Tag:Li Si

  • The solution of writing CSV in Python and opening garbled code with Excel

    Time:2022-7-12

    The solution of writing CSV in Python and opening garbled code with Excel come from: https://blog.csdn.net/gwruiki/article/details/123645329 , thank the author.   It is mainly because the coding format is incorrect and cannot be usedencoding=’utf-8′, change toencoding=’GB18030’that will doAn example is shown below. with open(‘1.csv’, ‘w’, newline=”, encoding=’GB18030′) as cf: w = csv. Writer (CF) w.writerow […]

  • Figure database and cypher statement

    Time:2022-5-23

    Figure database and cypher statement 1. Understanding of graph database Recently, I accidentally used graph database in my work, and my understanding of the concept of graph database is still vague. At the beginning, the nodes and edges I understood can be understood as classes in Java in disguise. The label is the name of […]

  • Vue3 family bucket upgrade Guide – composition API

    Time:2022-5-22

    1、setup() The most important composition API in vue3 is the setup method, which is equivalent to the entry of components. All composition APIs must be used in setup (). Setup is executed before the component instance is initialized (before beforecreated). It is the entry function of the whole component. At this time, the data and […]

  • It’s easy to share screens through webrtc

    Time:2022-5-3

    brief introduction Use of screen sharing function commonly used in network conferenceProvided by webrtcgetDisplayMediaAPI can be easily implemented with the following interfaces var promise = navigator.mediaDevices.getDisplayMedia(constraints); Of mediadevices interfacegetDisplayMediaMethod prompts the user to select and grant permission to capture the contents of the display screen or parts thereof, such as browser windows and tabs, as […]

  • Redis – shopping cart

    Time:2022-4-10

    Refer to redis actual combat demand 1. Record the last access time of the user and count the latest access records of the user2. Record the products that the user has browsed recently, and the quantity of products is 53. Record the number of times the product is accessed, and only 5 popular data are […]

  • Redis – commodity trading

    Time:2022-3-19

    Refer to redis actual combat demand 1. The subject of commodity trading is an individual, who has name and asset attributes.2. Everyone has n items, and each item has a unique item number.3. Commodities are allowed to be put on the market for trading. Once they are put on the market, the commodities will be […]

  • Java – springboot add custom interceptor

    Time:2022-3-17

    Late one night, Nicholas Li Si had a whim: print the request log for the 10 interfaces he wrote during the day. The log content is also very simple. Just print the interface address and request parametersBut the code for printing the request log doesn’t want to be written in all 10 interfaces. What should […]

  • Basic usage of Android litepal 3.0 database

    Time:2022-3-11

    brief introduction Introduction to the usage of Guo Lin Litepal is an open-source Android database framework. It adopts the object relational mapping (ORM) mode and encapsulates some database functions most commonly used in our usual development, so that we can complete various operations of creating tables, adding, deleting, modifying and querying without writing one line […]

  • Introduction to markdown grammar

    Time:2022-3-7

    Markdown is a lightweight markup language title #Primary title ##Secondary title ###Tertiary title ####Four level title #####Five level title ######Six level title Primary title Secondary title Tertiary title Four level title Five level title Six level title typeface **Bold** *Italics* ***Bold and italic*** ~~Delete line~~~ BoldItalicsBold and italicDelete line~ Separation line — *** picture ! […]

  • Use pymysql to cycle through the duplicate data and modify the offset value of the auto increment field

    Time:2022-2-24

    Create table:   CREATE TABLE `info` (   `id` tinyint NOT NULL AUTO_INCREMENT,   `name` varchar(20) NOT NULL,   PRIMARY KEY (`id`)  ) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8  Insert data: insert into info (` name `) value (‘zhang San ‘), (‘li Si’), (‘ma Po ‘), (‘wang Wu’); Insert again: insert into info (‘name ‘) value (‘zhang San’), (‘li Si ‘), (‘ma […]

  • [study notes] notes on the use of ES6 class

    Time:2022-1-28

    Class class The traditional method of JavaScript language is to define and generate new objects through constructors. Function even if the object is a function, there is no concept of class. ES6 provides writing methods closer to traditional languages, such as Java, PHP and other back-end languages, and introduces the concept of class as the […]

  • Isolation level of transactions and transactions in MySQL

    Time:2022-1-28

    This article is mainly to help understand relevant knowledge, without specific operation and code. affair A transaction is a set of operations that either succeed or fail. The most classic example is bank transfer: Zhang San transfers 100 to Li Si, which is an operation for users. But corresponding to the database, at least three […]