[R] element wise opertation between a vector and a list

Moshe Olshansky m_olshansky at yahoo.com
Tue Sep 4 01:23:08 CEST 2007


Hi,

Getting your e is not a problem:

> a<- list(c(1,3),c(1,2),c(2,3))
>  b<-c(10,20,30)
> aa<-matrix(unlist(a),nrow=2)
> ee<-aa+rbind(b,b)
> e<-apply(ee,2,"sum")
> e
[1] 24 43 65
> 

But this will not work if different list members have
different number of elements.

--- Yongwan Chun <ywchun at gmail.com> wrote:

> I want to try to get a result of element wise
> addition between a
> vector and a list. It can be done with "for
> statement." In order to
> reducing computing time, I have tried to avoid "for
> state." If anybody
> give me an idea, I would apprecite it much.
> 
> for example, with a & b as below lines,
> 
> a<- list(c(1,3),c(1,2),c(2,3))
> b<-c(10,20,30)
> 
> I would like to have a list (like "d") or a vector
> (like "e") as below.
> 
>
d<-list(c((1+10),(3+10)),c((1+20),(2+20)),c((2+30),(3+30)))
> e<- c((1+10)+(3+10),(1+20)+(2+20),(2+30)+(3+30))
> 
> Thanks,
> 
> 
> Yongwan Chun
> 
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