More elegant magnitude method

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Re: [R] More elegant magnitude method

David Winsemius 

to:

Jonathan P Daily

12/07/2010 02:50 PM

Cc:

r-help


On Dec 7, 2010, at 2:43 PM, Jonathan P Daily wrote:

I have a need to find the order of number to get a scaling parameter 
as a
power of 10. I have a function that works *so far*, but it is ugly and
probably buggy. In the interest of avoiding code-based outliers in my
data, I thought I would ask if anyone here has a better way.

scl <- function(x){

+ length(charToRaw(format(trunc(x), scientific = F)))-1}

a <- 123456789
b <- 1E15
c <-  12.345
scl(a)

[1] 8

scl(b)

[1] 15

scl(c)

[1] 1

scl<- function(x) trunc(log(x,10))

 > scl(a)

[1] 8

 >
 > scl(b)

[1] 15

 >
 > scl(c)

[1] 1

Seems mathematically clearer.
-- 
David Winsemius, MD
West Hartford, CT