[R] subset and lme

Paul Lemmens P.Lemmens at nici.kun.nl
Wed Jun 16 16:48:03 CEST 2004

Hoi Todd,

--On woensdag 16 juni 2004 10:18 -0400 Todd Ogden <to166 at columbia.edu> 

> I'm puzzled by the following problem, which appears when
> attempting to run an analysis on part of a dataset:
> If I try:
>   csubset <- dat$Diagnosis==0
This just creates a vector of booleans that indicate (the row numbers) for 
which positions in dat Diagnosis==0.

>   cdat <- dat[dat$Diagnosis==0,]
This OTOH, uses the above vector to index the rows of dat, indeed selecting 
those rows from dat that have Diagnosis==0. This is assigned to cdat. You 
could have done

cdat <- dat[csubset,]

as well


Paul Lemmens
NICI, University of Nijmegen              ASCII Ribbon Campaign /"\
Montessorilaan 3 (B.01.05)                    Against HTML Mail \ /
NL-6525 HR Nijmegen                                              X
The Netherlands                                                 / \
Phonenumber    +31-24-3612648
Fax            +31-24-3616066

More information about the R-help mailing list