[R] Extract subset of rows

[Steve Lianoglou]

Hi,

On Fri, Dec 17, 2010 at 10:22 AM, John Haart <another83 at me.com> wrote:
> Hi all,
>
> Sorry i forgot to mention there a species present in one matrix not in the other hence the problem i.e matrix 1 may have species E which isnt present in matrix 2 and matrix 2 may have species F not present in matrix 1.
>
> Sorry for the lack of clarification in the original post!

This still isn't a problem, you can choose to include the results that
appear in one data.frame vs. the other by playing with the all, all.x,
all.y parameters in the merge function ...

-steve

>
> John
> On 17 Dec 2010, at 15:19, John Haart wrote:
>
> Hi,
>
> I have two matrices with a common field = species what i want to do is make a matrix that combines the data held in the other two based on the species name.
>
> I.e ( simple example)
>
> Matrix 1 - monocot
>
> SPECIES V1
>
> A                       2
> B                       3
> C                       4
> D                       5
>
> Matrix 2 - PCAresults
>
> SPECIES V2
>
> A                       0.2
> B                       0.3
> C                       4.1
> D                       3.2
>
> matrix 3 - What i want
>
> SPECIES V1      V2
>
> A                       2       0.2
> B                       3       0.3
> C                       4       4.1
> D                       5       3.2
>
>
>
> my attempt has been this
>
> test <-monocot[which(monocot$SPECIES%in%PCAresults$SPECIES),]
>
> But this returns matrix with only those found in each but doesn't "import" the data from PCAresults
>
> Any help would be greatly appreciated
>
> John
>
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> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Steve Lianoglou
Graduate Student: Computational Systems Biology
 | Memorial Sloan-Kettering Cancer Center
 | Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact