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Questions tagged [shallow-copy]

A shallow copy of an object is a duplicate that may not be fully independent of the original, in the sense that any references / pointers it holds to other objects refer to the same objects that the original's do. Use this tag for questions regarding implementing or using shallow copying methods.

Shallow copying is a process by which an object is duplicated to create a copy that may not be wholly independent of the original. Also known as "field by field" copying, this differs from deep copying with respect to the treatment of references / pointers to other objects: shallow copying copies the references / pointers held by the original, whereas deep copying makes a deep copy of each referenced object, too. Shallow copying is "shallow" in the sense that it copies only the original object itself, not any appearing deeper in its reference graph.

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394 questions
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when would I use a shallow copy?

I understand what the difference between a shallow and deep copy are, but I really don't understand in what situations a shallow copy would be preferred. If I'm not mistaken, shallow copy makes a new copy of the value types and simply copies the…
David Torrey
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Is shallow copy sufficient for structures with char[]?

I have a structure containing character arrays with no any other member functions. I am doing assignment operation between two instances of these structures. If I'm not mistaken, it is doing shallow copy. Is shallow copy safe in this case? I've…
jasonline
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Deep Copy Constructor for binary tree

I am trying to create a deep copy of my binary tree data structure in C++. The problem is the code I am using only seems to be giving me a shallow copy (which seems to cause problems with my deconstructor). the code below is my binary tree copy…
brian4342
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Does Spread Syntax create a shallow copy or a deep copy?

I am extremely confused for days now regarding the true definition of a shallow copy and a deep copy. When I read the mdn docs (https://developer.mozilla.org/en-US/docs/Glossary/Shallow_copy) on shallow copy, it all made sense. The first paragraph…
espc
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Is vector::push_back() making a shallow copy & how to solve this

In the program I am writing, I have something similar to the code here: #include #include #include using namespace std; struct people { string name; int st; int sn[50]; }; int main() { unsigned int…
zw324
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Java: Why String is special in Deep Copy and Shallow copy?

These days I am learning the clone method of Java. I learned that clone uses shallow copy. If I want to implement a deep copy of an object, then I should follow the following principles from this website No need to separately copy primitives. All…
chenlangping
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shallow copy in python

I am a little confused on how shallow copy works, my understanding is when we do new_obj = copy.copy(mutable_obj) a new object is created with elements of it still pointing to the old object. Example of where I am confused - ## assignment i = [1, 2,…
Ani Menon
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Does module.exports in node js create a shallow copy or deep copy of the exported objects or functions?

For example, If I have 2 modules try1.js and try2.js try1.js module.exports.msg = "hello world"; try2.js try1 = require('./try1'); try1.msg = "changed message"; Does the change in the contents of msg made in try2.js affect try value of…
Ullas Kashyap
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System.arraycopy() shallow copy or deepcopy with primitive and object references

I read somewhere that System.arraycopy does create a new copy for primitive data types and shallow copy for object references. so, that I started the experiment that with below code //trying with primitive values int a[] ={1,2,3}; int b[] = new…
gajapathy p
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What is the difference between MemberwiseClone() and Assigning a Reference type in C#?

If i have a code like this class Student { public string RollID { get; set; } } class Person { public Student student { get; set; } public string Address { get; set; } public string Name { get; set; } public Person Clone() …
Lijin Durairaj
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How can I create a deep copy of my list collection

Suppose I have the following class: public class Author { public int ID {get; private set;} public string firstName {get; private set;} public string lastName {get; private set; } public Author(int id, string firstname, string…
user6029770
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Angular.copy() not deep copying referenced arrays

In my Angular application, I have an array that refers to the coordinates of a polygon. Eg: [[-1,0], [0,1], [1,0], [0,-1], [-1,0]] The important bit here is that the that the first and last points are repeated, and actually reference the same…
Will Durney
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How do I create a shallow copy of an IEnumerable?

I have an IEnumerable object as: IEnumerable listSelectedItems; Which contains three items. Now i created a new object and want to get all items from listSelectedItems, so i wrote this code: IEnumerable newList =…
Murtaza Munshi
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How to create an instance of a value type "by reference"

Consider the code and output: using Microsoft.Xna.Framework; //Where color is from ^ that static Color color = new Color(0, 0, 0, 0); static void Main(string[] args) { Color otherColor = color; color.B = 100; …
Colton
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Shallow copy: why is list changing but not a string?

I understand that when you do a shallow copy of a dictionary, you actually make a copy of the references. So if I do this: x={'key':['a','b','c']} y=x.copy() So the reference of the list ['a','b','c'] is copied into y. Whenever I change the list (…
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