R change decimal place without round off

Question

> signif(1.89,digits=2)
[1] 1.9

I\'d like to have 1.8

Answer 1

This is a bit clunky, but it will work and keep everything numeric:

x <- 1.829380

trunc.dec <- function(x,n) {
  floor(x*10^n)/10^n
}

Result:

trunc.dec(x,1)
#[1] 1.8
trunc.dec(x,2)
#[1] 1.82
trunc.dec(x,3)
#[1] 1.829
trunc.dec(x,4)
#[1] 1.8293