Skip to content

lapply() reccursively

2 messages · Kaveh Vakili, Saptarshi Guha

#
Hi all,

I was wondering whether it is possible to use the lapply() function
to alter the value of the input, something in the spirit of :

a1<-runif(100)
a2<-function(i){
  a1[i]<-a1[i-1]*a1[i];a1[i]
}
a3<-lapply(2:100,a2)

Something akin to a for() loop, but using the lapply() infrastructure.
I  haven't been able to get rapply() to do this.

The reason is that the "real" a2 function is a difficult function that only needs to be evaluated if the value of a1[i-1] meets some criteria.

Thanks in advance,
#
Never used rapply but with lapply the <<- operator might help
Saptarshi

On Oct 13, 2009, at 7:24 AM, Kaveh Vakili <kaveh.vakili at ulb.ac.be>  
wrote: