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

The new {santoku} package now offers a way to do this in the development version:

library(santoku)

set.seed(20200607)
x <- runif(20)

chop_evenly(x, 10, labels = lbl_intervals(fmt = percent))
#>  [1] [33.13%, 42.11%) [60.08%, 69.06%) [69.06%, 78.04%) [69.06%, 78.04%)
#>  [5] [87.02%, 96%]    [6.193%, 15.17%) [15.17%, 24.15%) [6.193%, 15.17%)
#>  [9] [33.13%, 42.11%) [6.193%, 15.17%) [87.02%, 96%]    [51.1%, 60.08%) 
#> [13] [42.11%, 51.1%)  [6.193%, 15.17%) [42.11%, 51.1%)  [6.193%, 15.17%)
#> [17] [6.193%, 15.17%) [69.06%, 78.04%) [78.04%, 87.02%) [87.02%, 96%]   
#> 9 Levels: [6.193%, 15.17%) [15.17%, 24.15%) ... [87.02%, 96%]
tab_evenly(x, 10, labels = lbl_intervals(fmt = scales::label_percent(accuracy = 0.1)))
#> x
#>  [6.2%, 15.2%) [15.2%, 24.2%) [33.1%, 42.1%) [42.1%, 51.1%) [51.1%, 60.1%) 
#>              6              1              2              2              1 
#> [60.1%, 69.1%) [69.1%, 78.0%) [78.0%, 87.0%) [87.0%, 96.0%] 
#>              1              3              1              3

^{Created on 2020-06-09 by the reprex package (v0.3.0)}

Answer 2

My package cutr does very similar things to @krlmlr's function (that I didn't know up until now).

cutf is just cut with a format_fun argument, and ... which is passed to format_fun, not cut as incut_format.

smart_cut has more features and different defaults :

devtools::install_github("moodymudskipper/cutr")
library(cutr)

x <- seq(0.1, 0.9, by = 0.2)
breaks <- seq(0, 1, by = 0.25)

cutf(x, breaks, format_fun = scales::percent)
# [1] (0%,25%]   (25%,50%]  (25%,50%]  (50%,75%]  (75%,100%]
# Levels: (0%,25%] (25%,50%] (50%,75%] (75%,100%]

smart_cut(x, breaks, format_fun = scales::percent,simplify = F, closed = "right")
# [1] [0%,25%]   (25%,50%]  (25%,50%]  (50%,75%]  (75%,100%]
# Levels: [0%,25%] < (25%,50%] < (50%,75%] < (75%,100%]

Hmisc::cut2 now also has a formatfun argument :

library(Hmisc)
Hmisc::cut2(x, breaks, formatfun = scales::percent)
# [1] [0%,25%)   [25%,50%)  [50%,75%)  [50%,75%)  [75%,100%]
# Levels: [0%,25%) [25%,50%) [50%,75%) [75%,100%]

Answer 3

Use gsub with some regex after multiplying your original data by 100:

gsub("([0-9.]+)","\\1%",levels(cut(x*100,breaks=10)))
 [1] "(0.449%,10.4%]" "(10.4%,20.3%]"  "(20.3%,30.2%]"  "(30.2%,40.2%]"  "(40.2%,50.1%]"  "(50.1%,60%]"    "(60%,69.9%]"    "(69.9%,79.9%]"  "(79.9%,89.8%]"  "(89.8%,99.7%]"

Answer 4

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%]"

Answer 5

A new answer to an oldish question.

You could use the label argument to pass a function to format the labels. I will use gsubfn and scales::percent

library(gsubfn)
library(scales)
pcut <- function(x) gsubfn('\\d\\.\\d+', function(x) percent(as.numeric(x)),xx)
d <- data.frame(x=runif(100))

ggplot(d,aes(x=x,y=seq_along(x))) + 
 geom_point(aes(colour = cut(x, breaks = 10))) + 
 scale_colour_brewer(name = 'x', palette = 'Spectral', label = pcut)

Answer 6

I have implemented cut_format() in version 0.2-3 of my kimisc package, version 0.3 is on CRAN now.

# devtools::install_github("krlmlr/kimisc")
x <- seq(0.1, 0.9, by = 0.2)

breaks <- seq(0, 1, by = 0.25)

cut(x, breaks)
## [1] (0,0.25]   (0.25,0.5] (0.25,0.5] (0.5,0.75] (0.75,1]  
## Levels: (0,0.25] (0.25,0.5] (0.5,0.75] (0.75,1]

cut_format(x, breaks, format_fun = scales::percent)
## [1] (0%, 25%]   (25%, 50%]  (25%, 50%]  (50%, 75%]  (75%, 100%]
## Levels: (0%, 25%] (25%, 50%] (50%, 75%] (75%, 100%]

It's still not perfect, passing the number of breaks (as in the original example) doesn't work yet.