[R] Selecting all rows of factors which have at least one positive value?

[Patrizio Frederic]

or the exactly equivalent form:

x[x$X1 %in% unique(x[x$X2>0,"X1"]), ]

Patrizio

2009/4/2 Nutter, Benjamin <NutterB at ccf.org>:
> x <-
> data.frame(matrix(c(rep(11,4),rep(12,3),rep(13,3),rep(0,3),1,rep(0,4),re
> p(1,2)),ncol=2))
>
> id.keep <- unique(subset(x,X2>0)$X1)
>
> x2 <- subset(x,X1 %in% id.keep)
>
> x2
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Stephan Lindner
> Sent: Thursday, April 02, 2009 11:26 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Selecting all rows of factors which have at least one
> positive value?
>
> Dear all,
>
> I'm trying to select from a dataframe all rows which correspond to a
> factor (the id variable) for which there exists at least one positive
> value of a certain variable. As an example:
>
> x <-
> data.frame(matrix(c(rep(11,4),rep(12,3),rep(13,3),rep(0,3),1,rep(0,4),re
> p(1,2)),ncol=2))
>
>> x
>
>
>   X1 X2
> 1  11  0
> 2  11  0
> 3  11  0
> 4  11  1
> 5  12  0
> 6  12  0
> 7  12  0
> 8  13  0
> 9  13  1
> 10 13  1
>
>
> and I want to select all rows pertaining to factor levels of X1 for
> which exists at least one "1" for X2. To be clear, I want rows 1:4
> (since there exists at least one observation for X1==11 for which
> X2==1) and rows 8:10 (likewise).
>
> It is easy to obtain the corresponding factor levels (i.e.,
> unique(x$X1[x$X2==1])), but I got stalled selecting the corresponding
> rows. I tried grep, but then I have to loop and concatenate the
> resulting vector. Any ideas?
>
>
> Thanks a lot!
>
>
>        Stephan
>
>
>
>
>
> --
> -----------------------
> Stephan Lindner
> University of Michigan
>
> ______________________________________________
> 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.
>
>
> ===================================
>
> P Please consider the environment before printing this e-mail
>
> Cleveland Clinic is ranked one of the top hospitals
> in America by U.S. News & World Report (2008).
> Visit us online at http://www.clevelandclinic.org for
> a complete listing of our services, staff and
> locations.
>
>
> Confidentiality Note:  This message is intended for use\...{{dropped:13}}
>
> ______________________________________________
> 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.
>