• Common methods and properties of arrays in JS


    This paper summarizes the common methods and attributes of arrays in JS Three ways to create an array 1. Conventional method var arr = new Array (); arr[0]=”abc”; arr[1]=”def” 2. Simple way var arr = new Array(“abc”,”def”); 3. Literal measure var arr = []; arr=[“abc”,”def”]; perhaps var arr=[“abc”,”def”] Properties of an array object attribute describe […]

  • Implementation of JavaScript a simple promise


    Original address of this blog Most of us use it in the development processpromiseYou must be rightpromiseToday we are going to implement a simplepromiseIf there is any difference in the effect, correct it. Overall structure Let’s sort out the overall results first, so as to facilitate the subsequent operation class MyPromise { constructor(fn){ } resolve(){ […]

  • Process monitoring of Linux shell practice


    Requirements: monitor the system for nginx. Every 3 seconds, the successful output test succeeds, the failed output test fails and restart the nginx serviceThe code is as follows (for reference only, the case is applicable to the author’s own MBP) #!/bin/bash Echo “this is the first case of shell programming.” #Start of monitoring while true […]

  • A brief introduction of C + + 11 regex regular expression


    The main types involved in the regex library are: The processing string type represented by STD:: string (we know that there are wstring classes storing wchar_t, native c-string const char * and so on. In order to simplify the processing, only the operations related to the type of STD:: string are introduced. When you grasp […]

  • View MySQL execution plan


    1. MySQL syntax MySQL provides the explain syntax for query analysis. Add an “explain” before the SQL statement. By default, MySQL profiling is turned off, so you must first turn on profiling set profiling=”ON” mysql> show variables like “%profi%”; +————————+——-+ | Variable_name | Value | +————————+——-+ | profiling | ON | Show processlist; view the […]

  • Thorough understanding of browser caching mechanism


    Highlight: the article is clear and penetrating. Summary The caching mechanism of browser is what we callHTTPThe caching mechanism is based onHTTPThe message is cached. So before we analyze the browser cache, let’s use graphics and text for a brief introductionHTTPMessage,HTTPThere are two types of messages: HTTPRequest (RequestMessage. The message format is: Request line。 HTTPhead(general […]

  • Tensorflow operation mode


    [toc] The tensorflow construction diagram mainly consists of three pattern functions:inference(), loss(), train() inference() Build the graph and return the sensor containing the prediction results loss() inference()Add a loop on the built diagram toinference()The return of is one of the inputs, and finally the sensor containing the loss value is returned training() training()Minimization by gradient […]

  • MySQL MHA /usr/share/perl5/vendor_perl/MHA/ServerManager.pm, ln301] install_driver(mysql) failed: Attempt to reload DBD/mysql.pm aborted


    In the company, I found three testing machines to build an MHA. The following problem has been tossed for three days. I haven’t met it before. I checked the OS version and found that it was the same. Maybe it was the OS made by different people. I know that the problem of cpan is […]

  • MS17 in MSF


    1. Auxiliary / scanner / SMB / SMB ﹐ MS17 ﹐ 010 / / scan detection vulnerability auxiliary module Scanning results show that the vulnerability exists in 2, 3 and 4 hosts! 2. Auxiliary / admin / SMB / MS17? Command / / scan the 445 online host MS17? 010 to exploit the 445 SMB […]

  • Record the daily JQ generation list developed with native JS once


    Recognition starts from the front end of Vue,When it comes to the original and JQ, I really feel that it’s hard to move. Record two experiences of doing small dome this time.1. JQ dynamically generates HTML code. Without using the JQ template, you can directly manipulate the code fragment of DOM native generation loop. First, […]

  • Xgboost data competition actual combat adjustment (complete process)


    The content of this blog is based on the feature selection in the previous blog scikit, xgboost regression prediction, and the actual battle of model optimization. So before reading this blog, please move to the previous article. What I have done before is basically about feature selection. Here I want to write some experience about […]

  • MySQL Introduction (2) – database information reference


    We talked about MySQL and SQL structured query statements in the previous article, and we will learn about them step by step. 1. Login MySQLMySQL – u user name – P passwordFor example: mysql-uroot-pabc123The results are as follows: 2. Check the databaseshow databases;The results are as follows: 3. Use the specified databaseUse specified databaseFor example: […]