• Usage Summary of Python collaborative process (I)


    1、 Python collaboration keyword Async: declare collaboration Note: the function declared through async is not a function, and a separate call will not be executed Await: it is used to wait for objects that can wait, including collaboration (that is, the collaboration declared by async), task (asyncio. Create_task(), asyncio ensure_ Future () is the task […]

  • iOS dispatch_ After delayed execution results in delayed dealloc


    Let’s build a new oneNewViewController, at the beginningViewControllerWrite the following code – (void)viewDidLoad { [super viewDidLoad]; UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom]; btn.frame = CGRectMake(100, 100, 100, 50); btn.backgroundColor = [UIColor brownColor]; [btn addTarget:self action:@selector(jump) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:btn]; } -(void)jump{ NewViewController *newVC = [[NewViewController alloc]init]; [self presentViewController:newVC animated:YES completion:nil]; } Then inNewViewControllerLi: -(void)dealloc{ NSLog(@”————–dealloc”); } – […]

  • Thoughts on go select deadlock


    Thoughts on go select deadlock https://mp.weixin.qq.com/s/Ov1FvLsLfSaY8GNzfjfMbg Continuous thinking triggered by an article Summary above Summary I package main import ( “fmt” ) func main() { ch := make(chan int) go func() { select { case ch No matter which case is finally selected by select, getval () will execute in the order of source code: […]

  • Fluent callback and multiple request dependency processing


    Only take important notes of flutter 1. Multiple request dependencies are only used to perform other operations after multiple asynchronous operations are completed. The key syntax is:Future.wait[], “wait“The array passed in asynchronous operation will be called only when all the results are returned.then()method Future.wait([ //Return results in 2 seconds Future.delayed(new Duration(seconds: 2), () { return […]

  • Introduction to Python + small routine


    PythonIs one of the most popular programming languages in the world PythonIt has occupied the first place in the ranking of various languages for many consecutive years. It has always been equal to R language in the field of data analysis, but in recent years, python has become more and more popularPythonAnalysis tool libraries have […]

  • Springboot integration spring data mongodb operation mongodb details


    quote:www.mydlq.club/article/85/ 1、 Introduction to mongodb Mongodb is a product between relational database and non relational database. It has the richest functions among non relational databases and is most similar to that of relational database. The data structure it supports is very loose. It is a JSON like bson format, so it can store more complex […]

  • [nanny level Python teaching] everything can be API


    Today, I saw an open source project called command2api. I feel very interesting and share it with you. origin The original repo has a paragraph about why this project was born: “ Take the recent rce of log4j as an example. In the intranet security test, due to the limitation of the network environment, there […]

  • Basic use of mysqli


    Simple example Process oriented approach //Create database connection $connect = mysqli_connect(‘’, ‘root’, ‘root’, ‘test’, 8889); //Judge whether the connection is successful if (!$connect) { Echo ‘database connection failed’; //Print reason for connection failure var_dump(mysqli_connect_error($connect)); exit(); } //Set character set mysqli_set_charset($connect, ‘utf8’); //Assemble SQL statements $sql = “SHOW TABLES”; //Execute SQL statement $res = mysqli_query($connect, $sql); […]

  • Crawler series: using API


    Application programming interface (API): it provides convenient and friendly interfaces for different applications. There is no problem for different developers to write software in different architectures or even different languages – because the purpose of API design is to become a communication language for different software to share information. Although different software applications have different […]

  • Use chrome to debug the typescript source code of vue3


    I believe many students have started vue3, which is really fragrant! How can you learn technology without learning the source code and look at the source code more? Maybe you’ll become a big man someday Today, I’ll record the process of debugging vue3 source code for future reference. preparation First, you need to download and […]

  • be careful! Monitor whether MySQL service is normal. Just understand these four methods


    Source: http://blog.chinaunix.net/uid-90618-id-5846539.html?utm_source=tuicool&utm_medium=referral Monitor whether the MySQL service is normal. The general idea is: check whether port 3306 is started, PS check whether the mysqld process is started, log in to MySQL from the command line, return the result of the execution statement, detect PHP or JSP programs (developers are required to develop programs), etc; Method […]

  • (4) MySQL advanced SQL optimization (optimization of common SQL)


    1. General Earlier, we introduced how to optimize queries through indexes in MySQL. In daily development, in addition to using query, we will also use some other common SQL, such as insert, group by, etc. How should we optimize these SQL statements? This section will introduce some optimization methods for these SQL statements. 2. Optimize […]