Ruby按日期计算项目
我有一系列日期,例如
Fri Jan 28 10:13:19 UTC 2011 Thu Jan 27 16:57:59 UTC 2011 Thu Jan 27 16:41:21 UTC 2011 Wed Jan 26 09:20:48 UTC 2011 Mon Jan 24 16:19:48 UTC 2011 Fri Jan 21 11:45:34 UTC 2011 Fri Jan 21 11:42:19 UTC 2011
如何对它们进行分组,使得输出与每天的项目数一样为哈希值:
Friday 28 => 1 Thursday 27 => 2 Wednesday 26 => 1 Monday 24 => 1 Friday 21 => 2
或者,将kurumi的解决方案更加冗长并使用Jimmy的strftime:
histogram = dates.inject(Hash.new(0)) do |hist, date| hist[date.strftime('%A %d')] += 1 hist end.sort_by{|date, count| date.split(' ').last}.reverse
给我们:
Friday 28: 1 Thursday 27: 2 Wednesday 26: 1 Monday 24: 1 Friday 21: 2
好?
@things.group_by {|thing| thing.strftime "%A %d" }.each do |key, group| puts "#{key} => #{group.size}" end
%A
是完整的工作日名称, %d
是该月的日期
我目前无法测试,但我认为它会起作用。
s=a.inject(Hash.new(0)) do |h,y| z=y.split h[ z[0]+z[2] ]+=1 h end