciscus
    I created a class: class A: aList = [] now I have function that instantiate this class and add items into the aList. note: there are 2 items for item in items: a = A(); a.aList.append(item); I find that the first A and the second A object has the same number of items in their aList. I would expect that the first A object will have the first item in its list and the second A object will have the second item in its aList. Can anyone explain how this happens ? PS: I manage to solve this problem by moving the aList inside a constructor : def __init__(self): self.aList = []; but I am still curious about this behavior

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  • Unix: cannot add "\\ \n" even with escaping to the end of line

    - by HH
    I try to convert clean columnwise data to tables in tex. I am unable to have "\ \n" at each end of line. Please, see the command at the end. Data $ echo `. ./bin/addTableTexTags.sh < .data_3` 10.31 & 8.50 & 7.40 10.34 & 8.53 & 7.81 8.22 & 8.62 & 7.78 10.16 & 8.53 & 7.44 10.41 & 8.38 & 7.63 10.38 & 8.57 & 8.03 10.13 & 8.66 & 7.41 8.50 & 8.60 & 7.15 10.41 & 8.63 & 7.21 8.53 & 8.53 & 7.12 $ cat .data_3 10.31 8.50 7.40 10.34 8.53 7.81 8.22 8.62 7.78 10.16 8.53 7.44 10.41 8.38 7.63 10.38 8.57 8.03 10.13 8.66 7.41 8.50 8.60 7.15 10.41 8.63 7.21 8.53 8.53 7.12 addTableTexTags.sh #!/bin/bash sed -e "s@[[:space:]]@\t\&\t@g" -e "s@[[:space:]]*&*[[:space:]]*\$@\t \\ \\\\n@g" // Tried Escaping "\\" with "/" here and there // but cannot get a line ending with "\\ \n".

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  • Execute a method less times possible - PHP

    - by serhio
    I have a site in multiple languages. I have a method that returns me the today currencies in a array. I display that currencies in a table then. // --- en/index.php <?php include_once "../exchangeRates.php"; $currencies = ReadExchangeRates(); // --- fr/index.php <?php include_once "../exchangeRates.php"; $currencies = ReadExchangeRates(); ... // somewhere in the page <td><?php echo $currencies["eur"]["today"]; ?></td> So, every time I load, en/ or fr/ or other language, I request the exchange rates from a external site. Can I optimize this behavior (reading once per day or session)? maybe to store a global variable and check the update date?

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  • Windows server issue with a product

    - by peter
    Can you tell me the meaning of this statement.I am using windows 2008 server OS Log Problem must be changed so that it elevates privileges for a user executing the Problem. its done by creating a manifest that indicates that Problem needs Administrator privileges.

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  • Why C++ is (one of) the best language to learn at first [closed]

    - by AlexV
    C++ is one of the most used programming language in the world since like 25+ years. My first job as programmer was in C++ and I coded in C++ everyday for nearly 4 years. Now I do mostly PHP, but I will forever cherish this C++ background. C++ has helped me understand many "under the hood" features/behaviors/restrictions of many other (and different) programming languages like PHP and Delphi. I'm a full time programmer for 6+ years now and since I have a quite varied programming background I often get questions by "newbies" as where to start to become a "good" programmer. I think C++ is one of the best language to start with because it gives you a real usefull experience that will last and will teach you how things work under the hood. It's not the easier one to learn for a newbie, but in my opinion it's the one who will reward the most in long term. I would like to know your opinion on this matter to add to my arguments when I guide "newbies". After this introduction, here's my question : Why C++ is for you (one of) the best language to learn at first. Since it's subjective, I've marked this question as community wiki.

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  • How to provide global functionality in multi-user database app

    - by Mike B
    I have been building a multi-user database application (in C#/WPF 4.0) that manages tasks for all employees of a company. I now need to add some functionality such as sending an email reminder to someone when a critical task is due. How should this be done? Obviously I don’t want every instance of the program to be performing this function (Heh each user would get 10+ emails). Should I add the capability to the application as a "Mode" and then run a copy on the database server in this mode or would it be better to create a new app altogether to perform "Global" type tasks? Is there a better way?

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  • AWK: how to reuse a result NR-times without removing END?

    - by HH
    How can I get all differences, not just one? I want to use the calculated result for each item in the third column. The dilemma is that if I remove END I can print $3 but cannot have ave. If I leave END I have ave but not all differences. awk '{sum+=$3} END {ave=sum/NR} END {print $3-ave}' coriolis_data -0.00964 // I want to see the rest differences, how? coriolis_data .105 0.005 0.9766 0.0001 0.595 0.005 .095 0.005 0.9963 0.0001 0.595 0.005 .115 0.005 0.9687 0.0001 0.595 0.005 .105 0.005 0.9693 0.0001 0.595 0.005 .095 0.005 0.9798 0.0001 0.595 0.005 .105 0.005 0.9798 0.0001 0.595 0.005 .095 0.005 0.9711 0.0001 0.595 0.005 .110 0.005 0.9640 0.0001 0.595 0.005 .105 0.005 0.9704 0.0001 0.595 0.005 .090 0.005 0.9644 0.0001 0.595 0.005

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  • Books on Debugging Techniques?

    - by zooropa
    Are there any books on debugging techniques? A friend of mine is learning to code and he asked me this question. I told him I don't know of any. Is it that you just have to go through the School of Hard Knocks to learn?

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  • SQL-wrappers (activerecord) to recommened for python?

    - by Horace Ho
    is there an activerecord (any similar SQL-wrapper) for python? which is good for: used in a server-side python script light-weight supports MySQL what I need to do: insert (filename, file size, file md5, the file itself) into (string, int, string, BLOB) columns if the same file (checksum + filename) does not exist in db thx

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