R help - Mar 2011 - sum of digits or how to slice a number into its digits

Dear R colleagues,

I face a seemingly simple problem I couldn't find a solution for myself
so far:

I have to sum the digits of numbers. Example: 1010 ->2 100100110 -> 4
Unfortunately there seems not to be a function for this task. So my idea
was to use sum(x) for it. But I did not figure out how to slice a number
to a vector of its digits. Example (continued from above): 1010 ->
c(1,0,1,0)  100100110 -> (1,0,0,1,0,0,1,1,0).

Does anyone know either a function for calculating the sum of the digits
of a bumber, or how to slice a number into a vector of its digits as
described above?

I'd appreciate any kind of help very much!
Thanx in advance and greetings from cloudy Munich,
Felix

one way is using function strsplit(), e.g.,

x <- c("100100110", "1001001", "1101",
"00101")
sapply(strsplit(x, ""), function (x) sum(x == 1))


I hope it helps.

Best,
Dimitris


On 3/4/2011 2:18 PM, drflxms wrote:
> Dear R colleagues,
>
> I face a seemingly simple problem I couldn't find a solution for myself
> so far:
>
> I have to sum the digits of numbers. Example: 1010 ->2 100100110 -> 
4
> Unfortunately there seems not to be a function for this task. So my idea
> was to use sum(x) for it. But I did not figure out how to slice a number
> to a vector of its digits. Example (continued from above): 1010 ->
> c(1,0,1,0)  100100110 ->  (1,0,0,1,0,0,1,1,0).
>
> Does anyone know either a function for calculating the sum of the digits
> of a bumber, or how to slice a number into a vector of its digits as
> described above?
>
> I'd appreciate any kind of help very much!
> Thanx in advance and greetings from cloudy Munich,
> Felix
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/

Hi,

Here is the best I've found:
x <- 100100110
sum(as.numeric(unlist(strsplit(as.character(x), split=""))))

It first converts x to character, then splits every character, unlist()s 
the results, then reconverts to numeric and sums it.

HTH,
Ivan

Le 3/4/2011 14:18, drflxms a ?crit :
> Dear R colleagues,
>
> I face a seemingly simple problem I couldn't find a solution for myself
> so far:
>
> I have to sum the digits of numbers. Example: 1010 ->2 100100110 -> 
4
> Unfortunately there seems not to be a function for this task. So my idea
> was to use sum(x) for it. But I did not figure out how to slice a number
> to a vector of its digits. Example (continued from above): 1010 ->
> c(1,0,1,0)  100100110 ->  (1,0,0,1,0,0,1,1,0).
>
> Does anyone know either a function for calculating the sum of the digits
> of a bumber, or how to slice a number into a vector of its digits as
> described above?
>
> I'd appreciate any kind of help very much!
> Thanx in advance and greetings from cloudy Munich,
> Felix
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. S?ugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

**********
http://www.for771.uni-bonn.de
http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php