Hi Sean,
Comment in line below.
On Thu, Oct 22, 2009 at 5:39 PM, Sean MacEachern <sean.maceach at
gmail.com> wrote:> Hi,
>
> I'm running into a problem subsetting a data frame that I have never
> encountered before:
>
>> dim(chkPd)
> [1] 3213 ? ?6
>
>> df = head(chkPd)
>> df
> ? ? ? ? ? ? ? PN ? ? ? ?WB ? ? ?Sire ? ? Dam ? MG SEX
> 601 ? ? ?1001 ?715349 ? 61710 ? 61702 ? 67 ? ?F
> 969 ?1001_1 ?511092 616253 615037 168 ? ?F
> 986 ?1002_1 ?511082 616253 623905 168 ? ?F
> 667 ? ? ?1003 ?715617 ? 61817 ? 61441 ? 67 ? ?F
> 1361 1003_1 510711 635246 627321 168 ? ?F
> 754 ? ? ? 1004 715272 ? 62356 ? 61380 ?67 ? ? F
>
>
>> dfb = chkPd[df$PN,]
>> dfb
> ? ? ? ? ? ?PN ? ? WB ? Sire ? ?Dam ?MG ?SEX
> 1001 ? ?2114_1 510944 616294 614865 168 ? ?M
> NA ? ? ? ?<NA> ? ? NA ? <NA> ? <NA> ?NA <NA>
> NA.1 ? ? ?<NA> ? ? NA ? <NA> ? <NA> ?NA <NA>
> 1003 ? ?1130_1 510950 616294 619694 168 ? ?F
> NA.2 ? ? ?<NA> ? ? NA ? <NA> ? <NA> ?NA <NA>
> 1004 2221-SHR2 510952 616294 619694 168 ? ?M
>
>
> I'm not sure why I'm getting this behaviour? By sub-setting the
> original data frame by PN I seem to be pulling out row numbers?
> Therefore I am only getting results where PN is less than the
> dimensions of the original data frame and of course nothing where PN
> has _ in the id. I have also tried using subset but haven't had any
> luck with that either.
That is the documented behavior as far as I can tell. See
?"[.data.frame"
Maybe my brain is going soft at the end of a long day, but I can't
tell what you're trying to do. Can you clarify?
-Ista
>
>
>>dfb = subset(chkPd, PN==df$PN)
> Warning message:
> In PN == df$PN :
> ?longer object length is not a multiple of shorter object length
>
> I wasn't aware that both the larger data frame had to be a multiple of
> the object you were sub-setting . In any case I would appreciate any
> insight into what I may be doing wrong.
>
> Cheers,
>
> Sean
>
>
>> sessionInfo()
> R version 2.9.1 (2009-06-26)
> i386-apple-darwin8.11.1
>
> locale:
> en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
>
> attached base packages:
> [1] splines ? stats ? ? graphics ?grDevices utils ? ? datasets ?methods ?
base
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org