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• Got a question I don't understand, can anyone make sense of it?

  - by user275074

  Question on a on-line resource paper: Create javascript so that the following methods produce the output listed next it. circle = new Circle(); console.log(circle.get_area()); // 3.141592653589793 circle.set_radius(10); console.log(circle.get_area()); // 314.1592653589793 console.log(circle); // the radius of my circle is 10 and it's area is 314.1592653589793 Can anyone understand what is being asked?

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• In python, a good way to remove a list from a list of dicts

  - by ensnare

  I have a list of dicts: list = [{'title': u'Politics', 'id': 1L, 'title_url': u'Politics'}, {'id': 3L, 'title_url': u'Test', 'title': u'Test'}] I'd like to remove the list item with title = 'Test' What is the best way to do this given that the order of the key/value pairs change? Thanks.

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• In c++ is there any Events/delegates/interfaces/notifications! anything?

  - by Bach

  Say i have these classes ViewA and ViewB In objective C using the delegate pattern I could do @protocol ViewBDelegate{ - (void) doSomething(); } then in ViewB interface: id<ViewBDelegate> delegate; then in ViewA implementation i set the delegate: viewB.delegate = self; and now I can call in doSomething from viewB onto any that unknown type delegate. [delegate doSomething]; "C++ How to Program" has been the worse read an can't find simple examples that demonstrates basic design patterns. What i'm looking for in C++ is: events ActionScript and java either delegates or notifications in Objective C anything that allows class A, Class B and Class C to know that ClassX didSomething()!!! thanks

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• utf8 format in xml

  - by hussain

  i want to know how to store this è (this type of symbols) in xml file if i store this symbol in xml file.. the file shows this symbol like ? i was inserted in front of xml file is <?xml version="1.0" encoding="UTF-8"?> but that doest not shows correct thanks and advance

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• JButtons re-enable themselves after being disabled

  - by Anarchist

  I have an array of JButtons which form a keypad interface. After six numbers are entered I want to disable the keypad so that no further numbers can be entered by the user. I have written the code and the buttons do disable until the mouse hovers above any of them, then the buttons seem to re-enable themselves and run actionEvents added to them. The full code is available here. Possible things that I think are wrong. There is some sort of MouseListener which is ignoring when I set button.setEnabled(false); I haven't separated attributes from the buildGUI(); correctly, I only did this anyway so that the inner class could access them. Possibly something to do with the gridLayout as disabling the buttons seems to work for my services JPanel buttons.

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• I know the big picture but can't put it in place

  - by Simbilim

  Hi, I'm interested in web development and by that I mean the bigger projects like facebook or twitter. I know the basics of java, css, php and mysql. I know there is a lot more out there. I read about it. But I don't know what the purpose is and how to put in place. Things like: Scribe, thrift, casandra, Unix/Linux, shell/perl/python scripting, PostgreSQL, MongoDB, non-relational NoSQL datastores, JVM, nginx I want to know why they need it, how they use it and what te purpose is. What I need is a book like technical background of facebook for dummies or so. Are there any books or websites that explain this from scratch? Thank you!

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• Performance hit from C++ style casts?

  - by Trevor Boyd Smith

  I am new to C++ style casts and I am worried that using C++ style casts will ruin the performance of my application because I have a real-time-critical deadline in my interrupt-service-routine. I heard that some casts will even throw exceptions! I would like to use the C++ style casts because it would make my code more "robust". However, if there is any performance hit then I will probably not use C++ style casts and will instead spend more time testing the code that uses C-style casts. Has anyone done any rigorous testing/profiling to compare the performance of C++ style casts to C style casts? What were your results? What conclusions did you draw?

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• How to create conditions in mysql (use of 'if')?

  - by Audel

  This code works fine to find an available room within certain date, but it does not work to show a room that has been booked and canceled The "hotel" has 4 rooms and 1 of them has been booked an canceled So even if I make a cancelation, the select method keeps giving me 3 results. Maybe because the second AND is still running. So basically what I need is check if the room is booked in the selected dates if it has been booked, check if its canceled if it has been canceled, or not booked display it. Otherwise not   SELECT RoomNo, NightCost FROM room, room_types, booking WHERE typeid = fk1_typeid and double_bed=1 and single_bed=0 AND canceled = '1' in (SELECT canceled from booking, room_booking where bookingid = fk2_bookingid) AND RoomNo not in (SELECT fk1_RoomNo FROM room_booking WHERE '2010-04-02' between Check_in and Check_Out or '2010-04-03' between Check_in and Check_Out) ; I tried to be as clear as possible, i will be around to give more details if needed

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• jQuery: Adding li element only if it not already there?

  - by Legend

  I am constructing an <li> element like this: var element = $("<li></li>") .html(mHTML) .attr('id', "elemid"); I am trying to add this element to a <ul> element only if it doesn't already exist. Any ideas on how to do this? Am I supposed to use contains() to see if the ul element contain the html and then decide? For instance, <ul id="elemul"> <li id="elemli1">Element 1</li> <li id="elemli2">Element 2</li> <li id="elemli3">Element 3</li> </ul> If I try adding Element 1, it should not add it. What should I do if its a longer string (not really long but about 150 characters). Do I go about using hashmaps?

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• Creating a Modeless Dialog

  - by Tom

  I'm trying to create a child modeless dialog of a dialog and currently I'm using these style parameters: STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION | WS_SYSMENU EXSTYLE WS_EX_TOOLWINDOW I'm not being able to transfer the control its parent dialog once i try to create its child dialog. is there anything else I'm missing in the process to make the dialog modeless?

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• Elegant min/max absolute values in java

  - by Stefano Borini

  I need to get the minimum and maximum values in a collection of floating point values, after applying an absolute value conversion. In python I would do this min(map(abs, [-5, -7, 10, 2])) how can I perform the same operation in java in the most elegant way?

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• Using Mokito, how do I match against the key-value pair of a map?

  - by Sean

  I am need to send a return specific value from a mock object based on a specific key value. concreate class: map.put("xpath", "PRICE"); search(map); Test case: IOurXMLDocument mock = mock(IOurXMLDocument.class); when(mock.search(.....need help here).thenReturn("$100.00"); how do I mock this method call for this key value pair?

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• Codeigniter: simple form function

  - by Kevin Brown

  I'm stuck writing a simple form...I feel dumb. Here's my controller: function welcome_message(){ //Update welcome message $id = $this->session->userdata('id'); $profile['welcome_message'] = $this->input->post('welcome_message'); $this->db->update('be_user_profiles',$profile, array('user_id' => $id)); } And the html: <?php print form_open('home/welcome_message')?> <input type="checkbox" value="0" checked="false">Don't show me this again</input> <p> <input class="button submit" type="submit" class="close-box" value="Close" /> </p> <?php print form_close()?> Edit I simply need it to submit to a private function and return to the home page (page submitted from).

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• About Sorting Algorithms applied to Stacks and Queues

  - by matin1234

  I want to know why we always use Sorting algorithm like (Insertion Sort or Merge Sort,...) just for lists and arrays? And why we do not use these algorithms for stack or queue?

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• What are "named tuples" in Python?

  - by Denilson Sá

  Reading the changes in Python 3.1, I found something... unexpected: The sys.version_info tuple is now a named tuple: I never heard about named tuples before, and I thought elements could either be indexed by numbers (like in tuples and lists) or by keys (like in dicts). I never expected they could be indexed both ways. Thus, my questions are: What are named tuples? How to use them? Why/when should I use named tuples instead of normal tuples? Why/when should I use normal tuples instead of named tuples? Is there any kind of "named list" (a mutable version of the named tuple)?

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• mapping list of different types implementing same function?

  - by sisif

  I want to apply a function to every element in a list (map) but the elements may have different types but all implement the same function (here "putOut") like an interface. However I cannot create a list of this "interface" type (here "Outputable"). How do I map a list of different types implementing the same function? main :: IO () main = do map putOut lst putStrLn "end" where lst :: [Outputable] -- ERROR: Class "Outputable" used as a type lst = [(Out1 1),(Out2 1 2)] class Outputable a where putOut :: a -> IO () -- user defined: data Out1 = Out1 Int deriving (Show) data Out2 = Out2 Int deriving (Show) instance Outputable Out1 where putOut out1 = putStrLn $ show out1 instance Outputable Out2 where putOut out2 = putStrLn $ show out2 I cannot define it this way: data Out = Out1 Int | Out2 Int Int putOut Out1 = ... putOut Out2 = ... because this is a library and users should be able to extend Out with their own types

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• 3D and AI basics. The foundation before the coding.

  - by Allan

  Hi, everyone. (If you have the time and patience:) I've recently made the decision to study programming seriously and I'm about to order TAOCP and Concrete Mathematics to begin my studies (please don't get caught up on this). I'm very much interested in learning and understanding how 3D works but I'm aware that if I plan to do it right there's still a long walk before I get to actually play with 3D coding. Now to the question.. (tl;dr) Excluding programming itself, what disciplines do I have to be familiar with to code 3D? What kinds of mathematics? Physics? What else? What books do you recommend on such subjects? Now read it all again but replacing "3D" with "AI". Please don't recommend computer-specific books. The question is about the foundation to be learned before using the machine. Also, if possible, please keep the list brief; I plan to order one book on each subject but no more than that for now. Excuse me for any English mistakes, it's not my first language. Thank you.

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• C++: how to publicly inherit from a base class but make some of public methods from the base class p

  - by powerboy

  For example, class Base has two public methods: foo() and bar(). Class Derived is inherited from class Base. In class Derived, I want to make foo() public but bar() private. Is the following code the correct and natural way to do this? class Base { public: void foo(); void bar(); }; class Derived : public Base { private: void bar(); };

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• How to append() an element and set its style with css() at the same time with jQuery

  - by Acorn

  I tried: $('#canvas').append('<div class="tile"></div>').css({left: leftPos, top: topPos});, but that sets the style of #canvas rather than the appended element. I then tried: $('#canvas').append(('<div class="tile"></div>').css({left: leftPos, top: topPos}));, but that gives the error "Object <div class="tile"></div> has no method 'css'". How can I add the element and set its style at the same time?

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• How to join list of strings?

  - by satsurae

  Hi all, This is probably seriously easy to solve for most of you but I cannot solve this simply putting str() around it can I? I would like to convert this list: ['A','B','C'] into 'A B C'. Thanks in advance!!

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• How to wrap a C function whose parameters are pointer to structs, so that it can be called from Lua?

  - by pierr

  I have the follwing C function. How should I wrap it so it can be called from a Lua script? typedef struct tagT{ int a ; int b ; } type_t; int lib_a_f_4(type_t *t) { return t->a * t->b ; } I know how to wrapr it if the function parameter type were int or char *. Should I use table type for a C structure? EDIT: I am using SWIG for the wraping , according to this doc, It seems that I should automatically have this funtion new_type_t(2,3) , but it is not the case. If you wrap a C structure, it is also mapped to a Lua userdata. By adding a metatable to the userdata, this provides a very natural interface. For example, struct Point{ int x,y; }; is used as follows: p=example.new_Point() p.x=3 p.y=5 print(p.x,p.y) 3 5 Similar access is provided for unions and the data members of C++ classes. C structures are created using a function new_Point(), but for C++ classes are created using just the name Point().

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• Java NullPointerException. Why?

  - by user292844

  I am new to Java. I just read that class variables in Java have default value. I tried the following program. I was expecting to get the output as 0, which is the default value on an integer, but I get the NullPointerException. What am I missing? class Test{ static Integer iVar; public static void main(String...args) { System.out.println(iVar.intValue()); } }

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• how to see contents of a.out file?

  - by abhilashm86

  The executable file of c++ will contain linkers, modules and others, i would like to look into its contents, i'm using linux, how can i view contents of a.out? which command should use to browse a.out, text editors wont show the contents......

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• for line in open(filename)

  - by foosion

  I frequently see python code similar to for line in open(filename): do_something(line) When does filename get closed with this code? Would it be better to write with open(filename) as f: for line in f.readlines(): do_something(line)

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• number of elements in a static array of a predefined size

  - by cppb

  I have an array like this: int a[100]; I am filling only the first 4 elements in this array: a[0] = 1; a[1] = 2; a[2] = 3; a[3] = 4; When I do sizeof(a)/sizeof(a[0]) it returns 100. Is there a way I can get number of elements to which I have assinged a value and thus filtering out the remaining 96 unassigned elements? thanks

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