[R] problem selecting rows meeting a criterion

Jim Bouldin jrbouldin at ucdavis.edu
Tue Aug 11 23:15:57 CEST 2009

Yes, thanks Steve and also to everyone else for helping me clear this up.
The issue was definitely the existence of other objects named X and Y that
I inadvertently referred to in my command statement.  Only when these
objects are removed AND the data frame in question is attached, will the
command I originally used work.  However, I see that it is much easier to
just use the subset function or perhaps the with function. Seems that R has
many painful lessons to teach. Thanks again.
Jim Bouldin

> This won't work in general, and is probably only working in this  
> particular case because you already have defined somewhere in your  
> workspace vars named X and Y.
> What you wrote above isn't taking the values X,Y from data$X and data 
> $Y, respectively, but rather from var X and Y defined elsewhere.
> Instead of doing data[X > Y], do:
> data[data$X > data$Y,]
> This should get you what you're expecting.
> Hopefully you're learning a slightly different lesson now :-)
> Does that clear things up at all?
> -steve
> --
> 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

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