deep-copy

问题 I'm trying to implement deep copy functionality using Doctrine 2, and I almost have it except for a method on one of my entities that attempts to strip out certain records from an association before returning the collection. The problem is that when I call getRoofAreas() below, I get an array of Proxy objects, which my deep copy code doesn't like: /** * @OneToMany(targetEntity="\Entities\QuotingRoofAreas", mappedBy="customerId", cascade={"persist"}) * @OrderBy({"areaIndex" = "ASC"}) */

问题 So I have a printing component that serves a Silverlight application. Other modules in this program have the ability to signal the printing component and pass it a UIElement , which the printing component will then draw to the screen. All well and good. The problem arises when I try to manipulate the UI Element in order to better format it to fit the user's selected paper size or anything to that effect; it seems that the UI element that is passed in is frequently the exact same instance of

问题 This should be a pretty basic question, but I've been having a little trouble finding a definite answer. When you have an array of values and you use the .ToArray() method does it create a deep or shallow copy of the array? 回答1: No. You can easily verify this by writing a small program to test. 来源： https://stackoverflow.com/questions/10387415/in-c-sharp-does-array-toarray-perform-a-deep-copy

问题 I have two classes: a parent class and a container class. The parent class instance has matching container class instance as a weak reference. There is a problem while deep copying the parent instance, the weakref is still linking to the original instance. Here is a minimal example: import weakref from copy import deepcopy class Container: def __init__(self, parent): self.parent = weakref.ref(parent) class Parent: def __init__(self): self.container = Container(self) if __name__ == '__main__':

问题 Generally speaking, what is the correct way to deep copy Qt containers? I'm not worried about deep copying the containers recursively, although addressing such would be helpful. 回答1: Despite what everyone will tell you - that you don't deep copy Qt containers - there are situations in which you simply need to perform an actual deep copy instead of just a shallow one. To do that, use detach() : container1 = container2; container1.detach(); 来源： https://stackoverflow.com/questions/16800206/how

问题 I wonder if i misunderstood something: does a copy constructor from std::string not copy its content? string str1 = "Hello World"; string str2(str1); if(str1.c_str() == str2.c_str()) // Same pointers! printf ("You will get into the IPC hell very soon!!"); This will print "You will get into the IPC hell very soon!!" and it annoys me. Is this the normal behavior of std::string ? I read somewhere that it usually does a deep copy. However, this works as expected: string str3(str1.c_str()); if

问题 Does Perl 6 have a built-in tool to make a deep copy of a nested data structure? Added example: my %hash_A = ( a => { aa => [ 1, 2, 3, 4, 5 ], bb => { aaa => 1, bbb => 2 }, }, ); my %hash_B = %hash_A; #my %hash_B = %hash_A.clone; # same result %hash_B<a><aa>[2] = 735; say %hash_A<a><aa>[2]; # says "735" but would like get "3" 回答1: my %A = ( a => { aa => [ 1, 2, 3, 4, 5 ], bb => { aaa => 1, bbb => 2 }, }, ); my %B = %A.deepmap(-> $c is copy {$c}); # make sure we get a new container instead of

问题 If all the objects within the bean implement Serializable interface, will BeanUtils.cloneBean() do a deep copy? 回答1: No, cloneBean() does shallow copy only. If you want deep copy. You may refer this link which has technique to do deep copy. 回答2: Use SerializationUtils.clone method from the Apache Commons Lang for the deep copy . It copies the entire class hierarchy. SerializationUtils.clone(object); 回答3: There is also another java library which supports both shallow cloning and deep cloning.

问题 I have the following problem: I have a class which should do this: Obj o; Obj o1(o), o1=o; // deep-copies const Obj c(o), c=o; // deep-copies const Obj c1(c), c1=c; // shallow-copies Obj o2(c), o2=c; // deep-copies How can I do this preferably without inheritance? (I mean I would do Const_obj inheriting from Obj otherwise.) EDIT: Using o.clone() directly is not an option because then I could easily introduce bugs by accidentally not cloning. EDIT: Finally, there is a proper, complete solution

问题 I'm implementing a templated vector class (not the data container, but the vector in the linear algebra sense), and I'm getting quite a few errors whenever I refer to rhs in my operator overloading. Also, my copy constructor doesn't seem to be working. #ifndef __VecXd__VecXd__ #define __VecXd__VecXd__ #define ULL unsigned long long #include <iostream> using namespace std; template <class T> class VecXd { public: explicit VecXd(ULL newDimension = 1) { dimension = newDimension; vector = new T