js正则获取某一段字符串，怎么写写！

Question

var str = 'http://www.8888123.xyz:2100/20181208/sy5E2uyc/index.m3u8';

//获取20181208/sy5E2uyc        
          
str = str.match(/表达式/);
                  
console.log(str)

项目中这个值的前后不变，唯独要获取着这个值会变化！！

Answer 1

var str = 'http://www.8888123.xyz:2100/20181208/sy5E2uyc/index.m3u8';                
str = str.match(/[^\/]+\/[^\/]+(?=\/[^\/]+$)/)[0];

Answer 2

let str = 'http://www.8888123.xyz:2100/20181208/sy5E2uyc/index.m3u8';
const reg = /^http:\/\/www.8888123.xyz:2100\/(\d{8}\/[a-zA-Z0-9]+)\/\index.m3u8$/;
str = str.replace(reg, '$1');
console.log(str)  // 20181208/sy5E2uyc

Answer 3

'http://www.8888123.xyz:2100/20181208/sy5E2uyc/index.m3u8'.match(/(?:.*\/)(.*\/.*\/).*/)[1];

Answer 4

var str = 'http://www.8888123.xyz:2100/20181208/sy5E2uyc/index.m3u8';
str = /http\:\/\/[^/]+\/([^/]+\/[^/]+)/.exec(str)[1];
console.log(str);

Answer 5

这种场景，吾辈更建议直接用截取而非正则（正则的可读性极差）＼（＠￣∇￣＠）／

Answer 6

单纯看着题写一下

var str = 'http://www.8888123.xyz:2100/20181208/sy5E2uyc/index.m3u8';

//获取20181208/sy5E2uyc        
          
str = str.match(/\d{8}\/\w*/)[0];
                  
console.log(str)