From: Rob Biedenharn <Rob@...>
Date: 2007-03-20T03:18:29+09:00
Subject: Re: Sorting Dates and Times in an array


On Mar 19, 2007, at 1:25 PM, Rick DeNatale wrote:

> On 3/19/07, Paul <tester.paul@gmail.com> wrote:
>> Hi there.  I am having a bit of trouble trying to solve a particular
>> sorting problem with an array of data.
>>
>> Please bear with me for a moment regarding the setup of this problem.
>> I don't currently have any control over the input data.  I am just
>> trying to format the report of this data as per the requirement.
>>
>> I have the following sample array data to work with:
>> @date_array = [['2/22/07','1:03 pm'],['3/9/07','10:45 pm'],
>> ['3/1/07','1:52 pm'],['3/13/07','2:00 pm'],['2/28/07','10:45 am'],
>> ['3/5/07','4:00 pm'],['2/14/07','5:00 pm'],['3/9/07','10:18 am'],
>> ['3/13/07','11:15 am']]
>>
>> (The actual array contains more data, but this is good enough to work
>> on this problem.  BTW, date format = mm/dd/yy.)
>>
>> Requirement:
>> 1) Sort in descending order by Date (i.e. @date_array[x][0] )
>> 2) Sort in ascending order by Time (i.e. @date_array[x][1] )
>
> (Standard Library) objects are your friend.
>
> rick@frodo:/public/rubyscripts$ cat datesort.rb
> date_array = [['2/22/07','1:03 pm'],['3/9/07','10:45 pm'],
>  ['3/1/07','1:52 pm'],['3/13/07','2:00 pm'],['2/28/07','10:45 am'],
>  ['3/5/07','4:00 pm'],['2/14/07','5:00 pm'],['3/9/07','10:18 am'],
>  ['3/13/07','11:15 am']]
>
> p date_array.sort do |a, b|
>  ddiff = Date.parse(b[0],true) <=> Date.parse(a[0],true)
>  ddiff == 0 ? Time.parse(a[0]) <=> Time.parse(b[0]) : ddiff
> end


I think this was meant to be (note Time.parse(a[ 1 ]) not [0])

p date_array.sort do |a,b|
   (Data.parse(b[0],true) <=> Date.parse(a[0],true)).nonzero? ||  
Time.parse(a[1]) <=> Time.parse(b[1])
end

> rick@frodo:/public/rubyscripts$ ruby datesort.rb
> [["2/14/07", "5:00 pm"], ["2/22/07", "1:03 pm"], ["2/28/07", "10:45
> am"], ["3/1/07", "1:52 pm"], ["3/13/07", "11:15 am"], ["3/13/07",
> "2:00 pm"], ["3/5/07", "4:00 pm"], ["3/9/07", "10:18 am"], ["3/9/07",
> "10:45 pm"]]
> rick@frodo:/public/rubyscripts$
>
>
> -- 
> Rick DeNatale
>
> My blog on Ruby
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>
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>

Rob Biedenharn		http://agileconsultingllc.com
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