Application of "merge" and "within"
Notice that within-group processing is intended. I'd try
first <- function(x)x[1]
s <- within(q, {bl <- ave(b, paste(G,a), FUN=first); db <- b - bl})
Or perhaps
q <- within(q, Ga <- paste(G,a))
tbl <- with(q, tapply(b, Ga, first))
s <- within(q, {bl <- tbl[Ga]; db <- b - bl})
-pd
On 28 May 2016, at 22:53 , Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
On 27/05/2016 7:00 PM, Santosh wrote:
Dear Rxperts! Is there a way to compute relative values.. using within().. function? Any assistance/suggestions are highly welcome!! Thanks again, Santosh...
___________________________________________________________________
A sample dataset and the computation "outside" within() function is shown..
q <- data.frame(GL = rep(paste("G",1:3,sep = ""),each = 50),
G = rep(1:3,each = 50),
D = rep(paste("D",1:5,sep = ""),each = 30),
a = rep(1:15,each = 10),
t = rep(seq(10),15),
b = round(runif(150,10,20)))
r <- subset(q,!duplicated(paste(G,a)),sel=c(G,a,b))
names(r)[3] <- "bl"
s <- merge(q,r)
s$db <- s$b-s$bl
head(s,5)
G a GL D t b bl db
1 1 1 G1 D1 1 13 13 0
2 1 1 G1 D1 2 16 13 3
3 1 1 G1 D1 3 19 13 6
4 1 1 G1 D1 4 12 13 -1
5 1 1 G1 D1 5 19 13 6
Just use s <- within(s, db <- b - bl) Duncan Murdoch
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