On Tue, 26 Aug 2008, Chris Oldmeadow wrote:
Hi,
I have a vector of start positions, and another vector of stop positions,
eg start<-c(1,20,50)
stop<-c(7,25,53)
Is there a quick way to create a sequence from these vectors?
new<-c(1,2,3,4,5,6,7,20,21,22,23,24,25,50,51,52,53)
Vectorize the process.
start2 <- rep( start, stop-start+1 )
lens <- stop-start+1
offset <- rep(cumsum(c( 0, lens )),c( lens ,0 ))
seq(along=offset)-offset+start2-1
[1] 1 2 3 4 5 6 7 20 21 22 23 24 25 50 51 52 53
HTH,
Chuck
the way Im doing it at the moment is
pos<-seq(start[1],stop[1])
for (i in 2:length(start)){
new<-seq(start[i],stop[i])
pos<-c(pos,new)
}
This works on small data, but its very inefficient on large vectors, and is
taking forever!
Anybody no a better way?
many thanks,
Chris
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Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:[EMAIL PROTECTED] UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
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