R help - Apr 2009 - "reverse truncate" to extract only decimal values

hello there,

Is there a way of truncating in the opposite direction so as to retain only
the values to the right of the decimal??

i.e. rather than:
> trunc(39.5)
[1] 39

i would get something like:
> revtrunc(39.5)
[1] 0.5

I've been searching to no avail but I imagine there is a very simple
solution!
Tyler
-- 
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You could do something like this:
> revtrunc <- function(x) { x - floor(x) }
> revtrunc(39.5)
[1] 0.5

But note:
> revtrunc(-39.5)
[1] 0.5

I'm not sure what you'd want for negative numbers. One possibility:

revtrunc <- function(x) { sign(x) * (x - floor(x)) }
> revtrunc(39.5)
[1] 0.5
> revtrunc(-39.5)
[1] -0.5

Sarah

On Thu, Apr 16, 2009 at 5:30 PM, T.D.Rudolph <prairie.picker at gmail.com>
wrote:
>
> hello there,
>
> Is there a way of truncating in the opposite direction so as to retain only
> the values to the right of the decimal??
>
> i.e. rather than:
>> trunc(39.5)
> [1] 39
>
> i would get something like:
>> revtrunc(39.5)
> [1] 0.5
>
> I've been searching to no avail but I imagine there is a very simple
> solution!
> Tyler


-- 
Sarah Goslee
http://www.functionaldiversity.org

On Thu, Apr 16, 2009 at 10:30 PM, T.D.Rudolph <prairie.picker at
gmail.com> wrote:
> Is there a way of truncating in the opposite direction so as to retain only
> the values to the right of the decimal??
>
> i.e. rather than:
>> trunc(39.5)
> [1] 39
>
> i would get something like:
>> revtrunc(39.5)
> [1] 0.5
>
> I've been searching to no avail but I imagine there is a very simple
> solution!
revtrunc <- function(x) x-trunc(x)

Paul

On Thu, Apr 16, 2009 at 10:30 PM, T.D.Rudolph <prairie.picker at
gmail.com> wrote:
>
> hello there,
>
> Is there a way of truncating in the opposite direction so as to retain only
> the values to the right of the decimal??
>
> i.e. rather than:
>> trunc(39.5)
> [1] 39
>
> i would get something like:
>> revtrunc(39.5)
> [1] 0.5
>
> I've been searching to no avail but I imagine there is a very simple
> solution!
 'minus'?

 x - trunc(x) ?

Barry