While collecting some corpus statistics, I came across a handy function in R that formats decimal into percentage expressions:

library(scales)
values = c(0.5, 0.01, 1e-4, 0.2734)
percent(values)
#[1] "50%" "1%"  "0%"  "27%"
# More verbose equivalent using sprintf
sprintf("%.0f%%", 100 * values)

The function is clearly most valuable if all values are in a range of 1 to 100 percent, as the documentation also suggests: “Multiply by one hundred and display percent sign.” [1] In contrast, the sprintf equivalent may be ‘configured’ such as to show more decimal places.

On Ubuntu, the enclosing package can be installed via

sudo apt-get install r-cran-scales

 References

• [1] scales package documentation

Edits

• 2017-05-03: Use library(scales) instead of library(ggplot2). Thanks to Vital!