Ruby按日期计算项目 [英] Ruby count items by date

问题描述

我有一个数组，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 
  

将它们分组，使得输出与每天的项目数量一样为哈希：

  Friday 28 => 1 
星期四27 => 2 
星期三26 => 1 
星期一24 => 1 
星期五21 => 2 
  

解决方案

或者，将kurumi的解决方案更详细地使用， 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：

 星期五28：1 
星期四27：2 
星期三26：1 
星期一24：1 
星期五21：2 
  

确定？

I have an array of dates e.g.

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

How can I group them so the output is as hash with the count of items each day:

Friday 28 => 1
Thursday 27 => 2
Wednesday 26 => 1
Monday 24 => 1
Friday 21 => 2

解决方案

Or, to put kurumi's solution more verbosely and using Jimmy's 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

give us:

Friday 28: 1
Thursday 27: 2
Wednesday 26: 1
Monday 24: 1
Friday 21: 2

OK?

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