Class: Prime

Inherits:
Object
  • Object
show all
Defined in:
lib/hack01/nth_prime.rb

Class Method Summary collapse

Class Method Details

.is_prime(number_to_test) ⇒ Object 



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# File 'lib/hack01/nth_prime.rb', line 5

def is_prime number_to_test
  prime = true

  number_to_test
  arr = (2 .. (number_to_test - 1) ).to_a
  arr.each do |n|
    if (number_to_test % n) == 0
      prime = false
    end
  end

  return prime
end

.nth(num) ⇒ Object 



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# File 'lib/hack01/nth_prime.rb', line 19

def nth num

  throw ArgumentError.new unless num > 0

  primes = [2]
  candidate = primes.last

  while primes.length < num
    candidate = candidate + 1
    if is_prime candidate
      primes.push candidate
    end
  end
  # p primes
  primes.last
end