• Five minutes to fully understand the characteristics


    preface In work or study, it is inevitable to come into contact with features more or less. Maybe you don’t know what features are. Let me give you two examples [Objective], [httpget], [httppost], [serialized], [authorized filter]. Do you feel familiar? Let’s follow Xiao Zhao to find out. Attributes are used to add metadata, such as […]

  • Spark source code:: Spark multithreading:: nettyrpcenv.ask interpretation


    background There are many examples of asynchronous processing in spark, each of which is worth a good look. It will help us to understand the mechanism of spark and write elegant code for ourselves. Interpretation of nettyrpcenv.ask Effect of rpcenv NettyRpcEnvyesRpcEnvThe only implementation of in spark.RpcEnvWhat is it? You can look at its class header […]

  • 90s quickly know whether your app is safe and compliant!


    Now we almost always have mobile phones and all kinds of apps. What apps do you use most every day? Is it safe? Does it meet the green standard? Is it a green application? How to download or judge green application when installing software? Here, Xiaobian will contribute a few moves, take you into the […]

  • Pandas data analysis — detailed explanation of super easy to use groupby


    WeChat official account: “Python reads money”If there are any questions or suggestions, please official account message. In the daily data analysis, it is often necessary to analyze the dataDivide into different groups according to one (more) fieldFor example, in the field of e-commerce, the total sales of the whole country are divided by provinces, and […]

  • The power of immutable data


    The data immutability principle of state in react. Why is it so designed?Because in the life cycle of react, every call to componentshouldoupdate() will compare the existing data of state with the data to be changed, update the changed data, minimize unnecessary updates, and achieve performance optimization. Therefore, it is not recommended to change the […]

  • Handwritten react


    Small white with, welcome the big man to put forward the opinionActually write react in Vue community, ha ha ha preface White whoring class in Geek time, record the content and sublimate the knowledge hereCode warehouse address React code address As a beginner, I have a lot of things I don’t understand. I want to […]

  • Windows install Mongo, single machine open replication set


    Install Mongo: 1. To download Mongo, do not check the user-defined path and install mongodb compass (this is the graphical interface in the figure below, which can’t be moved at all). For other default configurations, you can use the next route.2. Configuration environment variable: D: program files mongodbserver4.4bin3. Create two directories, data and log, in […]

  • Summary of JavaScript regular expression


    This paper summarizes the content of JavaScript regular expressions. Table form, clear at a glance. With the help of example graphic explanation. 1、 Metacharacter 2、 Antonym character 3、 Escape character 4、 Repeated matching 5、 Group / capture 6、 Greed and inertia 7、 Modifier example Matches phone numbers that start with 11n, 12n or 1nnn, followed […]

  • Zero foundation to develop Hadoop learning route


    Week 2: November 2, 2020 to November 6, 20201. Basic concepts and characteristics of HDFS2. Deeply understand the architecture and underlying principles of HDFS in Hadoop ecosystem3. HDFS write process and read process4. Use of HDFS5. The relationship between HBase and HDFSWeek 1: 2020 / 10 / 27 – 2020 / 10 / 31 Let’s […]

  • Go daily news — February 19, 2020


    gocn_news_2020-02-19 1. Use t.cleanup to finish the test https://ieftimov.com/post/testing-in-go-clean-tests-using-t-cleanup/ 2. Go programming language specification https://moego.me/golang_ spec.html 3. Select case default https://mp.weixin.qq.com/s/zMZXd8DLtjhm06Q0lm1pcg 4. The design and implementation of Minerva in Betta configuration management center https://gocn.vip/topics/9794 5. How does go language work – linker https://mp.weixin.qq.com/s/_ 2y7oLfYftRxH8YTEm0qMw 6. Editor: yulibozi 7. Subscribe to news: http://tinyletter.com/gocn Go language Chinese […]

  • Go Technology Daily (February 28, 2020)


    Go language Chinese website (Daily News)_ 2020-02-28 1、 Go language Chinese network What about gopher’s low learning efficiency? Cao Da talks about how engineers should learn Default route matching rules in go HTTP packets Go playground / validator Starting from scratch k8s | kubernetes storage architecture and plug-in usage 2、 Graphic source code Illustration of […]

  • Go runtime debug tips


    From the official account: New World grocery store preface The original intention is to study the start-up process of Go program, and then go to the Internet to search for an introductory tutorial. It turned out to be a bit frustrating. Almost all the articles I found started with a passGDBDebugging, then assembly code on […]