[R] create new variable: percentile value of variable in data frame
Jonathan Beard
jonathan.j.beard at gmail.com
Fri May 28 21:00:46 CEST 2010
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
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