you can also look at subset,
my.data.frame <- data.frame(a=rnorm(10),
b=factor(sample(letters[1:4], 10, replace=T)))
str(my.data.frame)
my.data.frame[my.data.frame$b == "a", ]
subset(my.data.frame, b == "a")
by the way, it is probably safer not to use "data" as a variable name
as it is also a function.
Hope this helps,
baptiste
On 13 Jan 2009, at 09:33, Dimitris Rizopoulos wrote:
have a look at ?"[.data.frame"; what you need is the following:
dat <- data.frame(a = rbinom(20, 1, 0.5), x = rnorm(20), y =
rnorm(20))
dat
dat[dat$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@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
______________________________________________
R-help@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.
_____________________________
Baptiste Auguié
School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK
Phone: +44 1392 264187
http://newton.ex.ac.uk/research/emag
______________________________________________
R-help@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.
