hash  = {}
alpha = 'A'
for number in 1.upto(26)
	hash[alpha] = number
	alpha       = alpha.succ
end
 
MapOfAlphaToNumber = hash
 
 
def parse_excel_row_id(string)
	row_num = 0
	for alpha in string.split(//)
		raise 'Invalid Row ID' unless MapOfAlphaToNumber.has_key?(alpha)
 
		row_num = row_num * 26 + MapOfAlphaToNumber[alpha]
	end
 
	return row_num
end
 
 
printf "'A'   --> %d", parse_excel_row_id('A')
puts
printf "'AA'  --> %d", parse_excel_row_id('AA')
puts
printf "'ZZZ' --> %d", parse_excel_row_id('ZZZ')
puts
 

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