Question

My question is similar to Rails – return an array of months for a select tag.

But I want an array like this:

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

And if the current month were October, it would be:

[
  ["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

This should do it:

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

Edit:

As you mentioned in a comment you wanted to display the year, you need a different approach to “go back in time”. As you are using rails, you can use activerecord’s date functions to do that:

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 ] }