dear experts,
I am new to R and am trying to compute a vector y from a vector x where :
y[i] = sign(x[j]-x[i])*(j-i) with j the first index after i where
abs(x[j]-x[i]) > to a given step
y[i] is 0 if there is no such j
I can write this in R as follows
for(i in 1:length(x)) {
y[i]=0
for(j in i:length(x)) {
if (abs(x[j]-x[i]) > step) {
y[i]=sign(x[j]-x[i])*(j-i)
break;
}
}
}
but I wonder if there is a more efficient way to write this. I understand
explicit looping can often be avoided in R using vector notation.
Thanks for your help
--
View this message in context:
http://www.nabble.com/newbie%3Alooking-for-an-efficient-way-to-compute-distance-vector-tp15045583p15045583.html
Sent from the R help mailing list archive at Nabble.com.
______________________________________________
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.
