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  • FieldError when annotating over foreign keys

    - by X_9
    I have a models file that looks similar to the following: class WithDate(models.Model): adddedDate = models.DateTimeField(auto_now_add=True) modifiedDate = models.DateTimeField(auto_now=True) class Meta: abstract = True class Match(WithDate): ... class Notify(WithDate): matchId = models.ForeignKey(Match) headline = models.CharField(null=True, blank=True, max_length=10) For each Match I'm trying to get a count of notify records that have a headline. So my call looks like matchObjs = Match.objects.annotate(notifies_made=Count('notify__headline__isnull')) This keeps throwing a FieldError. I've simplified the query down to matchObjs = Match.objects.annotate(notifies_made=Count('notify')) And I still get the same FieldError... I've seen this work in other cases (other documentation, other SO questions like this one) but I can't figure out why I'm getting an error. The specific error that is returned is as follows: Cannot resolve keyword 'notify' into field. Choices are: (all fields from Match model) Does anyone have a clue as to why I can't get this annotation to work across tables? I'm baffled after looking at the other SO question and various Django docs where I've seen this done. Edit: I am using Django 1.1.1

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  • Confused about GNU `sort(1)` of a numerical sub field

    - by Chen Levy
    I wish to sort a space separated table, with the numerical value that found on the 2nd field. I can assume that the 2nd field is always fooN but the length of N is unknown: antiq. foo11 girls colleaguing foo2 Leinsdorf Cousy foo0 Montgomeryville bowlegged foo1 pollack Chevrier foo10 ill-conceived candlebomb foo3 seventieths autochthony foo101 re-enable beneficiate foo100 osteometric I read man sort(1) and played with all sort of options. On my system I found the line: sort -n -k2.5 table to work. My question is why? According to the man page: -k, --key=POS1[,POS2] start a key at POS1, end it at POS 2 (origin 1) ... POS is F[.C][OPTS], where F is the field number and C the characterposition in the field. OPTS is one or more single-letter ordering options, which override global ordering options for that key. If no key is given, use the entire line as the key. So why sort -n -k2.4 table don't work and sort -n -k.5 does?

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  • Haskell: Pattern Matching with Lists

    - by user1670032
    I'm trying to make a function that takes in a list, and if one of the elements is negative, then any elements in that list that are equal to its positive counterpart should be changed to 0. Eg, if there is a -2 in a list, then all 2's in that list should be changed to 0. Any ideas why it only works for some cases and not others? I'm not understanding why this is, I've looked it over several times. changeToZero [] = [] changeToZero [x] = [x] changeToZero (x:zs:y:ws) | (x < 0) && ((-1)*(x) == y) = x : zs : 0 : changeToZero ws changeToZero (x:xs) = x : changeToZero xs *Main changeToZero [-1,1,-2,2,-3,3] [-1,1,-2,2,-3,3] *Main changeToZero [-2,1,2,3] [-2,1,0,3] *Main changeToZero [-2,1,2,3,2] [-2,1,0,3,2] *Main changeToZero [1,-2,2,2,1] [1,-2,2,0,1]

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  • Interface that Entails the Implementation of Indexer

    - by Ngu Soon Hui
    I am looking for a framework-defined interface that declares indexer. In other words, I am looking for something like this: public interface IYourList<T> { T this[int index] { get; set; } } I just wonder whether .Net framework contains such interface? If yes, what is it called? You might ask why I can't just create the interface myself. Well, I could have. But if .Net framework already has that why should I reinvent the wheel?

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  • Tortoise Check-in error Checksum mismatch

    - by coffeeaddict
    I cannot figure out why I get this error during check-in. I checked in successful only a few hours ago so not sure why now it's complaining Error: Commit failed (details follow): Error: Checksum mismatch for Error: 'C:\sss\sss\trunk\xxxx\.svn\text-base\Header.ascx.svn-base'; expected: Error: '3cee96f580409a1711a47541a07860dd', actual: 'a5fc0f8819b88bf32ab38d4c9a6b0654' Error: Try a 'Cleanup'. If that doesn't work you need to do a fresh checkout. I got latest and also performed a clean-up which said successful so not sure what else to do.

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  • What does it mean to do/determine something "programmatically"?

    - by Chris Lutz
    Programmatically. (alt. programmically) I've never used it, but I see it in questions a lot, i.e. "How to programmatically determine [insert task here]". Firefox immediately tells me that neither of these two words are real (at least, it doesn't recognize them). I've also never seen them used anywhere but here. 1) What does it mean to do/determine something "programmatically"? 2) Why do so many people ask how to do/determine something "programmatically"? Isn't it assumed that, if you're asking how to do something on a programming help board, you're asking how to do it "programmatically"? 3) Why is it that I've never seen the word "programmatically" anywhere else?

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  • Need help for this syntax: "#define LEDs (char *) 0x0003010"

    - by Noge
    I'm doing programming of a softcore processor, Nios II from Altera, below is the code in one of the tutorial, I manage to get the code working by testing it on the hardware (DE2 board), however, I could not understand the code. #define Switches (volatile char *) 0x0003000 #define LEDs (char *) 0x0003010 void main() { while (1) *LEDs = *Switches; } What I know about #define is that, it is either used to define a constant, or a macro, but why in the above code, there are casting like, (char *) 0x0003010, in #define? why the 2 constants, Switches and LEDs act like a variable instead of a constant? Thanks in advance !

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  • Pro/con: Initializing a variable in a conditional statement

    - by steffenj
    In C++ you can initialize a variable in an if statement, like so: if (CThing* pThing = GetThing()) { } Why would one consider this bad or good style? What are the benefits and disadvantages? Personally i like this style because it limits the scope of the pThing variable, so it can never be used accidentally when it is NULL. However, i don't like that you can't do this: if (CThing* pThing = GetThing() && pThing->IsReallySomeThing()) { } If there's a way to make the above work, please post. But if that's just not possible, i'd still like to know why. Question borrowed from here, similar topic but PHP.

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  • C# regex: negative lookahead fails with the single line option

    - by Sylverdrag
    I am trying to figure out why a regex with negative look ahead fails when the "single line" option is turned on. Example (simplified): <source>Test 1</source> <source>Test 2</source> <target>Result 2</target> <source>Test 3</source> This: <source>(?!.*<source>)(.*?)</source>(?!\s*<target) will fail if the single line option is on, and will work if the single line option is off. For instance, this works (disables the single line option): (?-s:<source>(?!.*<source>)(.*?)</source>(?!\s*<target)) My understanding is that the single line mode simply allows the dot "." to match new lines, and I don't see why it would affect the expression above. Can anyone explain what I am missing here?

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  • Need to read .symtab

    - by user361190
    I am frustrated. I have a simple doubt .. I compile a simple program with gcc and if I see the section header using objdump, it does not show the section ".symtab". for the same a.out file, readelf shows the section. see the below snip - [25] .symtab SYMTAB 00000000 000ca4 000480 10 26 2c 4 [26] .strtab STRTAB 00000000 001124 00025c 00 0 0 1 Why ? In the default linker script I don't find a definition for .symtab section. If I add a definition by myself like in the linker script : .... PROVIDE(__start_sym) .symtab : { *(.symtab)} PROVIDE(__end_sym) .... the difference b/w the addresses of __start_sym and __end_sym is zero, which means no such section is added in the output file. But the readelf is able to read the section and dump the contents of this section .. How ? why ?

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  • CSS: Size of buttons in Chrome is different than Firefox

    - by Hank
    I have the following HTML code: <style type="text/css"> .submitbutton{margin-left:-2px} </style> ... <form> ... <input class=submitbutton type=submit value="Create Listings" /> </form> In Firefox, the input button has more padding than in Chrome. Any ideas why? UPDATE: If you're wondering why I have the negative margin - it's because between the input field and the input button - there is too much space.

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  • I have a problem with the following Java code

    - by Sanjeev
    public class b { public static void main(String[] args) { byte b = 1; long l = 127; // b = b + l; // 1 if I try this then it does not compile b += l; // 2 if I try this then it does compile System.out.println(b); } } I am using this code but I have problem: I don't understand why b=b+l; is not compiling but if I write b+=l; then it compiles and runs. Please explain why this happens.

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  • How to get the "#" symbol in the :id into the redirect_to method in Rails

    - by Matthias Günther
    Hello, this is a silly questions but I don't understand, why rails isn't evaluating my string as expected. Here is my problem: I want to redirect to an url in the form ~/:controller/index/#_76 redirect_to :action => "index", :id => '#_76' But I'm getting the url in the form: ~/:controller/index/%25_76 and so my anchor for linking to a certain place in the website isn't working. Can someone please explain me, why rails makes this rendering? I think this hase something to do with url encoding. Again thanks for your help, I'm learning every day a little bit more about rails :).

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  • Opinions regarding C++ programming practice

    - by Sagar
    I have a program that I am writing, not too big. Apart from the main function, it has about 15 other functions that called for various tasks at various times. The code works just fine all in one file, and as it is right now. However, I was wondering if anyone had any advice on whether it is smarter/more efficient/better programming to put those functions in a separate file different from where main is, or whether it even matters at all. If yes, why? If no, why not? I am not new at C++, but definitely not an expert either, so if you think this question is stupid, feel free to tell me so. Thanks for your time!

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  • c# Generic overloaded method dispatching ambiguous

    - by sebgod
    Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

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  • Performance of Managed C++ Vs UnManaged/native C++

    - by bsobaid
    I am writing a very high performance application that handles and processes hundreds of events every millisecond. Is Unmanaged C++ faster than managed c++? and why? Managed C++ deals with CLR instead of OS and CLR takes care of memory management, which simplifies the code and is probably also more efficient than code written by "a programmer" in unmanaged C++? or there is some other reason? When using managed, how can one then avoid dynamic memory allocation, which causes a performance hit, if it is all transparent to the programmer and handled by CLR? So coming back to my question, Is managed C++ more efficient in terms of speed than unmanaged C++ and why?

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  • Properly releasing UITableViewController and UITableView directly added to a UIViewController

    - by JK
    I have a UIViewController (parentVC) to which I add a UITableViewController as follows (it is not pushed since the tableview only occupies about half the screen): tableVC = [[SmallTableVC alloc] initWithStyle:UITableViewStylePlain]; [self.view addSubview:tableVC.tableView]; In dealloc, I add [tableVC release]; Using instruments, I can see that the tableVC is indeed fully released when parentVC released, which is good, but I am not sure why as I thought that the UITableView of tableVC would have a retain count of 2 (1 for retention by tableVC and 1 for retention by parentVC). My intuition was that an additional [tableVC.tableView release] would be required, but adding it crashes the app. Why is tableVC released properly by the current code (if indeed it actually is)? Does a UITableViewController not retain its tableView? Thanks.

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  • C++ program runs slow in VS2008

    - by Nima
    I have a program written in C++, that opens a binary file(test.bin), reads it object by object, and puts each object into a new file (it opens the new file, writes into it(append), and closes it). I use fopen/fclose, fread and fwrite. test.bin contains 20,000 objects. This program runs under linux with g++ in 1 sec but in VS2008 in debug/release mode in 1min! There are reasons why I don't do them in batches or don't keep them in memory or any other kind of optimizations. I just wonder why it is that much slow under windows. Thanks,

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  • Flex DataGrid reads a field from lastResult.node as number

    - by Nemi
    Why Flex 3 DataGrid reads a string from XML lastResult.node as number? A field is saved as var_char in mysql, php reads it as string and pass it OK. If there are more then 16 charaters it gets rounded.... For example: this in database cell: 12345678901234567 gets read in DataGrid as nubmer as 12345678901234568 this is in database cell: 5555544444222223333377777 php reads it same and puts it in XML flex reads XML into arrayCollection and DataGrid reads it as: 5.55554444422222e+24 So it reads it as number, why? And how to make it read as String? I tried with labelFunction, no help.

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  • DBCC CHECKDB WITH DATA_PURITY gives out of range error

    - by Mark Allison
    Hi there, I have restore a SQL Server 2000 database onto SQL Server 2005 and then run DBCC CHECKDB WITH DATA_PURITY and I get this error: Msg 2570, Level 16, State 3, Line 2 Page (1:19558), slot 13 in object ID 181575685, index ID 1, partition ID 293374720802816, alloc unit ID 11899744092160 (type "In-row data"). Column "NumberOfShares" value is out of range for data type "numeric". Update column to a legal value. The column NumberOfShares is a numeric (19,6) data type. If I run the following select max (NumberOfShares) from AUDIT_Table select min (NumberOfShares) from AUDIT_Table I get: 22678647.839110 -1845953000.000000 These values are inside the bounds of a numeric (19,6) so I'm not sure why the DBCC check fails. Any ideas to find out why it fails? Do I need to use DBCC PAGE? How would you troubleshoot this? Thanks, Mark.

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  • Can not get json response using $.getJSON

    - by Mellon
    I am currently developing a Ruby on rails 3 application. My server controller function render a json object as response: class DaysController < BaseController ... def the_days ... render :json => days end end In my javascript,I use the following code to get json response from server( that's from the_day function in controller) $.getJSON( url, {emp_id: emp_id}, function(data) { var result = data.response; alert(result) alert(data) }, "json" ); I use firefox browswer and checked with Firebug, in Firebug Net-XHR, I see the Get request is successful, and the response "days" is there. That's both request and response are successful. But I did not see the two alert window defined in the above $.getJSON function, why? Why I can not get the response "days" in $.getJSON function??

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