class Prime
Public Instance Methods
factors(n,primes)
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# File lib/prime.rb, line 2 def factors(n,primes) is_prime = true n_sqrt = Math.sqrt(n).ceil selected_primes = primes.select {|num| num<=n_sqrt } selected_primes.each {|x| (is_prime=false; break) if n%x==0 } is_prime end
get_nth_prime(n)
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# File lib/prime.rb, line 11 def get_nth_prime(n) prime_ary = [] first_digit = 1 next_digit = first_digit + 1 while (prime_ary.length < n) do (prime_ary << next_digit) if factors(next_digit,prime_ary) next_digit.even? ? next_digit += 1 : next_digit += 2 end p "Your #{n}th Prime Number is : #{prime_ary.last}" prime_ary.last end