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

Greg Snow Greg.Snow at intermountainmail.org
Wed Sep 5 19:24:14 CEST 2007


> ?mapply
> mapply('+', a, b, SIMPLIFY=FALSE)
> colSums(mapply('+', a, b))

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 
 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Yongwan Chun
> Sent: Monday, September 03, 2007 12:36 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] element wise opertation between a vector and a list
> 
> 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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