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Catalog js precise calculation js precise calculation var numA = 0.1; var numB = 0.2; alert( numA + numB ); 0.1 + 0.2 = 0.30000000000000004. Problem of calculation accuracy error (related to binary). Almost all programming languages have similar precision errors for the four-way operation of floating-point numbe ...

Detailed explanation of deep copy and shallow copy in python Summary In python's syntax, there are two ways to copy variables One is deep copy, the other is shallow copy Let's start with the deep copy grammar Here, you need to import the deep copy in the copy module of the system import copy New object = copy.deep copy (copied object) explain ...

Vue Day 02 Article directory Vue Day 02 1, ES6 syntax supplement 1.1.let/var (define variable) 1.2.const 1.3. Object enhanced writing 2, Event monitoring 3, Condition judgment 3.1.1. Introduction to if basic syntax 3.1.2. case 3.1.3. Use of v-show 4, Loop traversal 4.1.1. Loop through array 4. ...

The second week, today we will talk about the use of Logstash. First, we open ES, use postman to create a new index user, and use PUT mode in postman to send requests to localhost:9200/user. See the return information: {     "acknowledged": true,     "shards_acknowledged": true,     "index": "user" } This indicates that the index was est ...

1, The basis of object-oriented programming 1.1 object oriented programming (1) What is object-oriented programming In C language, the designed application program is too single, because all the functions are contained in several or even one code block, which can only serve a single program. There ...

Spring Boot uses Aop for log global interception 1 New Spring Boot Project Introducing aop dependency in 2 Pom 3Write processing code 3.1 Procedure Principle and Process 3.2 Custom Log Comment@log 3.3 Define IndexController for Testing 3.4 Define the aop class LogAspect and WebLogAspect 3.5 Test ...

Scenario: there is a server with IIS architecture. I want to know how one js (index.js) is called by other websites every day. First, Download all the IIS log schema a TP6.0 program and put it into the runtime/log folder. public function checkIndexJs() { $file = root_path() . DIRECTORY_SEPARATOR . 'runtime' . DIRECTORY_SEPARATOR ...

1. Introduction to iterator In order to improve the efficiency of C + + programming, STL (Standard Template Library) provides many containers, including vector, list, map, set, etc. However, some containers (vectors) can access the data in the container by subscript index, but most containers (list, map, set) cannot access the elements in the c ...

tcpdump tcpdump is a necessary tool in debugging network communication program. tcpdump is very powerful, you can see every detail of network communication. For example, TCP can see 3 handshakes, PUSH/ACK data push, close 4 waves, all details. Including the number of bytes and time of each network packet reception. Usage method The simplest exa ...

Functional interface Functional interface 1.1 overview If there is only one method in an interface, and the default attribute of the method is public abstract method, the interface can be called a functional interface. 1.2 use @ functional interface Be similar to @Override Turn on code rewrite forma ...