• Machine learning from 0 – neural network recognition of handwritten characters!


    1、 Problem description Today, Denglong shared with you the method of using feedforward neural network to recognize 10 types of handwritten characters. Students who don’t know the basics of neural network can check my last article:Machine learning from 0 – Fundamentals of neural networks Our goal is to use a trained neural network to predict […]

  • [interview skills] n common skills of using CSS to realize triangles


    In some aspects, you can often see that there is a topic about CSSHow to draw triangles using CSS, and the usual answers are usually drawn using border. With the development of CSS today, there are many interesting ways to draw triangles only using CSS. This article will list them in detail. Through this article, […]

  • Network Protocol HTTP protocol (I)


    HTTP protocol  It’s a kind ofStateless、Application layer, toRequest / replyIt uses extensible semantics and self describing message format, and network-basedHypertext informationThe system interacts flexibly. 1. Schematic diagram of HTTP request scenario 2. Flow chart of HTTP request initiated by browser 3. Schematic diagram of DNS resolution process DNS resolutionThe purpose of domain name string is […]

  • Disembarkation algorithm leetcode weekly contest 259 problem solving Report


    [No.1 variable value after operation] Problem solving ideasCheck in question. Code display class Solution { public int finalValueAfterOperations(String[] operations) { int v = 0; for (String op : operations) { if (op.contains(“++”)) { v++; } else { v–; } } return v; }} [No.2 sum of array values] Problem solving ideasThe beauty value of the […]

  • Write OS kernel from scratch – display and print


    Series catalog Preface preparation BIOS boot to real mode GDT and protection mode On virtual memory Load and enter the kernel Display and print Global descriptor table GDT Interrupt processing Virtual memory perfection Implement heap and malloc First kernel thread Multithread switching Lock and multithreading synchronization Enter user status Process implementation system call Simple file […]

  • Linux notes 1


    Wildcard *? [] [^] Command line cursor home end Ctrl + U Ctrl + K Ctrl + arrow Ctrl + L echo $HISTFILE, $HISTFILESIZE, $HISTSIZE !100 !-5 !! !$ (esc + .) !string $(cmd) `cmd` mkdir -pv ./test/{x/m,y} ./test2/{a,d}_{b,c} The files copied by CP belong to the primary group and the user who is currently […]

  • Linux text processing


    <!– /\* Font Definitions \*/ @font-face {font-family:”Cambria Math”; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} @font-face {font family: isoline; panose-1:2 1 6 0 3 1 1; MSO font ALT: Dengxian; MSO font charset: 134; MSO generic font family: Auto; MSO font pitch: variable; […]

  • Sed command notes


    Sed loads the content line by line into the memory space, processes it, and then prints it to the screen; The default is not to modify the source file Sed – niefr ‘line action modifier’ file -N in silent mode, only the processed lines are printed -I modify the source file directly -e script -e […]

  • Learn a Linux command every day (42): unzip


    Yesterday’s recommendation:Learn a Linux command every day (41): zip Command introduction The unzip command is used to extract the compressed package file compressed by the zip command. #Debian / Ubuntu installation apt-get install unzip #CentOS installation [[email protected] ~]# unzip -bash: unzip: command not found [[email protected] ~]# yum install unzip -y Syntax format unzip [ OPTIONS ] file[.zip] [file(s) …] Option description -c   # Output the decompressed results and convert the characters appropriately -f   # […]

  • Interpretation of Vue source code IV: ast abstract syntax tree


    The content of this article istemplate engineOn the basis ofVirtual DOMBased on the relationship between the three, the following figure is summarized: graph TD A [template syntax] – > | parsing | B (abstract syntax tree AST) B — > | call | C [rendering function is h function] C — > | generate | […]

  • How does golang flip any string containing Chinese numbers, English letters and so on


    Problem description Flip containsChinese, numbers, English lettersAny string such as Example Input: “he Shi l FA lo, world. + – * boundary, 6” Output: “6, boundary * – +. World, ol hair l division eh” Golang implementation package main import “fmt” func reverseString(s string) string { //Converts a string to a slice of type Rune […]

  • Using UTF-8 in MySQL


    So what is coding? What is UTF-8? A brief history of MySQL Why is it so crazy summary Recently, I encountered a bug. I tried to save a UTF-8 string in “utf8” encoded MariaDB through rails, and then a strange error occurred: Incorrect string value: ‘\xF0\x9F\x98\x83 I use the UTF-8 encoded client, the server is […]