在两个日期之间获得独特的月份和年份数组。-Getuniquearrayofmonthandyearsbetweentwodates

4  

require 'date'

def doit(first, last)
  (12*last.year + last.month - 12*first.year - first.month).times.map do
    first.strftime("%b %Y")
    first = first >> 1
  end
end

first = Date.parse('Fri, 02 Dec 2016')
last  = Date.parse('Wed, 01 Mar 2017')
doit(first, last)
  #=> ["Dec 2016", "Jan 2017", "Feb 2017", "Mar 2017"]

3  

You could create an array of dates, then use strftime to set the correct format, and uniq to avoid repeated values, like this:

您可以创建一个日期数组，然后使用strftime来设置正确的格式，并使用uniq来避免重复的值，比如:

(first..last).map{ |date| date.strftime("%b %Y") }.uniq
#=> ["Dec 2016", "Jan 2017", "Feb 2017", "Mar 2017"]

3  

Since user asks for most efficient way (and just for fun) here's a simple benchmark of the proposed solutions:

由于用户要求使用最有效的方法(而且仅仅是为了好玩)，这里有一个简单的基准来衡量所提出的解决方案:

require 'benchmark'

Benchmark.bmbm(10) do |bm|
  bm.report('Cary') do
    first = Date.new(1000, 1, 1)
    last  = Date.new(2100, 1, 1)

    def doit(first, last)
      (12*last.year + last.month - 12*first.year - first.month).times.map do
        first.strftime("%b %Y")
        first = first >> 1
      end
    end

    doit(first, last)
  end

  bm.report('Simple Lime') do
    first = Date.new(1000, 1, 1)
    last  = Date.new(2100, 1, 1)

    dates = []

    while first.beginning_of_month 

Rehearsal -----------------------------------------------
Cary          0.020000   0.000000   0.020000 (  0.025968)
Simple Lime   0.190000   0.000000   0.190000 (  0.192860)
Máté          0.460000   0.020000   0.480000 (  0.481839)
Gerry/Dan     0.810000   0.020000   0.830000 (  0.835931)
-------------------------------------- total: 1.520000sec

                  user     system      total        real
Cary          0.020000   0.000000   0.020000 (  0.024871)
Simple Lime   0.150000   0.000000   0.150000 (  0.150696)
Máté          0.390000   0.010000   0.400000 (  0.398637)
Gerry/Dan     0.710000   0.010000   0.720000 (  0.711155)