Search Results

Search found 10295 results on 412 pages for 'rails beginner'.

Page 199/412 | < Previous Page | 195 196 197 198 199 200 201 202 203 204 205 206  | Next Page >

  • How can I "override" deepcopy in Python?

    - by Az
    Hi there, I'd like to override __deepcopy__ for a given SQLAlchemy-mapped class such that it ignores any SQLA attributes but deepcopies everything else that's part of the class. I'm not particularly familiar with overriding any of Python's built-in objects in particular but I've got some idea as to what I want. Let's just make a very simple class User that's mapped using SQLA. class User(object): def __init__(self, user_id, name): self.user_id = user_id self.name = name I've used dir() to see, before and after mapping, what SQLAlchemy-specific attributes there are and I've found _sa_class_manager and _sa_instance_state. Provided those are the only ones how would I ignore that when defining __deepcopy__? Also, are there any attributes the SQLA injects into the mapped object? (I asked this in a previous question (as an edit a few days after I selected an answer to the main question, though) but I think I missed the train there. Apologies for that.)

    Read the article

  • Does everything after my try statement have to be encompassed in that try statement to access variab

    - by Mithrax
    I'm learning java and one thing I've found that I don't like, is generally when I have code like this: import java.util.*; import java.io.*; public class GraphProblem { public static void main(String[] args) { if (args.length < 2) { System.out.println("Error: Please specify a graph file!"); return; } FileReader in = new FileReader(args[1]); Scanner input = new Scanner(in); int size = input.nextInt(); WeightedGraph graph = new WeightedGraph(size); for(int i = 0; i < size; i++) { graph.setLabel(i,Character.toString((char)('A' + i))); } for(int i = 0; i < size; i++) { for(int j = 0; j < size; j++) { graph.addEdge(i, j, input.nextInt()); } } // .. lots more code } } I have an uncaught exception around my FileReader. So, I have to wrap it in a try-catch to catch that specific exception. My question is does that try { } have to encompass everything after that in my method that wants to use either my FileReader (in) or my Scanner (input)? If I don't wrap the whole remainder of the program in that try statement, then anything outside of it can't access the in/input because it may of not been initialized or has been initialized outside of its scope. So I can't isolate the try-catch to just say the portion that intializes the FileReader and close the try statement immediately after that. So, is it the "best practice" to have the try statement wrapping all portions of the code that are going to access variables initialized in it? Thanks!

    Read the article

  • Make: how make all hidden files in the current makefile?

    - by HH
    It traverses to bottom dirs for some unknown reason: Errorsome /bin/sh: .??*: not found make[23]: Entering directory `/m/user/files/dir' make clean Makefile all: make clean #The wildcard is the bug. I want to make all hidden files in the current makefile. #It should match .<some char><some char><any char arbitrary times> make $$(.??*) #I want to replace below-like-tihngs with a wildcard above # make .lambda # make .lambda_t clean: -rm .??* .lambda: #do something .lambda_t:

    Read the article

  • vector related memory allocation question

    - by memC
    hi all, I am encountering the following bug. I have a class Foo . Instances of this class are stored in a std::vector vec of class B. in class Foo, I am creating an instance of class A by allocating memory using new and deleting that object in ~Foo(). the code compiles, but I get a crash at the runtime. If I disable delete my_a from desstructor of class Foo. The code runs fine (but there is going to be a memory leak). Could someone please explain what is going wrong here and suggest a fix? thank you! class A{ public: A(int val); ~A(){}; int val_a; }; A::A(int val){ val_a = val; }; class Foo { public: Foo(); ~Foo(); void createA(); A* my_a; }; Foo::Foo(){ createA(); }; void Foo::createA(){ my_a = new A(20); }; Foo::~Foo(){ delete my_a; }; class B { public: vector<Foo> vec; void createFoo(); B(){}; ~B(){}; }; void B::createFoo(){ vec.push_back(Foo()); }; int main(){ B b; int i =0; for (i = 0; i < 5; i ++){ std::cout<<"\n creating Foo"; b.createFoo(); std::cout<<"\n Foo created"; } std::cout<<"\nDone with Foo creation"; std::cout << "\nPress RETURN to continue..."; std::cin.get(); return 0; }

    Read the article

  • [Python] OR in regular expression?

    - by www.yegorov-p.ru
    Hello. I have text file with several thousands lines. I want to parse this file into database and decided to write a regexp. Here's part of file: blablabla checked=12 unchecked=1 blablabla unchecked=13 blablabla checked=14 As a result, I would like to get something like (12,1) (0,13) (14,0) Is it possible?

    Read the article

  • preg_match basics question.

    - by Yo-L
    Hi all. Got some trouble with my preg_match. The code. $text = 'tel: 012 213 123. mobil: 0303 11234'; $regex_string = '/(tel|Tel|TEL)[\s|:]+(.+)[\.|\n]/'; preg_match($regex_string , $text, $match); And I get this result in $match[2] "012 213 123. mobil: 023 123 123" First question. I want the regex to stop at the .(dot) but it doesent. Can someone explain to why it isnt? Second question. preg_match uses () to get their match. Is it possible to skip the parentheses surrounding the different "Tel" and still get the same functionality? Thnx all stackoverflow is great :D

    Read the article

  • How do Arrays work in C#?

    - by Slateboard
    I know that they are used to store data, but I have a difficult time understanding exactly how to use them in a program. In addition, I found this site with a tetris clone tutorial (the actual tutorial is missing). It uses arrays, but I can't really make sense of how it works. Here's an example of the code - public int[, ,] TShape = new int[4, 4, 2] { {{1, 0}, {0, 1}, {1, 1}, {2, 1}}, {{1, 0}, {0, 1}, {1, 1}, {1, 2}}, {{0, 0}, {1, 0}, {2, 0}, {1, 1}}, {{0, 0}, {0, 1}, {1, 1}, {0, 2}}}; Could it be that I'm looking too hard into this, or perhaps there's something I'm not grasping about it?

    Read the article

  • I'm having a problem identifying a floating point exception.

    - by Peter Stewart
    I'm using c++ in visual studio express to generate random expression trees for use in a genetic algorithm type of program. Because they are random, the trees often generate (I'll call them exceptions, I'm not sure what they are) Thanks to a suggestion by George, I turned the mask _MCW_EM on so that hardware interrupts are turned off. (the default) So, the program runs uninterrupted, but some of the values returned are: -1.#INF, -1.#NAN, -1.#INV. I don't know how to identify these so that I can throw an exeption: if ( variable == -1.#INF) ?? DigitalRoss in this post seemed to have the solution, but as I understood it I couldn't make it work. I've been looking all over the place for this simple bit of code, that I assumed would be used all the time, but have had no luck. thanks

    Read the article

  • Java method: retrieve the inheriting type

    - by DrDro
    I have several classes that extend C and I would need a method that accepts any argument of type C. But in this method I would like to know if I'm dealing with A or B. * public A extends C public B extends C public void goForIt(C c)() If I cast how can I retrieve the type in a clean way (I just read using getClass or instanceof is often not the best way). *Sorry but I can't type closing braces

    Read the article

  • In what order should the Python concepts be explained to absolute beginners?

    - by Tomaž Pisanski
    I am teaching Python to undergraduate math majors. I am interested in the optimal order in which students should be introduced to various Python concepts. In my view, at each stage the students should be able to solve a non-trivial programming problem using only the tools available at that time. Each new tool should enable a simpler solution to a familiar problem. A selection of numerous concepts available in Python is essential in order to keep students focused. They should also motivated and should appreciate each newly mastered tool without too much memorization. Here are some specific questions: For instance, my predecessor introduced lists before strings. I think the opposite is a better solution. Should function definitions be introduced at the very beginning or after mastering basic structured programming ideas, such as decisions (if) and loops (while)? Should sets be introduced before dictionaries? Is it better to introduce reading and writing files early in the course or should one use input and print for most of the course? Any suggestions with explanations are most welcome.

    Read the article

  • Generics List Interface...newb question

    - by newToProgramming
    The List interface is the following: public interface List<E>{ public boolean add(Object e); public boolean remove(Object e); public boolean contains(Object e); ...etc Why aren't the add, remove and contains methods written like the following? public boolean add(E e) public boolean remove(E e) public boolean contains(E e)

    Read the article

  • How to use Scanner to accept only valid int as input

    - by John
    I'm trying to make a small program more robust and I need some help with that. Scanner kb = new Scanner(System.in); int num1; int num2 = 0; System.out.print("Enter number 1: "); num1 = kb.nextInt(); while(num2<num1) { System.out.print("Enter number 2: "); num2 = kb.nextInt(); } Number 2 has to be greater than number 1 Also I want the program to automatically check and ignore if the user enters a character instead of a number. Because right now when a user enters for example r instead of a number the program just exits.

    Read the article

  • How to get global access to enum types in C#?

    - by lala
    This is probably a stupid question, but I can't seem to do it. I want to set up some enums in one class like this: public enum Direction { north, east, south, west }; Then have that enum type accessible to all classes so that some other class could for instance have: Direction dir = north; and be able to pass the enum type between classes: public void changeDirection(Direction direction) { dir = direction; } I thought that setting the enum to public would make this automatically possible, but it doesn't seem to be visible outside of the class I declared the enum in.

    Read the article

  • Assigning a value to a variable gets stored in the wrong spot?

    - by scribbloid
    Hello, I'm relatively new to C, and this is baffling me right now. It's part of a much larger program, but I've written this little program to depict the problem I'm having. #include <stdio.h> int main() { signed int tcodes[3][1]; tcodes[0][0] = 0; tcodes[0][1] = 1000; tcodes[1][0] = 1000; tcodes[1][1] = 0; tcodes[2][0] = 0; tcodes[2][1] = 1000; tcodes[3][0] = 1000; tcodes[3][1] = 0; int x, y, c; for(c = 0; c <= 3; c++) { printf("%d %d %d\r\n", c, tcodes[c][0], tcodes[c][1]); x = 20; y = 30; } } I'd expect this program to output: 0 0 1000 1 1000 0 2 0 1000 3 1000 0 But instead, I get: 0 0 1000 1 1000 0 2 0 20 3 20 30 It does this for any number assigned to x and y. For some reason x and y are overriding parts of the array in memory. Can someone explain what's going on? Thanks!

    Read the article

  • database connection OK,result not appear

    - by klox
    hi..all.for now i'm already connected to database but the result not appear at Tuner range is"+res+"this is my code: var str=data[0]; var matches=str.match(/[EE|EJU].*D/i); $.ajax({ type:"post", url:"process1.php", data:"tversion="+matches+"&action=tunermatches", cache:false, async:false, success: function(res){ $('#value').replacewith("<div id='value'><h6>Tuner range is"+res+".</h6></div>"); } }); }); and this is my process file: //connect to database $dbc=mysql_connect(_SRV,_ACCID,_PWD) or die(_ERROR15.": ".mysql_error()); $db=mysql_select_db("qdbase",$dbc) or die(_ERROR17.": ".mysql_error()); switch(postVar('action')) { case 'tunermatches' : tunermatches(postVar('tversion')); break; function tunermatches($tversion)){ $Tuner=mysql_real_escape_string($tversion); $sql= "SELECT remark FROM settingdata WHERE itemname='Tuner_range' AND itemdata='".$Tunermatches."'"; $res=mysql_query($sql) or die (_ERROR26.":".mysql_error()); $dat=mysql_fetch_array($res,MYSQL_NUM); if($dat[0]>0) { echo $dat[0]; } mysql_close($dbc); }

    Read the article

  • How do you keep application logic separate from UI when UI components have built-in functionality?

    - by Al C
    I know it's important to keep user interface code separated from domain code--the application is easier to understand, maintain, change, and (sometimes) isolate bugs. But here's my mental block ... Delphi comes with components with methods that do what I want, e.g., a RichText Memo component lets me work with rich text. Other components, like TMS's string grid not only do what I want, but I paid extra for the functionality. These features put the R in RAD. It seems illogical to write my own classes to do things somebody else has already done for me. It's reinventing the wheel [ever tried working directly with rich text? :-) ] But if I use the functionality built into components like these, then I will end up with lots of intermingled UI and domain code--I'll have a form with most of my code built into its event handlers. How do you deal with this issue? ... Or, if I want to continue using the code others have already written for me, how would you suggest I deal with the issue?

    Read the article

  • Creating a unique id for a Core Data program on the iPhone

    - by Big Twisty
    I am fairly new at programming in Objective-C, having been a windows programmer since I was a kid. I am falling in LOVE with it. I am, however, having a bit of trouble figuring out this Core Data stuff. How do I create a new entry with a unique ID? In SQL I would just declare one field as an autoincrement field. I'm not seeing anything like that here, but I could just be missing something. I just want an auto incrementing NSInteger field, so when I manually add items to the database, I will have some form of reference to them.

    Read the article

  • Using mercurial for web-design version control (dealing with images)

    - by Acorn
    I'm very new to Version Control, and I was wondering if I could get some advice on how it can fit into website design. At the moment I'm working on a typical, simple website that includes images: A few .html files and a .css file One folder full of photographs Another folder with the corresponding thumbnails Can I just put the whole lot in a repository? Or is there a better way I could apply Version Control to it? How should I deal with the images? edit: How well will it work with changes to the images? What if I decide to try and optimise my photographs or resize them. I wont be able to see what exactly changed about the images, should comments be enough to keep track of that?

    Read the article

  • Regex, replace path to resource, modify resource name

    - by jerome
    Hi all, I'd like to use a JS regex to take a string such as the following: 'http://www.somedomain.com/some_directory/some_other_directory/some_image.jpg' And turn it into this: 'http://www.some_other_domain.com/another_directory/yet_another_directory/size1_some_image.jpg' Any hints? Additionally, any pointers for books or other resources that give a gentle introduction to mastering regexes in JS and other languages?

    Read the article

  • How do I splice a python string programmatically?

    - by Robin Welch
    Very simple question, hopefully. So, in Python you can split up strings using indices as follows: >>> a="abcdefg" >>> print a[2:4] cd but how do you do this if the indices are based on variables? E.g. >>> j=2 >>> h=4 >>> print a[j,h] Traceback (most recent call last): File "<stdin>", line 1, in ? TypeError: string indices must be integers

    Read the article

  • Returning currently displayed index of an array Javascript...

    - by Jeff Kindred
    I have a simple array with x number of items. I am displaying them individually via a link click... I want to update a number that say 1 of 10. when the next one is displayed i want it to display 2 of 10 etc... I have looked all around and my brain is fried right now... I know its simple I just cant get it out. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <title>Page Title</title> <link rel="stylesheet" href="style.css" type="text/css" media="screen" charset="utf-8"/> <script type="text/javascript"> var quotations = new Array() quotations[0]= "1" quotations[1]= "2" quotations[2]= "3" quotations[3]= "4" quotations[4]= "5" quotations[5]= "6" quotations[6]= "7" numQuotes = quotations.length; curQuote = 1; function move( xflip ) { curQuote = curQuote + xflip; if (curQuote > numQuotes) { curQuote = 1 ; } if (curQuote == 0) { curQuote = numQuotes ; } document.getElementById('quotation').innerHTML=quotations[curQuote - 1]; } var curPage = //this is where the current index should go </script> </head> <body> <div id="quotation"> <script type="text/javascript">document.write(quotations[0]);</script> </div> <div> <p><a href="javascript();" onclick="move(-1)">GO back</a> <script type="text/javascript">document.write(curPage + " of " + numQuotes)</script> <a href="javascript();" onclick="move(1)">GO FORTH</a></p> </div> </body> </html>

    Read the article

  • What is the best way to learn VB/VBA?

    - by Noah
    I have wanted to learn VB and VBA for a long time. My school offers a coarse, but it doesn't fit with the rest of my schedule. It will be my first programing language. I was considering using the textbook my school uses (An introduction to programing using visual basic 2008, but I wold get the 2010 version), but I was wondering if there were better resources I could use. I mainly want to lean to learn VBA so I cam create macros and other tools for MS Word. Please understand that this is the fist time I will be programming and I am teaching myself (with the books/online resources).

    Read the article

< Previous Page | 195 196 197 198 199 200 201 202 203 204 205 206  | Next Page >