193. Valid Phone Numbers

題目敘述

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

題目翻譯

檔案 file.txt 中儲存了每一行的電話資料，需要寫一個 script 來驗證每一行的電話格式，並且輸出出來。其格式有兩種 (xxx) xxx-xxxx 和 xxx-xxx-xxxx。

解法解析

主要解法是使用了 Regex 來去做格式判別，分別針對 (xxx) xxx-xxxx 和 xxx-xxx-xxxx 編寫各自的 Regex。

解法範例

Bash

# Read from the file file.txt and output all valid phone numbers to stdout.
egrep -e '^\([0-9]{3}\) [0-9]{3}-[0-9]{4}$' -e '^[0-9]{3}-[0-9]{3}-[0-9]{4}$' file.txt