How to round up to the nearest 10 (or 100 or X)?

Question

I am writing a function to plot data. I would like to specify a nice round number for the y-axis max that is greater than the max of the dataset.

Specifically, I would like a function foo that performs the following:

foo(4) == 5 foo(6.1) == 10 #maybe 7 would be better foo(30.1) == 40 foo(100.1) == 110  

I have gotten as far as

foo <- function(x) ceiling(max(x)/10)*10 

for rounding to the nearest 10, but this does not work for arbitrary rounding intervals.

Is there a better way to do this in R?

Answer 1

The plyr library has a function round_any that is pretty generic to do all kinds of rounding. For example

library(plyr) round_any(132.1, 10)               # returns 130 round_any(132.1, 10, f = ceiling)  # returns 140 round_any(132.1, 5, f = ceiling)   # returns 135