[R] sum variable as long condition is true
Shubha Vishwanath Karanth
shubhak at ambaresearch.com
Tue Oct 23 14:08:59 CEST 2007
rowsum(c$a,c$b)
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of marcg
Sent: Tuesday, October 23, 2007 5:22 PM
To: r-help at stat.math.ethz.ch
Subject: [R] sum variable as long condition is true
Hello R
For expierienced user, the following problem will be easy to solve:
a<-c(0,1,0,1,0,2,3,4,3,2)
b<-c(3,3,3,4,4,4,7,7,7,10)
c<-data.frame(a,b)
Data Frame c contains tow colums. I would like to sum up all values in a
as long as b stays the same:
sum(a[which(b==1)])
does this, but i have to manually put in b
then i tryied st like this, but i canno't save it properly
for (i in 0:max(b)){
i<-sum(a[which(b==i)])
}
i tried to figure out, how tapply works, but neither
thanks alot
marc
--
______________________________________________
R-help at 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.
More information about the R-help
mailing list