[R] Index of a Loop Variable?
Gabor Grothendieck
ggrothendieck at myway.com
Wed Apr 7 06:29:37 CEST 2004
>
You could define the utility function iter:
iter <- function(x) mapply( x, seq(along=x),
FUN=function(x,i)list(x=x,i=i), SIMPLIFY=F )
and use it like this to loop over seq(5,50,5) and 1:10 simultaneously:
> for(idx in iter(seq(5,50,5))) with(idx, cat(x,i,"\n"))
5 1
10 2
15 3
20 4
25 5
30 6
35 7
40 8
45 9
50 10
Jim Java writes--
Hi Everyone:--
Is it possible, within a for loop not explicitly using whole-number
indexing, to find out the index value of the loop variable within the
vector or list that's being looped through? For example, in --
x <- seq(5, 50, by=5)
index.in.x <- 1
for (i in x) {
cat(paste(" index of i-value ", i, " within x: ", index.in.x, sep=""),
fill=T)
index.in.x <- index.in.x + 1
}
-- is it in general possible to get values of "index.in.x" without
making it a count variable, as above?
Thank you.
-- Jim Java
More information about the R-help
mailing list