Coder Life - Birost

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Introduction to Linux-Introduction to Shell Programming-Suitable for Xiaobai

One, the use of variables 1. Variable naming When defining a variable, do not add a dollar sign to the variable name ($, required for variables in the PHP language), such as: your_name= "yikoulinux" Copy code Note that there can be no spaces between the variable name and the equal sign, which may be different from all programming languages you are familiar with. At the same time, the naming of variable names must follow the following rules: Only English letters, numbers and underscores can be u

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[macOS translation] The command line program tutorial on macOS

Original address: www.raywenderlich.com/511-command... Original author: www.raywenderlich.com/u/ericwasta... Release time: July 21, 2017-Article (30 minutes)-Beginner Through this command line program tutorial on macOS, discover how easy it is to make your own terminal-based application. Updated for Xcode 9 and Swift 4! 7/21/17 update: This command line program tutorial on macOS has been updated for Xcode 9 and Swift 4. The typical Mac user uses a graphical user interface (GUI) to interact with

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Java Object Oriented

The first section object-oriented 1. Class and Object Concept of class and object A class is a class of things with the same attributes and behaviors. An object refers to an actual individual in a class. For example, an animal is a class, and a puppy is a single individual belonging to an animal, that is, an object In Java, the syntax for instantiating an object from a class is as follows: Class name object = new class name(); For example: Student stu = new Student(); copy the code Member attrib

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Pandas basic operation guide-2 days to learn pandas

Author: Guangcheng Pandas is a tool based on NumPy, which was created to solve data analysis tasks. Pandas incorporates a large number of libraries and some standard data models, providing the tools needed to efficiently manipulate large data sets. Pandas provides a large number of functions and methods that enable us to process data quickly and easily. You will soon discover that it is one of the important factors that make Python a powerful and efficient data analysis environment. This articl

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Steps for Creating an LLVM Backend

Steps for Creating an LLVM Backend Table of Contents 1. Register a new LLVM Backend. 2. Setup Target machine structures. 2.1. classes 2.2. Target Description files (.td) 2.3. Afterward: 3. Setup MC Layer 3.1. MC Layer: MC Project 3.2. classes 3.3. Afterward: 4. Setup Asm Parser: 4.1. classes: 4.2. Afterward: 5. Setup Disassembler: 5.1. classes: 5.2. Afterward: This aritcle is to show the steps for creating an LLVM Backend. 1 Register a new LLVM Backend. Details in LLVM Target Registration Minim

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epoll complete example

Article source: www.cppblog.com/API/archive... #include <deque> #include <map> #include <vector> #include <pthread.h> #include <semaphore.h> #include <time.h> #include <sys / time.h> #include <sys / shm.h> #include <errno.h> #include <sys / types.h> #include <fcntl.h> #include <stdio.h> #include <string> #include <cstdio> #include <unistd.h > #include <signal.h> #include <sys / types.h> #include

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[Optimization] based on MATLAB GUI simulated annealing algorithm regional communication network frequency planning [including Matlab source code 933]

1. Introduction Introduction to Simulated Annealing Algorithm 3 Parameters of Simulated Annealing Algorithm Simulated annealing is an optimization algorithm. It cannot exist independently. It needs an application. Temperature is the parameter that needs to be optimized for simulated annealing. If it is applied to cluster analysis , Then it means that one or several parameters need to be optimized in cluster analysis, and this parameter or parameter set is represented by temperature. It can be a

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It took a month to sort out and summarize the core architecture of 4D microservices. It turned out to be not as difficult as you think...

I studied in the company for nearly a month. Within a month, I started to get in touch with the distributed microservice architecture from 0, which gave me a lot of gains. Today, I will sort out the core content of the microservice architecture (all dry goods) from start to finish. Below, you will see the core principles of mainstream microservice frameworks in the industry, including a brief introduction to service discovery, gateways, configuration centers, monitoring and other components, fun

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Data structure analysis-TAILQ_QUEUE queue

blog.csdn.net/luotuo44/ar...  There is a queue.h file in the Libevent source code, located in the compat/sys directory. Five data structures are defined in this file, of which TAILQ_QUEUE is the most extensive. This article will talk about this data structure. Queue structure: TAILQ_QUEUE consists of the following two structures to work together. #define TAILQ_HEAD(name, type) \ struct name {\ struct type *tqh_first; /* first element */ \ struct type **tqh_last; /* addr of last next element

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Implementation of high concurrency server under linux (modify the limit of the number of open files in the user process ulimit -n)

Terminal command: netstat -nalp|grep 8011|wc -l #View the number of client connections on port 8011\ ulimit -n 102400 #Modify the maximum number of files in the current process\ \ Experience shared by netizens: #Modify the file /etc/sysctl.conf and append these words at the end fs.file-max = 2097152  fs.nr_open = 2097152  net.core.somaxconn = 65535  net.core.rmem_default = 65535  net.core.wmem_default = 65535  net. core.rmem_max = 8388608  net.core.wmem_max = 838860

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spring-framework-core-iocContainer

Reading notes Instantiate bean Instantiate bean in xml mode Instantiate bean by annotation Instantiate beans in java ClassPathXmlApplication and AnnotationConfigApplicationContext Where are the Beans stored? Which method is appropriate? the name of the bean Default name Set name Set alias Lazy loading bean loading order bean scope Bean callback function Component scan @Component @Controller @Service@Configuration @Bean @Configuration condensed mode and full mode Turn on component scanning Defau

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The most comprehensive network: all kinds of resource websites are organized for you! All you want is here

Before, many friends asked me if there are any useful and efficient online tools to share in my daily work, study, development, blogging, and video making. It just so happens that this time I will take this opportunity to share a wave. Not surprisingly, it is another sharing for the family. Remember to like/read it, don t just stare at it. Friends are also welcome to share and Amway s tools that you find useful, remember to share good things. The article is organized from: WeChat public account

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Python thread creation and parameter transfer-Python zero-based introductory tutorial

table of Contents 1. Python thread explanation 2. Python thread creation and start 1. Import the thread module 2. Create a thread and initialize the thread 3. Start the thread Three. Python thread parameter transfer Four. Python thread ends V. Introduction to Python thread related functions Six. Python thread key summary Seven. Guess you like it Zero-based Python learning route recommendation: Python Learning Directory >> Introduction to Python Basics Although we have not introduced the co

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Start from scratch, use Webpack to build React basic tutorials

20170315 update Since webpack has been updated to version 2.0, many configuration items have been changed, so some items in this article may be out of date It is recommended that you use the official facebook build tool facebookincubator/ create - react -app to create a basic React project Because the configuration of webpack is too complicated, we don't need to understand it all, it is just a tool, and maybe it will become another tool someday. What really needs to be understood is its principl

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LiteOS kernel source code analysis: message queue Queue

Abstract: This article analyzes the source code of the LiteOS queue module to grasp the difference in queue usage. This article is shared from the Huawei Cloud Community " LiteOS Kernel Source Code Analysis Series Ten Message Queue Queue ", the original author: zhushy. Queue is a data structure commonly used for communication between tasks. The task can read messages from the queue. When the message in the queue is empty, the reading task is suspended; when there is a new message in the queue,

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Leetcode interview questions 16.06. Minimum difference

Links to Likou Questions Solution step description Sort the two arrays first Minimize the interval to be traversed Double pointer traversal calculation result You can think of two arrays as two intervals on the integer number axis (each is a discrete interval defined by the maximum and minimum of the array, but you can think of them as continuous intervals or line segments). By analyzing the positional relationship between these two intervals, the process of "reducing the interval to be traverse

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Detailed explanation of @property in Objective-C (retain means pointer copy, copy means content copy, firecat recommended )

Article source: www.cnblogs.com/andyque/arc... @property and @synthesize appear in pairs, which can automatically generate access methods for a certain class member variable. In Xcode4.5 and later versions, @synthesize can be omitted. \ Before, many netizens were a little confused about the use of the Property in the tutorial I translated. They didn't know when to release and when to self.xxx = nil; at the same time, for Objective-c memory management and cocos2d memory management rules Not clear

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Kubernetes basics: a detailed introduction to Pod

The exercise environment in this article is a Kubernetes cluster based on Virtualbox. For specific steps, please refer to kubeadm to install kubernetes V1.11.1 cluster. 1. Basic concepts 1.1 What is a Pod Pod is the smallest unit that can be created and deployed in Kubernetes. It is an application instance in a Kubernetes cluster and is always deployed on the same node Node. Pod contains one or more containers, as well as the resources shared by each container such as storage and network. Pod s

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GO Language Learning Special

1. GO environment installation 2. GO basic knowledge learning Language data type Boolean: bool Boolean values can only be constants true or false When formatting output, you can use %t to indicate that the value you want to output is Boolean. For Boolean values, good naming can improve the readability of the code, such as isFinished starting with is. var b bool = true Number type: The default value of number type is 0 The int type is the fastest calculation type Go is a strongly typed language a

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[Image recognition] Fingerprint recognition based on template matching

Fingerprint recognition technology is mainly divided into three steps: fingerprint preprocessing, feature extraction, fingerprint classification and matching. Whether it is fingerprint classification or fingerprint matching, it is necessary to extract effective features of fingerprints, and the performance of feature extraction largely depends on the quality of fingerprint images. In practical applications, due to the factors of acquisition conditions and acquisition equipment, the quality of th

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