掌握JS正则表达式的关键元字符：解锁高效文本处理技巧

引言

JavaScript中的正则表达式是处理字符串的强大工具。它允许开发者进行复杂的模式匹配、搜索、替换和验证操作。正则表达式由一系列字符和元字符组成，其中元字符是正则表达式的灵魂，它们定义了匹配的规则和模式。掌握以下关键元字符，将帮助您解锁高效文本处理的技巧。

关键元字符详解

1. 字符匹配

• .：匹配除换行符以外的任意单个字符。

  
  let regex = /a./g;
  let str = "cat, bat, hat";
  let matches = str.match(regex);
  console.log(matches); // ["cat", "bat", "hat"]
  

• [ ]：匹配方括号内的任意一个字符（字符类）。

  
  let regex = /[abc]/g;
  let str = "bad cat, mad hat, rad rat";
  let matches = str.match(regex);
  console.log(matches); // ["a", "a", "a"]
  

• [^]：匹配不在方括号内的任意一个字符（否定字符类）。

  
  let regex = /[^abc]/g;
  let str = "bad cat, mad hat, rad rat";
  let matches = str.match(regex);
  console.log(matches); // ["d", "d", "d"]
  

2. 量词

• ?：匹配前面的子表达式零次或一次。

  
  let regex = /boon*/g;
  let str = "boon, boonful, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["boon", "boon"]
  

• +：匹配前面的子表达式一次或多次。

  
  let regex = /boon+/g;
  let str = "boon, boonful, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["boon", "boon"]
  

• *****：匹配前面的子表达式零次或多次。

  
  let regex = /boon*/g;
  let str = "boon, boonful, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["boon", "oon", "oon"]
  

• {n}：匹配确定的n次。

  
  let regex = /\d{2,3}/g;
  let str = "There are 12, 23, 1234, 12345 cats.";
  let matches = str.match(regex);
  console.log(matches); // ["12", "23", "1234"]
  

• {n,}：匹配至少n次。

  
  let regex = /\d{3,}/g;
  let str = "There are 12, 23, 1234, 12345 cats.";
  let matches = str.match(regex);
  console.log(matches); // ["1234", "12345"]
  

• {n,m}：匹配n到m次。

  
  let regex = /\d{2,4}/g;
  let str = "There are 12, 23, 1234, 12345 cats.";
  let matches = str.match(regex);
  console.log(matches); // ["12", "23", "1234", "12345"]
  

3. 定位符

• ^：匹配输入字符串的开始位置。

  
  let regex = /^boon/g;
  let str = "boon, boonful, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["boon"]
  

• $：匹配输入字符串的结束位置。

  
  let regex = /ful$/g;
  let str = "boonful, boon, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["ful"]
  

• \b：匹配单词边界。

  
  let regex = /\bboon\b/g;
  let str = "boonful, boon, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["boon"]
  

• \B：匹配非单词边界。

  
  let regex = /\Bboon\b/g;
  let str = "boonful, boon, boondoggle";
  let matches = str.match(regex);
  console.log(matches); // ["oon", "oon"]
  

4. 分组和引用

-