[R] Sorting data.frame and again sorting within data.frame

[Jeff Newmiller]

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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Sent from my phone. Please excuse my brevity.

David Winsemius <dwinsemius at 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