>[success] # js 正则 ~~~ 1.正则表达式，又称规则表达式。（英语：Regular Expression，在代码中常简写为regex、regexp或RE）， 正则表达式通常被用来检索、替换那些符合某个模式(规则)的文本。 2.用来匹配字符串 3.正则表达式的组成:是由元字符或者是限定符组成的一个式子 ~~~ >[danger] ##### 元字符   >[danger] ##### 字符集合  >[danger] ##### 量词  >[danger] ##### 分支  >[danger] ##### 贪婪与懒惰 ~~~ 1.'贪婪模式'——在匹配成功的前提下，尽可能多的去匹配 2.'惰性模式'——在匹配成功的前提下，尽可能少的去匹配 说明:js 正则默认是贪婪模式,就是符合情况下尽可能多的去匹配 ~~~ ~~~ const str = 'I want you to (match the content) between the bracket)'; // 贪婪匹配只要满足我都要 console.log(/((.*))/.exec(str)); // 惰性遇到? 问号的意思是满足零次或者一次 也就是最少次数 // + 加号的意思是一次或者多次也就是 配合问号最少次数 则满足一次即可 console.log(/((.+?))/.exec(str)); // 找到满足非( 开始的字符以贪婪匹配则满足的都要 console.log(/(([^(]*))/.exec(str)); // 找到满足非( 开始的字符以惰性匹配则满足即第一个满足 console.log(/(([^(]+?))/.exec(str)); ~~~ * 输出打印结果 ~~~ [ 'I want you to (match the content) between the bracket)', 'I want you to (match the content) between the bracket)', 'I want you to (match the content) between the bracket)', index: 0, input: 'I want you to (match the content) between the bracket)', groups: undefined ] [ 'I', 'I', 'I', index: 0, input: 'I want you to (match the content) between the bracket)', groups: undefined ] [ 'I want you to ', 'I want you to ', 'I want you to ', index: 0, input: 'I want you to (match the content) between the bracket)', groups: undefined ] [ 'I', 'I', 'I', index: 0, input: 'I want you to (match the content) between the bracket)', groups: undefined ] ~~~