R help - Sep 2007 - 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

Hi

 mapply("+", a, b)

Regards
Petr

r-help-bounces at stat.math.ethz.ch napsal dne 03.09.2007 08:36:10:
> 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
> 
> ______________________________________________
> R-help at stat.math.ethz.ch 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.

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
> 
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>

> ?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
> 
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>