How to replace outliers with the 5th and 95th percentile values in R

Question

I\'d like to replace all values in my relatively large R dataset which take values above the 95th and below the 5th percentile, with those percentile values

Answer 1

You can do it in one line of code using squish():

d2 <- squish(d, quantile(d, c(.05, .95)))

---

In the scales library, look at ?squish and ?discard

#--------------------------------
library(scales)

pr <- .95
q  <- quantile(d, c(1-pr, pr))
d2 <- squish(d, q)
#---------------------------------

# Note: depending on your needs, you may want to round off the quantile, ie:
q <- round(quantile(d, c(1-pr, pr)))

example:

d <- 1:20
d
# [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20


d2 <- squish(d, round(quantile(d, c(.05, .95))))
d2
# [1]  2  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 19