ruby-on-rails – 在两个日期之间获取月份名称

d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,'%Y%m').mon ] }
=> ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec","Jan","Dec"]

要么：

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ m[/dd$/ ].to_i ] }

这可能会快一点.

问题是年界.您必须跟踪年份和月份,而不仅仅是月份,否则在使用uniq删除日期时,您将删除所有重复的月份索引.我使用YYYYMM格式,以获得正确的粒度.

编辑：
让它变得更有趣.
我有一些代码味道一直困扰着我.我不喜欢使用Date.strftime和Date.strptime,所以我又针对这个问题进行了另一次运行：这里有两个运行速度更快的解决方案,以及基准测试：


输出看起来像：


有趣. “人民币”现在正在落后.从测试中拉出它并使环圈100x上升：


这使：


这基本上是两种新方式之间的关系.作为肛门,我会选择mb2,因为如果我这样做数百万次会更快一些,但你的里程可能会有所不同.
require 'benchmark'
require 'date'

d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

n = 100
Benchmark.bm(8) do |x|
  x.report('strptime') { n.times { (d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,'%Y%m').mon ] } } }
  x.report('regex')    { n.times { (d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ m[/dd$/ ].to_i           ] } } }
end

              user     system      total        real
strptime  3.
d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]
d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]0 0.020000 3.080000 ( 3.076614)
 regex 2.820000 0.010000 2.830000 ( 2.829366)
require 'benchmark'
require 'date'

def regex_months_between(d1,d2)
  d1,d2 = [d1,d2].map{ |d| Date.parse(d) }.minmax

  (d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ m[/dd$/ ].to_i ] }
end

def months_between1(d1,d2].map{ |d| Date.parse(d) }.minmax

  months = (d2.mon - d1.mon) + (d2.year - d1.year) * 12
  month_names = []
  months.times{ |m|
    month_names << Date::ABBR_MONTHNAMES[(d1 >> m).mon]
  }
  month_names << Date::ABBR_MONTHNAMES[d2.mon]
  month_names
end

def months_between2(d1,d2].map{ |d| Date.parse(d) }.minmax

  months = (d2.mon - d1.mon) + (d2.year - d1.year) * 12
  (d1.mon ... (d1.mon + months)).each_with_object(Date::ABBR_MONTHNAMES[d1.mon,1]) { |month_offset,month_names_array|
    month_names_array << Date::ABBR_MONTHNAMES[(d1 >> month_offset).mon]
  }
end

puts regex_months_between('jan 1 2011','dec 31 2012').join(',')
puts months_between1('jan 1 2011',')
puts months_between2('jan 1 2011',')

n = 100
Benchmark.bm(3) do |b|
  b.report('rmb') { n.times { regex_months_between('jan 1 2011','dec 31 2012') } }
  b.report('mb1') { n.times { months_between1('jan 1 2011','dec 31 2012') } }
  b.report('mb2') { n.times { months_between2('jan 1 2011','dec 31 2012') } }
endJan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec,Jan,Dec
Jan,Dec
        user     system      total        real
rmb  2.810000   0.010000   2.820000 (  2.820732)
mb1  0.
d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]

0 0.000000 0.
d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]

0 ( 0.057763)
 mb2 0.
d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]0 ( 0.057112)
n = 10_000
Benchmark.bm(3) do |b|
  b.report('mb1') { n.times { months_between1('jan 1 2011','dec 31 2012') } }
enduser     system      total        real
mb1  5.570000   0.
d1 = Date.parse('jan 1 2011')
d2 = Date.parse('dec 31 2012')

(d1..d2).map{ |m| m.strftime('%Y%m') }.uniq.map{ |m| Date::ABBR_MONTHNAMES[ Date.strptime(m,"Dec"]0 5.630000 ( 5.615789)
 mb2 5.570000 0.040000 5.610000 ( 5.611323)