[R] indexing question

[Dimitris Rizopoulos]

have a look at ?"[.data.frame"; what you need is the following:

dat <- data.frame(a = rbinom(20, 1, 0.5), x = rnorm(20), y = rnorm(20))

dat
dat[dat$a == 1, ]


I hope it helps.

Best,
Dimitris


Bunny, lautloscrew.com wrote:
> Hi all,
> 
> i have a pretty easy indexing question, at least i believe so. The main 
> reason i post it here, is that brackets and $ are hard to google.
> 
> How do I index correctly, if i just want to display the whole dataset 
> conditioned on the fact that some particular column equals one.
> 
> I know i can do something like:   data$somecolumn[data$particularcol 
> ==1] . That will show all "some column" values where the particular 
> column is 1.
> Unfortunately something like : data[data$particularcol ==1] does not 
> work to get the whole matrix.
> 
> is there some easy way except the % in % stuff ?
> 
> Thx in advance
> 
> ______________________________________________
> 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.
> 

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014