copy of w9

16. Shallow copy and deep copy in python, 16. python copy Before talking about what is a copy of depth, let's look at this phenomenon: a = ['scolia', 123, [], ]b = a[:]b[2].append(666)print aprint b Why does it affect a if I only modify B? I have read it in my previous article and said: memory references are stored in

In Python, an object assignment is actually a reference to an object. When you create an object and then assign it to another variable, Python does not copy the object, but only copies the reference to the object.There are generally three ways toalist=[1,2,3,["a","b"]](1) Direct assignment, passing the reference of the object, the original list is changed, and the assigned B will make the same change.>>> b=list>>> Print B[1, 2, 3, [' A ', ' B ']]>>> L

Write in front:. Copy () copies and [:] copies in Python are shallow copiesIn Python, an object assignment is actually a reference to an object. When you create an object and then assign it to another variable, Python does not copy the object, but only copies the reference to the object.There are generally three ways toeg:alist=[1,2,3,["a","b"]](1) Direct assignment, passing the reference of the object, the

First of all, I need to say: In a controller, I have a mutable custom model array, I want to jump to the B controller for editing, I pass in the model array. In the B controller I make edits, and then save the edited array back to the reverse passAt first, did not think what was wrong, and later found in the B controller as long as I changed the original data, even if not click Save, but directly pop off the B controller returned a controller, my model data will be changed, because I am in the e

Today I read a few of the Python copy of the blog, I do not feel very clear, so I do experiments on their own, hereby recorded.A copy is said for a composite object, such as a list, a class, etc., while a variable of a number, a string, is not a copy.The implementation copies are:1. Factory functions2. Slicing operations3. The Copy method of the objectCopy method

It was all about remembering to keep copy and strong and asking me. I don't know what I'm talking about.Verify with simple code. Sometimes it takes a little time to verify that you can make your ideas clearer.nsmutablestring * mustr = [nsmutablestring stringwithstring:@ "good"]; Self . str = mustr; Self . fuzhistring = mustr; NSLog(@ "Self.str is (%@) = = = Str,self.fuzhistring is (%@)", self. Str,self. Fuzhistring); NSLog(@ "Self.str *p

The original file path is fileoldpath;New file path: filenewpath,Then you can useFile. Move (fileoldpath, filenewpath)Or file. Copy (fileoldpath, filenewpath)Note that the path here is the folder path + file name, which can be implemented using path. Combine (). C # copy a folder The Directory class contains the createdirectory, move, and delete methods, but there is no

Add the copyright notice code to the js copy content, and copy the copyright notice code to the js copy 1 $ ("body "). on ('copy', function (e) {if (typeof window. getSelection = "undefined") return; // IE8 or earlier... var body_element = document. getElementsByTagName ('body') [0]; var selection = window. getSelectio

DOCTYPE HTML>HTMLLang= "en">Head> MetaCharSet= "UTF-8"> Metaname= "Viewport"content= "Width=device-width, initial-scale=1.0"> Metahttp-equiv= "X-ua-compatible"content= "Ie=edge"> title>Documenttitle>Head>Body> Scripttype= "Text/javascript"> functionCopyUrl2 () {varUrl2=document.getElementById ("Biao1"); Url2.select (); //Select ObjectDocument.execcommand ("Copy"); //perform a browser copy commandAle

Win7 with u disk copy file hint "Copy file too large cannot copy" how to resolve Operation Steps: 1, the U disk into the computer USB interface; 2, press Win+r key, open run, enter cmd, click OK; 3. In the Open Command Prompt window, enter convert x:/fs:ntfs (X represents the disk character of the U disk), and return. 4, the setup is complete,

[MySQL] Replication (3)-Create master-slave replication (replication from another server) bitsCN.com In the previous article, the creation of master-slave replication assumes that the master-slave databases are all the databases that have just been installed, that is to say, the data on the two servers is the same. this is not a typical case, in most cases, there is a master database that has been running for a period of time, and then synchronize it with a newly installed Slave Database. This a

next ~ on the finish ~ boil and boil--------------------------------------------------------------------------------------------------------------- --------------------------------------------Then we open the publisher's Replication Monitor to see ~Good ~ normal ~If there is anything abnormal ~ look at what agent Ah ~ such as there is no normal workAlso, for snapshot replication, the publisher's job can set the frequency of execution and how often it is set to run. Yes, roughly.Learn from 0

Http://blog.csdn.net/xdrt81y/article/details/24331103Before reading this article, I first want to know the differences between copy and retain. If there are any errors, I hope you can give me more advice: Differences between copy and retain: Copy is to create a new object, retain is to create a pointer, reference object count plus 1. The

(If you encounter the problem of deep copy and shortest copy during encoding today, find this article online and repost it by: Yangchen.) before reading this article, first understand the differences between copy and retain, if there are any errors, please kindly advise: Differences between copy and retain:

Before reading this article, I first want to know the differences between copy and retain. If there are any errors, I hope you can give me more advice: Differences between copy and retain: Copy is to create a new object, retain is to create a pointer, reference object count plus 1. The Copy attribute indicates that the

iOS provides a copy and Mutablecopy method, as the name suggests, copy is a copy of a Imutable object, and Mutablecopy is a copy of a mutable object. The difference between copy and retain: Copy is to create a new object, retain

Basic JavaScript method of deep copy (shallow copy and deep copy), javascript depth Preface When it comes to deep copy, we must first mention the JavaScript data type. In the previous article, the basic JavaScript method-the data type is very clear, so I will not talk about it here. You need to know that JavaScript dat

In fact, the distinction between a shallow copy copy () and a deep copy of Deepcopy () must relate to how Python stores the data. First straight to the conclusion: -Our normal replication is the deep copy, which will be copied completely again as a separate new individual exists. Therefore, changing the or

For normal types of objects, replication between them is simple, for example:int a=88;int b=a;And the class object is different from ordinary object, the inner structure of class object is generally more complex, there are various member variables. Let's look at a simple example of a class object copy.#include using namespace Std;Class Cexample{Privateint A;Publiccexample (int b){a=b;}void Show (){cout}};int main (){Cexample A (100);Cexample B=a;B.sho

For normal types of objects, replication between them is simple, for example:int a=88;int b=a;And the class object is different from ordinary object, the inner structure of class object is generally more complex, there are various member variables. Let's look at a simple example of a class object copy.iostream>UsingNamespaceStdClassCexample{Private:IntAPublic:Cexample (Intb{A=b;}voidShow (){coutaENDL; } }; intmain () { cexamplea ( 100); cexampleb=A; b.show (); return0; } NBSP;