[R] Removing

David Winsemius dwinsemius at comcast.net
Thu Mar 12 20:38:07 CET 2009


On Mar 12, 2009, at 3:02 PM, David Winsemius wrote:

> True, I suppose. The specification from Ma could have been more  
> explicit. Should she want to only have duplicates in sequence, then  
> perhaps the use of construction within the rle function would be  
> useful.
>
> act2[ act2$Rep[-1] != act2$Rep[-length(act2$Rep)], ]
>
>         Date    Dtime Hour Min Second               Rep
> 51 2006-02-22 14:52:18   14  52     18  useractivity_act
> 57 2006-02-22 14:52:51   14  52     51                 4
> 58 2006-02-22 14:52:52   14  52     52                 3
> 60 2006-02-22 14:54:42   14  54     42 useractivity_idle
>
> Which turns out on examination to be isomorphic to Gabor's earlier  
> efforts.

Almost ... but not quite. The addition of a TRUE to that logical vecor  
(as in Bill Dunap's posting as well as Gabor's solution) is needed to  
keep this from failing in some instances, although this test case did  
not expose the flaw.

act2[c(TRUE, act2$Rep[-1] != act2$Rep[-length(act2$Rep)]), ]

>
> -- 
> David Winsemius
>
>
> On Mar 12, 2009, at 2:31 PM, Patrick Burns wrote:
>
>> Simpler, but maybe wrong.  Not duplicated
>> was my first response as well, but then I began
>> wondering if the question implied globally
>> duplicated or duplicated within subgroups.
>>
>>
>> Patrick Burns
>> patrick at burns-stat.com
>> +44 (0)20 8525 0696
>> http://www.burns-stat.com
>> (home of "The R Inferno" and "A Guide for the Unwilling S User")
>>
>> David Winsemius wrote:
>>> Much simpler would be:
>>>
>>> act2[!duplicated(act2$Rep),]   #use the negation of the duplicated  
>>> function on $Rep and indexing
>>>
>>>        Date    Dtime Hour Min Second               Rep
>>> 51 2006-02-22 14:52:18   14  52     18  useractivity_act
>>> 52 2006-02-22 14:52:18   14  52     18                 4
>>> 58 2006-02-22 14:52:52   14  52     52                 3
>>> 60 2006-02-22 14:54:42   14  54     42 useractivity_idle
>>>
>>> Cannot reproduce the blank line though.
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
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> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT




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