On 2011-09-02 05:16, Anna Dunietz wrote:
Hi All!
Please find code and the respective lists below. My problem: I specify the
case that lilwin[[p]] is not an NA and want the code found in iwish to be
returned ONLY for that case. Why do I get a list of length 2 (and why is
NULL the first element)? I understand that the code below is quite
senseless. I have run into a problem while working on a large project and
wanted to simplify it in order for it to be more understandable and
accessible. If I should not be using the if function, please let me know
what I should be doing instead. I know that I must use the for function for
my project. The thing I most want to understand is how, after specifying a
certain condition, one may save certain data that occurs when that condition
is met. I hope I have been clear enough!
Thank you very much for your help!
Anna
biglist<-list(a=1:4,b=2:6)
lilwin<-list(x=NA,y=2)
lilloss<-list(m=1,n=3)
biglist$a
[1] 1 2 3 4
$b
[1] 2 3 4 5 6
lilwin$x
[1] NA
$y
[1] 2
lilloss$m
[1] 1
$n
[1] 3
iwish<-list()
for(p in 1:length(biglist)){
if(is.na(lilwin[[p]])==F) iwish[p]<-list(biglist[[p]][lilwin[[p]]])
}
iwish[[1]]
NULL
[[2]]
[1] 3
Jean has given you one fix. Here's another (see ?'c'):
iwish<-list()
for(p in seq_along(biglist)){
if(!is.na(lilwin[[p]]))
iwish <- c(iwish, biglist[[p]][lilwin[[p]]])
}
BTW, it's not a good idea to use 'F' instead of FALSE and the
negation operator is usually a better way to test.
Peter Ehlers
[[alternative HTML version deleted]]
______________________________________________
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.
______________________________________________
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.
