LeetCode 193. Valid Phone Numbers
分析
难度 易
来源
https://leetcode.com/problems/valid-phone-numbers/
题目
Given a text file file.txt
that contains list of phone numbers (one per line), write a one liner bash script to print all valid phone numbers.
You may assume that a valid phone number must appear in one of the following two formats: (xxx) xxx-xxxx or xxx-xxx-xxxx. (x means a digit)
You may also assume each line in the text file must not contain leading or trailing white spaces.
Example:
Assume that file.txt
has the following content:
987-123-4567
123 456 7890
(123) 456-7890
Your script should output the following valid phone numbers:
987-123-4567
(123) 456-7890
解答
https://leetcode.com/problems/valid-phone-numbers/discuss/55478/Grep-e-solution-with-detailed-explanation-good-for-those-new-to-regex
grep -e '\(^[0-9]\{3\}-[0-9]\{3\}-[0-9]\{4\}$\)' -e '\(^([0-9]\{3\})[ ]\{1\}[0-9]\{3\}-\([0-9]\{4\}\)$\)' file.txt
- In Bash, we use \ to escape next one trailing character;
- ^ is used to denote the beginning of a line
- $ is used to denote the end of a line
- {M} is used to denote to match exactly M times of the previous occurence/regex
- (...) is used to group pattern/regex together
Back to this problem: it requires us to match two patterns, for better readability, I used -e and separate the two patterns into two regexes, the first one matches this case: xxx-xxx-xxxx and the second one matches this case: (xxx) xxx-xxxx
加上-P
(使用Perl的正则引擎)即可过滤出目标数据
grep -P '^(\d{3}-|\(\d{3}\) )\d{3}-\d{4}$' file.txt
注意上方的空格
grep '^(\d{3}-|\(\d{3}\)[ ]{1})\d{3}-\d{4}$' file.txt
这里使用[ ]{1}表示一个空格
最新文章
- J2EE web项目中解决所有路径问题
- java接口的嵌套
- IT人学习方法论(一):学习方向
- Qt 按钮事件不响应
- TCP/IP协议 三次握手与四次挥手【转】
- bootstrap01登录小例子
- ACdream 1135(MST-最小生成树边上2个值,维护第一个最小的前提下让还有一个最小)
- java8之lambda表达式入门
- CS Round#53 C Histogram Partition
- JAVA数组练习
- css学习_css补充知识
- python学习(十一)
- FPGA-VHDL课堂学习笔记*01
- 动态编程(Dynamic Programming)
- 【转】Java finally语句到底是在return之前还是之后执行?
- 测试同学必备抓包工具--charles之mock数据
- 关于小程序登录时获取openId和unionId走过的坑
- Windows 计划任务 Task Schedule 怎么 运行 .bat文件
- 【Postgresql】set up
- Python使用Threading模块创建线程
热门文章
- 缓冲区溢出基础实践(一)——shellcode 与 ret2libc
- Golang包管理工具glide简介
- python获取网站http://www.weather.com.cn 城市 8-15天天气
- VC++中出现stack overflow错误时修改VC++的默认堆栈大小
- web常用的正则表达式
- 关于jquery的click()方法
- highcharts柱状图实现legend和数据列一一对应效果
- html中radio、checkbox选中状态研究
- 手把手教你写基于C++ Winsock的图片下载的网络爬虫
- iOS 基础函数解析 - Foundation Functions Reference