正则表达式学习

正则表达式是一个可以帮助我们匹配复杂字符串模式的工具

匹配字符(What)

• .
• [abcd] [a-zA-Z] [^abcd]
• \d \s \t \w ...

匹配数量(How)

• *
• +
• ?
• {n}
• {n,}
• {n,m}

子匹配

• ()

其他

• a* Greedy 贪婪
• a*? Lazy
• | 或
• ^ $

例子

93.180.71.3 - - [17/May/2015:08:05:32 +0000] "GET /downloads/product_1 HTTP/1.1" 304 0 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.21)"
93.180.71.3 - - [17/May/2015:08:05:23 +0000] "GET /downloads/product_1 HTTP/1.1" 304 0 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.21)"
80.91.33.133 - - [17/May/2015:08:05:24 +0000] "GET /downloads/product_1 HTTP/1.1" 304 0 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.17)"
217.168.17.5 - - [17/May/2015:08:05:34 +0000] "GET /downloads/product_1 HTTP/1.1" 200 490 "-" "Debian APT-HTTP/1.3 (0.8.10.3)"
217.168.17.5 - - [17/May/2015:08:05:09 +0000] "GET /downloads/product_2 HTTP/1.1" 200 490 "-" "Debian APT-HTTP/1.3 (0.8.10.3)"
93.180.71.3 - - [17/May/2015:08:05:57 +0000] "GET /downloads/product_1 HTTP/1.1" 304 0 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.21)"