Created
October 29, 2019 13:16
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ISIN code validator in Ruby
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class IsinCodeValidator | |
ISIN_FORMAT = '^[A-Z]{2}[A-Z0-9]{9}[0-9]$'.freeze | |
ISIN_REGEX = Regexp.new(ISIN_FORMAT).freeze | |
LETTER_TO_CODE_VALUE = 55 # Ascii code for 'A' == 65 && 'A' == 10 in isin calculation cod | |
def self.valid?(str) | |
return false if str.nil? || !str.match?(ISIN_REGEX) | |
proc_isin = str.split(//) | |
key = proc_isin.pop.to_i | |
proc_isin = proc_isin.map do |e| | |
e.match?(/[A-Z]/) ? (e.ord - LETTER_TO_CODE_VALUE).to_s.split(//) : e | |
end.flatten!.reverse! | |
proc_isin.each_index do |i| | |
proc_isin[i] = (proc_isin[i].to_i * 2).to_s.split(//) if (i % 2).zero? | |
end.flatten! | |
((key + proc_isin.map(&:to_i).inject(:+)) % 10).zero? | |
end | |
end |
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