programming is hard

Random Elements

class Array
  # returns a random element of the array
  def rand
    self[Kernel.rand(length)]
  end
end

class Hash
  # returns a random key-value pair
  def rand
    temp_key = self.keys.rand
    [temp_key, self[temp_key]]
  end
end

module Kernel
  # random_n_digit_number(1) returns a number between 1 and 9 inclusive
  # random_n_digit_number(3) returns a number between 100 and 999 inclusive
  def random_n_digit_number(n)
    raise ArgumentError, "expected digit length to be greater or equal to 1, received #{n.inspect}" if !n.is_a?(Numeric) || n < 1
    return rand(10) if n == 1
    min = 10**(n-1)
    max = (10**n)-1
    rand(max-min+1) + min
  end
end

class Range
  # (1..10).rand returns a number between 1 and 10 inclusive
  # (1...10).rand returns a number between 1 and 9 inclusive
  # (2..2).rand returns 2
  # (2...2).rand is equivalent to 2 + Kernel.rand()
  # (Date.parse('2008-08-01')..Date.parse('2008-08-31')).rand returns a date between the first and last dates 
inclusive
  # (Time.now..(Time.now+60)).rand returns a time between the first and last times inclusive
  def rand
    self.first + Kernel.rand(self.last - self.first + (self.exclude_end? ? 0 : 1))
  end
end