• Oracle foundation – query statement (1)


    Oracle foundation – query statement (1) Syntax of query statement SELECT \* |{\[DISTINCT\] column|expression \[alias\], … } ​ FROM table ​ WHERE conditions ​ GROUP BY ​ ORDER BY column \[ASC | DESC\]; Tips: Case insensitive Can be written in multiple lines Keywords cannot be abbreviated or across multiple lines Usually each clause takes one […]

  • Deep understanding of ES6 modules


    Learn more about ES6 modules At present, almost all of our projects are developed based on Web pack, roll up and other construction tools, and modularity is the norm. We are not new to it. Today, we will review the module mechanism of ES6 systematically, and summarize the commonly used operations and best practices, hoping […]

  • Object oriented explanation


    preface Before the formal start of the text, I want you to think about a few questions: 1. What is object-oriented? 2. What are the characteristics of object-oriented? 3. What are the inheritance methods of object-oriented? OK, after reading these three questions, let’s start with the content of the text. text 1、 Object oriented JS […]

  • 200 IOS interview questions. There are all the questions needed by the bottom and technology companies


    A collection of interview questions from 100 well-known enterprises in IOS this year: You want everything here; There are also what enterprises want here; From the beginning of the foundation to the advanced level and to the bottom Sort out 188 interview questions. They’re all dry goods Catalog display: 1. The difference between swift and […]

  • [swift] obtain the text of a function label clicked in uilabel and make response action


    1. Demand   First of all, make color mark prompt for multiple function labels displayed in uilabel. Secondly, click on the keyword to respond. As shown in the figure: solve: 1. Use regular matching to keywords public static var hashtag = DetectorType.custom(try! NSRegularExpression(pattern: “#[\\u4e00-\\u9fa5a-zA-Z0-9]{1,}”, options: [])) Extension: get the string satisfying the regular expression in the […]

  • How to solve the problem that sublime text 3 cannot display Chinese correctly


    When I used sublime text 3 on windows today, I found that after some TXT texts were opened, the Chinese characters were all garbled. So I searched and found a solution. Step: In sublime text, press Ctrl + ‘to open console, and input the following code at one time: import urllib.request,os; pf = ‘Package Control.sublime-package’; […]

  • Java Basics


    1: Identifier, keyword, data type, variable, constant. 2: Operators and expressions 3: Selection cycle structure of process control 4: Array        identifier : used to define constants, variables, methods, classes, interfaces, which are composed of letters, numbers, underscores and dollar characters.        keyword: for example, abstract, class, final, etc The data […]

  • Openresty + Lua entrance


    These days, I began to contact openresty + Lua. When looking at the code and materials, I kept thinking about where the code entry is. Since C, the first sample program of each language is almost “Hello, world”, just like a signboard: “enter from here”. The entry of openresty + Lua is in the configuration […]

  • Go logical judgment (if, else if, else, switch)


    1、 If logic judgment package main import “fmt” func main() { var a =10; If a > 10 {// carriage return is not allowed before brace fmt.Println(“dayu10”) }else if a<10{ fmt.Println(“xiaoyu10”); }else { fmt.Println(“10”) } } //There’s nothing better than a lot of introductions. That’s all 2、 Switch Mode 1 Switch to variable package main […]

  • C programming (22): insertion sorting


    Example 22 insert sort Problem description Sorting is an important operation in computer programming. Its function is to rearrange an arbitrary sequence of data elements or records into an ordered sequence of increasing (or decreasing) key words. There are many ways to sort. Simple insertion sort is a simple sort algorithm. The basic idea of […]

  • SQL Query Optimization Practice


    Why optimize The throughput bottleneck of the system often appears in the access speed of the database, that is, with the running of the application program, the data in the database will be more and more, the processing time will be slower correspondingly, and the data is stored on the disk, so the read-write speed […]

  • Analysis of the difference between two mechanisms of Java exception handling


    This article mainly introduces two mechanisms of Java exception handling keyword differential analysis. The example code is introduced in detail in this article, which has a certain reference learning value for your study or work. You can refer to the following for friends who need it What is the difference between throws and throws in […]