class MyNumber
Constants
- VERSION
Public Class Methods
corporate_number?(n)
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# File lib/mynumber.rb, line 4 def self.corporate_number?(n) return false unless n.to_s =~ /^\d{13}$/ digits = n.to_s.chars.map(&:to_i) check_digit = digits.pop sum = digits.map.with_index do |p, idx| # nが奇数のとき 1, nが偶数のとき 2 q = (idx + 1).odd? ? 1 : 2 p * q end.inject(0, :+) check_digit == (9 - sum % 9) end
individual_number?(n)
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# File lib/mynumber.rb, line 18 def self.individual_number?(n) return false unless n.to_s =~ /^\d{12}$/ digits = n.to_s.chars.map(&:to_i) check_digit = digits.pop remainder = digits.map.with_index do |p, idx| idx = 11 - idx # 1<=n<=6のとき n+1, 7<=n<=11のとき n-5 q = (idx <= 6) ? idx + 1 : idx - 5 p * q end.inject(0, :+) % 11 case remainder when 0, 1 check_digit == 0 else check_digit == (11 - remainder) end end