[R] create new variable: percentile value of variable in data frame

[Jonathan Beard]

Hello all,

Thanks in advance for you attention.
I would like to generate a third value that represents the quantile
value of a variable in a data frame.


# generating data

x <- as.matrix(seq(1:30))
y <- as.matrix(rnorm(30, 20, 7))
tmp1 <- cbind(x,y)
dat <- as.data.frame(tmp1)
colnames(dat) <- c("id", "score")
dat

#  finding percentiles of "score"

qs <- as.matrix(quantile(dat$score, type=3, probs = seq(0,1,.1)))
colnames(qs) <- c( "score")
qs

#  is there a way to put the quantile value for a value of 'score'
into a new variable,
#  such that the new data frame would have three variables: id, score
and q.score?

##  running R version 2.8.1 (2008-12-22) on Vista


Thanks so much!

-Jon