陣列GROUP_BY轉換日期

Question

我有一個數組：

array=[ 
{"name"=>"Henry Jones ", "Date"=>"2013-04-09 15:09:02", "Duration"=>"0:00:00", "Call Type"=>"Outgoing"}, 
{"name"=>"Barry Smith ", "Date"=>"2013-04-08 13:51:03", "Duration"=>"0:00:48", "Call Type"=>"Incoming"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-04 19:30:19", "Duration"=>"0:00:49", "Call Type"=>"Outgoing"}, 
{"name"=>"Alistair Morgan ", "Date"=>"2013-04-05 13:14:07", "Duration"=>"0:00:03", "Call Type"=>"Outgoing"}, 
{"name"=>"Quentin Blah", "Date"=>"2013-04-05 13:19:44", "Duration"=>"0:04:28", "Call Type"=>"Missed"}, 
{"name"=>"Quentin Blah", "Date"=>"2013-04-05 13:25:19", "Duration"=>"0:09:45", "Call Type"=>"Incoming"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-05 14:35:29", "Duration"=>"0:00:24", "Call Type"=>"Incoming"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-05 15:54:53", "Duration"=>"0:00:00", "Call Type"=>"Missed"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-06 16:21:20", "Duration"=>"0:00:47", "Call Type"=>"Outgoing"} 
] 

我想通過使用array_of_hashes.group_by {|d| d["Date"] }到GROUP_BY我可以GROUP_BY整個日期字符串日期字符串（例如，「2013年4月6日」）的日期然而這需要整個字符串。

如何我只是不計時間的日期組？ TIA

Answer 1

你幾乎沒有。由於日期是從時間用空格隔開，可以使用String#split來劃分從時間日期，然後Array#first來獲得日期：

array_of_hashes.group_by do |hash| 
    hash['Date'].split.first 
end 

使用IRB，你可以看到這是如何工作：

$ irb 
2.0.0p0 :001 > date = "2013-04-06 16:21:20" 
=> "2013-04-06 16:21:20" 
2.0.0p0 :002 > date.split 
=> ["2013-04-06", "16:21:20"] 
2.0.0p0 :003 > date.split.first 
=> "2013-04-06" 

Answer 2

Date的值只是一個字符串。幸運的是，它是一個行爲良好，固定寬度，可排序的字符串。前10個字符是我們想要的：

array=[ 
{"name"=>"Henry Jones ", "Date"=>"2013-04-09 15:09:02", "Duration"=>"0:00:00", "Call Type"=>"Outgoing"}, 
{"name"=>"Barry Smith ", "Date"=>"2013-04-08 13:51:03", "Duration"=>"0:00:48", "Call Type"=>"Incoming"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-04 19:30:19", "Duration"=>"0:00:49", "Call Type"=>"Outgoing"}, 
{"name"=>"Alistair Morgan ", "Date"=>"2013-04-05 13:14:07", "Duration"=>"0:00:03", "Call Type"=>"Outgoing"}, 
{"name"=>"Quentin Blah", "Date"=>"2013-04-05 13:19:44", "Duration"=>"0:04:28", "Call Type"=>"Missed"}, 
{"name"=>"Quentin Blah", "Date"=>"2013-04-05 13:25:19", "Duration"=>"0:09:45", "Call Type"=>"Incoming"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-05 14:35:29", "Duration"=>"0:00:24", "Call Type"=>"Incoming"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-05 15:54:53", "Duration"=>"0:00:00", "Call Type"=>"Missed"}, 
{"name"=>"Henry Jones ", "Date"=>"2013-04-06 16:21:20", "Duration"=>"0:00:47", "Call Type"=>"Outgoing"} 
] 

p array.group_by{|call| call["Date"][0..9]}