Description

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

Solutions

1. Grep

grep -P '^(\d{3}-|\(\d{3}\) )\d{3}-\d{4}$' file.txt
# no -P in MacOS
# 26/26 cases passed (4 ms)
# Your runtime beats 57.26 % of bash submissions
# Your memory usage beats 39.29 % of bash submissions (3.2 MB)

2. Sed

sed -n -r '/^([0-9]{3}-|\([0-9]{3}\) )[0-9]{3}-[0-9]{4}$/p' file.txt
# 26/26 cases passed (4 ms)
# Your runtime beats 57.26 % of bash submissions
# Your memory usage beats 96.43 % of bash submissions (3.1 MB)

3. Awk

awk '/^([0-9]{3}-|\([0-9]{3}\) )[0-9]{3}-[0-9]{4}$/' file.txt
# 26/26 cases passed (4 ms)
# Your runtime beats 57.26 % of bash submissions
# Your memory usage beats 14.29 % of bash submissions (3.3 MB)

References

  1. 193. Valid Phone Numbers
  2. 正则表达式中限定符与定位符的灵活使用