[R] modifying arrays within functions

Konrad BLOCHER kb25532 at sgh.waw.pl
Tue Feb 5 17:32:26 CET 2008


Got it Thanks

> On Tuesday 05 February 2008 (16:51:41), Konrad BLOCHER wrote:
>> Hi,
>>
>> I'm pretty new to R and seem to be having difficulties with writing a
>> function that would change an array and keep the change after the
>> function
>> finishes its work.
>>
> It seems you want this:
>
> X<-array(1,dim=c(2,2))
> addition<-function(a){
> 	X[1,1] <<- X[1,1]+a # not '='
> }
> addition(1)
> X
>
>
>      [,1] [,2]
> [1,]    2    1
> [2,]    1    1
>
>
> Nevertheless I would advise against writing and using functions that
> have side effects outside their scope.
> It is in general dangerous.
>
> Best,
>
> Martin
>
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