Convert numbers to SI prefix

Question

Is there a R function (or any package) allowing to format numbers (integer) using standard unit prefix (Kilo, Mega etc ...), so

10 -> 10
100 -> 1K
0.01         


        

Answer 1

Slightly modified version to account for negative numbers :

f2si<-function (number, rounding=F, digits=ifelse(rounding, NA, 6)) 
{
mysign <- ""
if (number<0) {
    mysign <- "-"
}
number <- abs(number)
lut <- c(1e-24, 1e-21, 1e-18, 1e-15, 1e-12, 1e-09, 1e-06, 
    0.001, 1, 1000, 1e+06, 1e+09, 1e+12, 1e+15, 1e+18, 1e+21, 
    1e+24, 1e+27)
pre <- c("y", "z", "a", "f", "p", "n", "u", "m", "", "k", 
    "M", "G", "T", "P", "E", "Z", "Y", NA)
ix <- findInterval(number, lut)
if (ix>0 && ix

}