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

[Charles C. Berry]

On Wed, 5 Sep 2007, Greg Snow wrote:

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


or
 	sapply( a, sum ) + b * sapply( a, length )

or even

 	sapply( a, sum ) + b * 2

if all list components in 'a' are of length 2.


Then there are the do.call( cbind , a ) incantations.

Chuck

>
> 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.
>>
>
> ______________________________________________
> 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.
>

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901