Regex to match mm/dd/yyyy hh:mm:ss AM or PM

Question

I have a program that creates information for a time stamp, the time stamp has to match the following format: MM/DD/YYYY HH:MM:SS AM or PM

For example:

Answer 1

I don't think a regex is the right tool for this job. I'd use DateTime.strptime, give it the format you're expecting and let it deal with all the "50 hours is invalid in a time of day", "09 versus 9", ... issues.

Something like:

require 'date'

def timestamp
  print 'Enter the time stamp to verify: '
  ts = gets.chomp # You might want to include a String#strip call in here too
  DateTime.strptime(ts, '%m/%d/%Y %I:%M:%S %p')
  puts ts
rescue ArgumentError
  puts 'Invalid formatting of time stamp'
  exit 1
end

Regexes are nice but they shouldn't be the only parsing tool you have.