“Ruby, jeśli daty jest w zasięgu” Kod odpowiedzi

Ruby, jeśli daty jest w zasięgu

d1      = DateTime.parse('2018/04/01')
  d2      = DateTime.parse('2018/04/29')
  outside = DateTime.parse('2018/04/30')
  inside  = DateTime.parse('2018/04/15')

  # include?
  (d1...d2).include?(d1)      # true
  (d1...d2).include?(d2)      # false
  (d1...d2).include?(outside) # false
  (d1...d2).include?(inside)  # true

  (d1..d2).include?(d1)      # true
  (d1..d2).include?(d2)      # true
  (d1..d2).include?(outside) # false
  (d1..d2).include?(inside)  # true

  # ===
  (d1...d2) === d1      # true
  (d1...d2) === d2      # false
  (d1...d2) === outside # false
  (d1...d2) === inside  # true

  (d1..d2) === d1      # true
  (d1..d2) === d2      # true
  (d1..d2) === outside # false
  (d1..d2) === inside  # true

  # cover?
  (d1...d2).cover?(d1)      # true
  (d1...d2).cover?(d2)      # false
  (d1...d2).cover?(outside) # false
  (d1...d2).cover?(inside)  # true

  (d1..d2).cover?(d1)      # true
  (d1..d2).cover?(d2)      # true
  (d1..d2).cover?(outside) # false
  (d1..d2).cover?(inside)  # true

  # between?
  d1.between?(d1, d2)       # true
  d2.between?(d1, d2)       # true
  outside.between?(d1, d2)  # false
  inside.between?(d1, d2)   # true