Caesar Cipher Before Refactoring

gistfile1.txt

$lower_case   = "abcdefghijklmnopqrstuvwxyz"
$upper_case = $lower_case.upcase

def caesar_encode(string, offset)
	array = string.split("")
	array.map! do |l| 
		if /[a-z]/ ===  l
			idx = $lower_case.rindex(l) 
			idx = (idx + offset) % 26
			$lower_case[idx]
		elsif /[A-Z]/ === l 
			idx = $upper_case.rindex(l)		
			idx = (idx + offset) % 26
			$upper_case[idx]
		else
			l
		end
	end
	array.join
end

def caesar_decode(string, offset)
	array = string.split("")
	array.map! do |l| 
		if /[a-z]/ ===  l
			idx = $lower_case.rindex(l) 
			idx = (idx - offset) % 26
			$lower_case[idx]
		elsif /[A-Z]/ === l 
			idx = $upper_case.rindex(l)		
			idx = (idx - offset) % 26
			$upper_case[idx]
		else
			l
		end
	end
	array.join
end