• [regular expression series] quick start


    introduction First of all, please let go of the fear and disgust in your heart! What regular has to say Is regular expression difficult? It’s not easy to master it. It needs a lot of practiceBut if you are just a beginner, you can write some simple expressions (such as mailbox verification, etc.), which is […]

  • Mysql database: operators


    operator Comparison operator: >Greater than < less than >=Greater than or equal to < = less than or equal to =Equal to ! = not equal to Range operator: Between… And… Is similar to > = and<=Not between… And Set operators In is similar to = or=Not in (value is not in this set) External […]

  • [regular expression series] basic usage


    preface stayquick get startIn this paper, the examples are all throughtest()Method demonstration, this article will continue to introduce other uses of regularJSLanguage) outline Regular object Generate regular objects Optional tag Subexpression Regulartestmethod Regularcompilemethod Regularexecmethod Regular application of string Stringmatchmethod Stringreplacemethod Stringsearchmethod Stringsplitmethod Regular object Generate regular objects There are two ways to create and get […]

  • 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 […]

  • Oracle foundation – query statement (2)


    Where clause Immediately after the from sentence. Syntax: SELECT *|{[DISTINCT] column|expression [alias], …} FROM table [WHERE condition(s)]; Tips: Strings and dates can be used in expressions in the select clause and in expressions in the where condition. String and date should be marked in single quotation marks. String case sensitive The date has a certain […]

  • [regular expression series] zero width assertion


    preface In regular expressions, there is a barrier that cannot be bypassed, that isZero width assertion Zero width assertionIt is a zero width match, and its matching content will not be saved in the matching results, and will not occupyindexWidth, the final match results in only one position In short, it is used to find […]

  • JS uses regular subexpressions to match words with the same initial and end letters


    In this paper, the example describes JS using regular subexpressions to match the first letter and the last letter of the same word. Share with you for your reference. The specific implementation method is as follows: Copy codeThe code is as follows: <html> <head> <script type=”text/javascript”>//Subexpression instance: find word with same initial and ending function […]

  • Case analysis of positive and negative prefetch in regular expressions


    In this paper, the positive and negative pre queries in regular expressions are illustrated. Share with you for your reference. The specific analysis is as follows: Here’s an example to explain what a forward lookup is. Example: there is a paragraph called “coming soon, going go gogogo”, which requires finding out com and go. The […]

  • Case analysis of single line pattern and multi line pattern in JS regular expression


    This paper analyzes the single line pattern and multi line pattern in JS regular expression. Share with you for your reference. The details are as follows: JS regular expressions do not support single line mode. That is to say, you can’t treat a certain content (with line breaks) as a pattern modifier, so that the […]

  • [regular expression series] some concepts (character group, capture group, non capture group)


    preface This paper introduces some common nouns and corresponding concepts in regular, such as character group, capture group, non capture group, reverse reference, escape and\s \betc. outline Character group Capture group Reverse reference Non capture group .、\sand\S \b \Escape Character group []Character group represents various characters that may appear in the same position, that is […]

  • Promise: from two blind eyes to two bright eyes (9) – Async and await


    Async function MDN document of Async 1. The return value of async function is promise object 2. The result of promise returned by async function is determined by the result of function execution async function fn1() { return 1 } The output of console.log (fn1()) is of promise type async function fn1() { Return 1 […]

  • Spring series 8: @ value details 2


    1. Premise Test properties file: advance_value_object.properties server.name=server1,server2,server3 #spelDefault.value\=notdefault HelloWorld\_\=sss Test class advance value inject: introduce the advance_value_inject.properties file as the property injection @Component @PropertySource({“classpath:com/hry/spring/configinject/advance\_value\_inject.properties”}) public class AdvanceValueInject { … } 2. Chen {…} and ${…} ${…}Usage The content in {} must conform to the spel expression and detailed syntax. You can open a new article […]