Format labels produced by cut() as percentages

Question

I need to apply cut on a continuous variable to show it with a Brewer color scale in ggplot2, as in Setting breakpoints for data with scale_fill_brewer() function i

Answer 1

Why not copy the code for cut.default and create your own version with modified levels? See this gist.

Two lines were changed:

Line 22: ch.br <- formatC(breaks, digits = dig, width = 1) changed to ch.br <- formatC(breaks*100, digits = dig, width = 1).

Line 29: else "[", ch.br[-nb], ",", ch.br[-1L], if (right) changed to else "[", ch.br[-nb], "%, ", ch.br[-1L], "%", if (right)

The rest is the same. And here it is in action:

library(devtools)
source_gist(4593967)

set.seed(1)
x <- runif(100)
levels(cut2(x, breaks=10))
#  [1] "(1.24%, 11%]"   "(11%, 20.9%]"   "(20.9%, 30.7%]" "(30.7%, 40.5%]" "(40.5%, 50.3%]"
#  [6] "(50.3%, 60.1%]" "(60.1%, 69.9%]" "(69.9%, 79.7%]" "(79.7%, 89.5%]" "(89.5%, 99.3%]"