How do I round a float to a specified number of significant digits in Ruby?

Question

It would be nice to have an equivalent of R\'s signif function in Ruby.

For example:

>> (11.11).signif(1)
10
>> (22.22).signif(2)
22
>         


        

Answer 1

@Blou91's answer is nearly there, but it returns a string, instead of a float. This below works for me:

(sprintf "%.2f", 1.23456).to_f

So as a function,

def round(val, sig_figs)
  (sprintf "%.#{sig_figs}f", val).to_f
end