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.

Specif

Answer 1

I think your code just works great with a small modification:

foo <- function(x, round=10) ceiling(max(x+10^-9)/round + 1/round)*round

And your examples run:

> foo(4, round=1) == 5
[1] TRUE
> foo(6.1) == 10            #maybe 7 would be better
[1] TRUE
> foo(6.1, round=1) == 7    # you got 7
[1] TRUE
> foo(30.1) == 40
[1] TRUE
> foo(100.1) == 110
[1] TRUE
> # ALL in one:
> foo(c(4, 6.1, 30.1, 100))
[1] 110
> foo(c(4, 6.1, 30.1, 100), round=10)
[1] 110
> foo(c(4, 6.1, 30.1, 100), round=2.3)
[1] 101.2

I altered your function in two way:

• added second argument (for your specified X )
• added a small value (=1e-09, feel free to modify!) to the max(x) if you want a bigger number