Цикл по массиву, используя проверку строки String # для поиска слов:
f = [
"happy days",
"happy\ndays",
"happy,days",
"happy, days"
]
require 'pp'
pp f.map{ |s| s.scan(/\w+/) }
>> [["happy", "days"], ["happy", "days"], ["happy", "days"], ["happy", "days"]]