Dear Sir,
Thanks a lot for your valuable input and guidance.
Regards
Katherine
--- On Mon, 15/4/13, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote:
From: Jeff Newmiller <jdnew...@dcn.davis.ca.us>
Subject: Re: [R] Sorting data.frame and again sorting within data.frame
To: "David Winsemius" <dwinsem...@comcast.net>, "Katherine Gobin"
<katherine_go...@yahoo.com>
Cc: r-help@r-project.org
Date: Monday, 15 April, 2013, 5:33 PM
Yes, that would be because she converted to Date on the fly in her example, and
so apparently did not need this reminder.
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David Winsemius <dwinsem...@comcast.net> wrote:
>
>On Apr 14, 2013, at 11:01 PM, Katherine Gobin wrote:
>
>> Dear R forum,
>>
>> I have a data.frame as defied below -
>>
>> df = data.frame(names = c("C", "A", "A", "B", "C", "B", "A", "B",
>"C"), dates = c("4/15/2013", "4/13/2013", "4/15/2013", "4/13/2013",
>"4/13/2013", "4/15/2013", "4/14/2013", "4/14/2013","4/14/2013" ),values
>= c(10, 31, 31, 17, 11, 34, 102, 47, 29))
>>
>>> df
>> names dates values
>> 1 C 4/15/2013 10
>> 2 A 4/13/2013 31
>> 3 A 4/15/2013 31
>> 4 B 4/13/2013 17
>> 5 C 4/13/2013 11
>> 6 B
>> 4/15/2013 34
>> 7 A 4/14/2013 102
>> 8 B 4/14/2013 47
>> 9 C 4/14/2013 29
>>
>> I need to sort df first on "names" in increasing order and then
>further on "dates" in a decreasing order i.e. I need
>>
>
>So far no one has pointed out that these are not really "Dates" in the
>R sense and will not sort correctly if any of the proposed methods are
>applied to sequences that extend beyond6 months, i.e, until October
>forward. You would be advised to convert to real Date-classed
>variables.
>
>?strptime
>?as.Date
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