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  • JQuery and JSON - Add element

    - by Villager
    Hello, I have a JSON variable defined as: var myCollection = { "data": [ { "name":"Joe", "id":"1" }, { "name":"Bill", "id":"2" }, { "name":"Dave", "id":"3" } ] }; I have a JavaScript function that is responsible for adding items to the data element in myCollection. However, I'm not sure how to add a name/id pair to the collection via JavaScript. Can someone show me how to add to a JSON collection via JavaScript? Thank you!

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  • Java replacement for C macros

    - by thkala
    Recently I refactored the code of a 3rd party hash function from C++ to C. The process was relatively painless, with only a few changes of note. Now I want to write the same function in Java and I came upon a slight issue. In the C/C++ code there is a C preprocessor macro that takes a few integer variables names as arguments and performs a bunch of bitwise operations with their contents and a few constants. That macro is used in several different places, therefore its presence avoids a fair bit of code duplication. In Java, however, there is no equivalent for the C preprocessor. There is also no way to affect any basic type passed as an argument to a method - even autoboxing produces immutable objects. Coupled with the fact that Java methods return a single value, I can't seem to find a simple way to rewrite the macro. Avenues that I considered: Expand the macro by hand everywhere: It would work, but the code duplication could make things interesting in the long run. Write a method that returns an array: This would also work, but it would repeatedly result into code like this: long tmp[] = bitops(k, l, m, x, y, z); k = tmp[0]; l = tmp[1]; m = tmp[2]; x = tmp[3]; y = tmp[4]; z = tmp[5]; Write a method that takes an array as an argument: This would mean that all variable names would be reduced to array element references - it would be rather hard to keep track of which index corresponds to which variable. Create a separate class e.g. State with public fields of the appropriate type and use that as an argument to a method: This is my current solution. It allows the method to alter the variables, while still keeping their names. It has the disadvantage, however, that the State class will get more and more complex, as more macros and variables are added, in order to avoid copying values back and forth among different State objects. How would you rewrite such a C macro in Java? Is there a more appropriate way to deal with this, using the facilities provided by the standard Java 6 Development Kit (i.e. without 3rd party libraries or a separate preprocessor)?

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  • question related to backbutton of UIToolbar

    - by user217572
    sir I'm getting 2 different values in back button click My question is, *If I want to back to view as per my value coming in int variable. how is it possible? *My second question is that my project is based on UINavigationController So,how should i do that? bcoz i'm using PushviewController to puch the new view from olderview Thanks in advance

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  • What is the rationale to not allow overloading of C++ conversions operator with non-member function

    - by Vicente Botet Escriba
    C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From > operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration> operator boost::posix_time::ptime( const boost::chrono::time_point<Clock, Duration>& from) { using namespace boost; typedef chrono::time_point<Clock, Duration> time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast<duration_t>( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast<long>(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. For a more complete description of the problem, see here or on my Boost.Conversion library.. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

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  • How to distinguish between <expr> and non-<expr> mappings?

    - by ZyX
    I want to add a possibility of restoring mappings overwritten by my plugin. But the problem is that I cannot distinguish between the following mappings: inoremap <expr> @ test and inoremap @ test First mapping inserts the contents of the variable test, while second inserts text «test». Both mappings give maparg("@", 'i')=="test" and identical output of inoremap i.

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  • Rails 3: How to validate that A < B where A and B are both model attributes ?

    - by Misha Moroshko
    I would like to validate that customer_price >= my_price. I tried the following: class Product < ActiveRecord::Base attr_accessor :my_price validates_numericality_of :customer_price, :greater_than_or_equal_to => my_price ... end (customer_price is a column in the Products table in the database, while my_price isn't.) Here is the result: NameError in ProductsController#index undefined local variable or method `my_price' for #<Class:0x313b648> What is the right way to do this in Rails 3 ?

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  • C++: defining maximum/minimum limits for a class

    - by Luis
    Basically what the title says... I have created a class that models time slots in a variable-granularity daily schedule (where for example the first time slot is 30 minutes, but the second time slot can be 40 minutes); the first available slot starts at (a value comparable to) 1. What I want to do now is to define somehow the maximum and minimum allowable values that this class takes and I have two practical questions in order to do so: 1.- does it make sense to define absolute minimum and maximum in such a way for a custom class? Or better, does it suffice that a value always compares as lower-than any other possible value of the type, given the class's defined relational operators, to be defined the min? (and analogusly for the max) 2.- assuming the previous question has an answer modeled after "yes" (or "yes but ..."), how do I define such max/min? I know that there is std::numeric_limits<> but from what I read it is intended for "numeric types". Do I interpret that as meaning "represented as a number" or can I make a broader assumption like "represented with numbers" or "having a correspondence to integers"? After all, it would make sense to define the minimum and maximum for a date class, and maybe for a dictionary class, but numeric_limits may not be intended for those uses (I don't have much experience with it). Plus, numeric_limits has a lot of extra members and information that I don't know what to make with. If I don't use numeric_limits, what other well-known / widely-used mechanism does C++ offer to indicate the available range of values for a class?

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  • Extending existing data structure in Scala.

    - by Lukasz Lew
    I have a normal tree defined in Scala. sealed abstract class Tree case class Node (...) extends Tree case class Leaf (...) extends Tree Now I want to add a member variable to all nodes and leaves in the tree. Is it possible with extend keyword or do I have to modify the tree classes by adding [T]?

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  • jquery - Getting the second level parent of an element

    - by j-man86
    I am trying to retrieve the parent of an element's parent (grandparent?). I want to find that grandparent, then find a tag in that element, then store that text as a variable to publish elsewhere on the page. I've been trying to use the parent() function but without success. Here's the code I tried: $('.mixPlayCell a').click( function() { var title = $(this).parent().get(0).parent().get(0).text(); alert(title); }); Thanks!

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  • jQuery grab html

    - by Happy
    We have link to some page (with html code, on the same domain), that page have one img, which attributes title and alt are equal. Script must open link (no showing on the page), grab the src attribute of img which title=alt, and throw the value into some variable. Is it possible to do? Thanks.

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  • How do I get the file size of a large (> 4 GB) file?

    - by endeavormac
    How can I get the file size of a file in C when the file size is greater than 4gb? ftell returns a 4 byte signed long, limiting it to two bytes. stat has a variable of type off_t which is also 4 bytes (not sure of sign), so at most it can tell me the size of a 4gb file. What if the file is larger than 4 gb?

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  • When are static class variables initialized during runtime?

    - by Jake
    Hi, I have the following: class Thing { static Thing PREDEFINED; type _private; Thing() { _private = initial_val; } } Thing Thing::PREDEFINED = redefined_val; in global scope, i have this Thing mything = Thing::PREDEFINED; but it does not have the desired effect. mything is still initial_value and there were no errors too. So, may I ask when is the static class variable initialized during runtime?

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  • How to initialize List<E> in empty class constructor?

    - by Nazgulled
    Hi, The following code obviously doesn't work because List<E> is abstract: public class MyList { private List<E> list; public MyList() { this.list = new List<E>(); } } How can I initialize MyList class with an empty constructor if I need the list variable to be a LinkedList or a ArrayList depending on my needs?

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  • Problem porting boost 1.33.1 programm to boost 1.42.0

    - by Volker Beyer
    i've got a variable: boost::program_options::options_description m_corbaDesc; and the following is done with it m_corbaDesc.add_options() ("corba", boost::programm_options::parameter("<options+>", &m_corbaOptions), "CORBA -ORBInitRef options") ("corba-ns", boost::program_options::parameter("<name:port>", &m_corbaNameService), "simple-type CORBA NameService").default_value("localhost:12345") ; this works in boost boost 1.33.1 but not in 1.42.0. What would it be in 1.42.0?

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  • What .NET serializers have fixed size output for a given class?

    - by Jader Dias
    XML based serializers have variable size output for a given class. I can't use them to append data to my Memcached list, since I won't be able to retrieve that information later. But if I knew my serializer produced a fixed size output (N bytes), I could retrieve my data by splitting my list in N bytes chunks and then deserializing those chunks individually. I have created my own serializer for my class, but what other serializers I could use?

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  • gcc optimization? bug? and its practial implication to project

    - by kumar_m_kiran
    Hi All, My questions are divided into three parts Question 1 Consider the below code, #include <iostream> using namespace std; int main( int argc, char *argv[]) { const int v = 50; int i = 0X7FFFFFFF; cout<<(i + v)<<endl; if ( i + v < i ) { cout<<"Number is negative"<<endl; } else { cout<<"Number is positive"<<endl; } return 0; } No specific compiler optimisation options are used or the O's flag is used. It is basic compilation command g++ -o test main.cpp is used to form the executable. The seemingly very simple code, has odd behaviour in SUSE 64 bit OS, gcc version 4.1.2. The expected output is "Number is negative", instead only in SUSE 64 bit OS, the output would be "Number is positive". After some amount of analysis and doing a 'disass' of the code, I find that the compiler optimises in the below format - Since i is same on both sides of comparison, it cannot be changed in the same expression, remove 'i' from the equation. Now, the comparison leads to if ( v < 0 ), where v is a constant positive, So during compilation itself, the else part cout function address is added to the register. No cmp/jmp instructions can be found. I see that the behaviour is only in gcc 4.1.2 SUSE 10. When tried in AIX 5.1/5.3 and HP IA64, the result is as expected. Is the above optimisation valid? Or, is using the overflow mechanism for int not a valid use case? Question 2 Now when I change the conditional statement from if (i + v < i) to if ( (i + v) < i ) even then, the behaviour is same, this atleast I would personally disagree, since additional braces are provided, I expect the compiler to create a temporary built-in type variable and them compare, thus nullify the optimisation. Question 3 Suppose I have a huge code base, an I migrate my compiler version, such bug/optimisation can cause havoc in my system behaviour. Ofcourse from business perspective, it is very ineffective to test all lines of code again just because of compiler upgradation. I think for all practical purpose, these kinds of error are very difficult to catch (during upgradation) and invariably will be leaked to production site. Can anyone suggest any possible way to ensure to ensure that these kind of bug/optimization does not have any impact on my existing system/code base? PS : When the const for v is removed from the code, then optimization is not done by the compiler. I believe, it is perfectly fine to use overflow mechanism to find if the variable is from MAX - 50 value (in my case).

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  • javascript instanceof get type from string name

    - by dcp
    Let's say I have this (assume the name variable is "receiver"): if (!(receiver instanceof com.HTMLReceiver)) { throw new com.IllegalArgumentException( name + " is not an instance of com.HTMLReceiver."); } I'd like to factor this code out into a common method so I could call it like this: Helper.checkInstance(receiver, "com.HTMLReceiver"); But I don't know of a way to convert the com.HTMLReceiver from a string to its actual type so I can use instanceof on it. Is there a way?

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  • How to generate changelog: git log since last Hudson build?

    - by takeshin
    I'm using Phing to do post build tasks in Hudson. I want to generate changelog containing all commits since last successful Hudson build. But looks like neither Hudson nor Git plugin for Hudson does not provide %last_build_time% variable. This would be satisfying solution, (but how to get the time?): git log --pretty="%s" --since="%last_build_time%" The only way I see for now is extracting it from the job xml file, but I do not know if it is possible with Phing. How do you generate your change logs?

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  • Fastest way to clamp a real (fixed/floating point) value?

    - by Niklas
    Hi, Is there a more efficient way to clamp real numbers than using if statements or ternary operators? I want to do this both for doubles and for a 32-bit fixpoint implementation (16.16). I'm not asking for code that can handle both cases; they will be handled in separate functions. Obviously, I can do something like: double clampedA; double a = calculate(); clampedA = a > MY_MAX ? MY_MAX : a; clampedA = a < MY_MIN ? MY_MIN : a; or double a = calculate(); double clampedA = a; if(clampedA > MY_MAX) clampedA = MY_MAX; else if(clampedA < MY_MIN) clampedA = MY_MIN; The fixpoint version would use functions/macros for comparisons. This is done in a performance-critical part of the code, so I'm looking for an as efficient way to do it as possible (which I suspect would involve bit-manipulation) EDIT: It has to be standard/portable C, platform-specific functionality is not of any interest here. Also, MY_MIN and MY_MAX are the same type as the value I want clamped (doubles in the examples above).

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