Rails如何为一个select标签创建一个数组？ [关闭]

Question

我的问题类似于Rails - return an array of months for a select tag。

但我想要一个这样的数组：

[
  ["September", 9], 
  ["August", 8],
  ["July", 7], 
  ["June", 6],
  ["May", 5], 
  ["April", 4],
  ["March", 3],
  ["February", 2],
  ["January", 1],
  ["December", 0]
  ["November", -1], 
  ["October", -2]
]

如果当前月份是 10 月，则为：

[
  ["October", 10]
  ["September", 9], 
  ["August", 8],
  ["July", 7], 
  ["June", 6],
  ["May", 5], 
  ["April", 4],
  ["March", 3],
  ["February", 2],
  ["January", 1],
  ["December", 0]
  ["November", -1]
]

Answer 1

应该这样做：

require 'date'
Date::MONTHNAMES[1..12].reverse.rotate(12-Time.now.month).each_with_index.collect{|m, i| [m, Time.now.month-i]}

编辑：

正如您在评论中提到的要显示年份，您需要一种不同的方法来“回到过去”。当你使用 rails 时，你可以使用 activerecord 的日期函数来做到这一点：

require 'active_support/core_ext/date/calculations'
t = Time.now
(0..11).collect { |i| current = t.advance(months:-i); ["#{Date::MONTHNAMES[current.month]} #{current.year}", t.month-i ] }