Ruby代码获取下周一(或一周中的任何一天)的日期

Question

给定一个输入，例如，

day = 'Monday'

如何计算下一个天的日期？

def date_of_next(day)
  ...
end

Answer 1

require 'date'

def date_of_next(day)
  date  = Date.parse(day)
  delta = date > Date.today ? 0 : 7
  date + delta
end

Date.today
#=>#<Date: 2011-10-28 (4911725/2,0,2299161)>
date_of_next "Monday"
#=>#<Date: 2011-10-31 (4911731/2,0,2299161)>
date_of_next "Sunday"
#=>#<Date: 2011-10-30 (4911729/2,0,2299161)>