On Aug 12, 2012, at 5:43 PM, Sachinthaka Abeywardana wrote:
Hi all,
It seems like I cannot use normal 'if' for data frames. What would
be the
best way to do the following.
if data$col1='high'
data$col2='H'
else if data$col1='Neutral'
data$col2='N'
else if data$col='low'
data$col2='L'
else
#chuch a warning?
Note that col2 was not an existing column and was newly assigned for
this
task.
Using arun's example, dat1:
dat1$col2 <- c("H","N", "L","warn")[
match(dat1$col1, c("low", "Neutral", "high"),
nomatch=4 )]
> dat1
col1 col2
1 high L
2 high L
3 high L
4 Neutral N
5 Neutral N
6 Neutral N
7 low H
8 low H
9 low H
10 low H
Nested ifelse constructions would be quite inefficient. I'm not even
sure that a 10-deep ifelse construction woul be acceptable to the
interpreter. At one point I thought I read something about a nesting
depth of 7 as being a limit. (But many years have passed since that
reading and it's possible it's just a manufactured memory or that the
limit has been raised.)
--
David Winsemius, MD
Alameda, CA, USA
______________________________________________
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.
