Tag:Key value

  • ES6 set and map data structure

    Time:2020-11-26

    Set is a new data structure of ES6, which is characterized by the absence of members with the same value Set Set itself is a constructor used to generate the set data structure const set = new Set(); [1,2,2,3,4,5,6,7,5,8,9].forEach((x)=>{    set.add(x);}) console.log(set);  // [1,2,3,4,5,6,7,8,9] The set constructor takes an array or class array as a […]

  • Part / Multipost requests are constructed using HTTP

    Time:2020-11-19

    1、 Multipart / form data The difference between multipart / form data post and ordinary post request is reflected in two parts: request header and request body. Request header The content type information must be included, and its value must be specified as multipart / form data. At the same time, a content separator should […]

  • JS Basics

    Time:2020-11-15

    test1-helloworld Create a new test1.html file with the following contents, and then open it with a browser <!DOCTYPE html> <html lang=”en”> <head> <meta charset=”UTF-8″> <title>test1</title> </head> <body> <h1>My first JavaScript program</h1> <script> //Call the alert method, and the browser will pop up a prompt box alert(“Hello JavaScript”); </script> </body> </html> Where should JS be written? […]

  • Go comprehensive analysis of JSON tag

    Time:2020-11-14

    When processing the JSON format string, we often see that when declaring the struct structure, there are back quotation marks around the right side of the attribute. The shape is as follows: 1 type User struct { 2 UserId int `json:”user_id” bson:”user_id”` 3 UserName string `json:”user_name” bson:”user_name”` 4 } Struct member variable tag description To […]

  • (2) Analysis of Hadoop’s MapReduce principle

    Time:2020-11-7

    brief introduction MapReduce is aProgramming framework of distributed computing programIt is the core framework for users to develop “Hadoop based data analysis application”. The core function of MapReduce is to integrate the business logic code written by users and its own default components into a complete distributed computing program, which runs concurrently on a Hadoop […]

  • Building blockchain based on Java language (3) — persistence & command line

    Time:2020-11-7

    The final content is subject to the original texthttps://wangwei.one/posts/35c… introduction LastIn this paper, we implement the proof of work mechanism (POW) of blockchain to realize mining as much as possible. However, there are still many important features that have not been implemented from the real blockchain application. Today, we will implement the storage mechanism of […]

  • (3) Easy to understand how MapReduce works

    Time:2020-11-6

    I wrote an article earlier\(2) analysis of Hadoop’s MapReduce principleLater, it seems that I read it several times. Even I think it is too boring. Even the author himself has a hard time reading it, which shows that the writing is not good. =Therefore, we decided to simplify the work of MapReduce on the basis […]

  • MySQL B + tree index

    Time:2020-11-4

    1、 Overview of B + tree index Indexing is an important aspect of application design and development. If there are too many indexes, the performance of the application may be affected (the structure and data of the index need to be maintained); if there are too few indexes, the query performance will be affected. In […]

  • Record some problems of normal development (2)

    Time:2020-11-3

    1. In order to improve the user experience, click the text next to the radio box circle to select the click box The first way: <label for=”radiobutton”> < input type = “radio” name = “RadioButton” id = RadioButton “value =” RadioButton “/ > test? </label> The second way: <div> <input type=”radio” id=”modeltype5″ name=”” v-model=”” value=”” […]

  • Learning notes of set and map

    Time:2020-10-30

    Personal understanding: set is similar to one-dimensional array, and map is similar to two-dimensional array or object Similarities The feeling is that there are several basic attributes and methods with the same name and function: The size attribute returns the number of elements Clear clears all elements Delete removes the specified element Foreach traverses data […]

  • Set and map notes

    Time:2020-10-29

    Personal understanding: set is similar to one-dimensional array, and map is similar to two-dimensional array or object Similarities The feeling is that there are several basic attributes and methods with the same name and function: The size attribute returns the number of elements Clear clears all elements Delete removes the specified element Foreach traverses data […]

  • A brief analysis of the principle of scan code landing

    Time:2020-10-27

    I have always used wechat reading habits, and recently found that wechat reading also has a web version. To log in to the webpage version of wechat reading, we need to use app code scanning to log in. As shown in the following interface: Use your wechat to read the app, scan the QR code […]