给定日期和星期几，找到将来最接近的日期

Question

假设星期几（假设周一），我需要找到最近的日期（将来）到给定日期（例如9-4-2016），这是一周中的这一天（对于这些例子，它应该是11-4- 2016）。

Answer 1

This is a pure Ruby solution.

require 'date'

d = Date.strptime('9-4-2016', '%d-%m-%Y')
  #=> #<Date: 2016-04-09 ((2457488j,0s,0n),+0s,2299161j)> 
d + (1 - d.wday) % 7
  #=> #<Date: 2016-04-11 ((2457490j,0s,0n),+0s,2299161j)> 

1 is Monday's offset. d.wday #=> 6 .

I have assumed that if the date falls on a Monday, the "closest" Monday is the same day. If it is to be the following Monday, use:

d + (d.wday == 1) ? 7 : (1 - d.wday) % 7

Answer 2

You can find this date in the nearest week of your date :

date =  Date.parse('9-4-2016')
(date..date + 6).find {|d| d.strftime("%A") == "Monday"}
#=> Mon, 11 Apr 2016