Regular expression of ES5 Foundation 01: First Meeting

1. Regular first meeting

Test Address: https://regexper.com

First regular: Match 2006-10-11 or 2006/10/11

var reg =/^\d{4}[-/]\d{2}[-/]\d{2}$/;

The above notation means that a regular object is created using literals

There is, of course, a way to create a regular expression by using the RegExp () constructor.

    //Online test tool: https://regexper.com/    //First regular match: 2006-10-11 or 2006/10/11    varReg =/^\d{4}[-/]\d{2}[-/]\d{2}$/; /*RegExp Object * JavaScript supports regular expressions through built-in object RegExp * There are two ways to instantiate a RegExp object * 1. Literal * 2. Constructors*/    /*1. Replace the string: Replace the word is with is * here by default matches the first one*/    varString = ' This is a girl '; String= String.Replace (/\bis\b/, ' is '));    Console.log (string); //\b (Word) \b is a word that matches a complete word;    //so how to achieve the full text? Use modifier g    varString = ' This is a girl '; String= String.Replace (/\bis\b/g, ' is '));    Console.log (string); /*2. Using the constructor * var reg = new RegExp (string,) * Constructor REGEXP () accepts two parameters, the first is regular, the second is a modifier*/    varReg =NewREGEXP (' \\bis\\b ', ' g '); /*3. Modifier * G:global, indicates full-text search, if not added then search to first stop * i:ignore, ignore case, default case sensitive * M:multipul lines multi-line match*/    //Test modifier i    varString = ' This is a girl '; String= String.Replace (/\bis\b/g, 0);    Console.log (string); //the above will only replace the first is with a 0    //Test modifier i    varString = ' This is a girl '; String= String.Replace (/\bis\b/gi, 0);    Console.log (string); //The above will replace two is with 0, because I makes the matching pattern insensitive to case

Regular expression of ES5 Foundation 01: First Meeting