R help - Mar 2010 - Create vectors from a vector

Dear all,

I would like to create a number of vectors which contain the the first n
elements of an existing vector. 
For example I have the vectors vnk (200x1) and vro(200x1) and I want to
create 200 vectors that contain the 1st till the n_th element of the vectors
and thus be able to create a vector s with 200 elements which are the
product of all these vectors:

i.e s1<-vnk[1]%*%vro[1] +p^(length(vp[1]+1)) 
    s2<-vnk[1:2]%*%vro[1:2]+p^(length(vp[1:2]+1))
    s3<-vnk[1:3]%*%vro[1:3]+p^(length(vp[1:3]+1))
    ...............................
    ...............................
    s200<-vnk[1:200]%*%vro[1:200]+p^(length(vp[1:200]+1))

    s<-[s1 s2 ......s200]

In the code I created I can calculate only the 200th element

vnk<-t(nk^(200:0))
vro<-ro^(0:200)

s<-nz*e*(vnk%*%vp)+p^(length(vp))

if lapply wouldn't need functions but vector arguments it would do the job
perfectly but I don't know the respective command for vectors. If you know
please tell me.

Any help would be highly appreciated

Thanks a lot

Dimitris



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On Mar 14, 2010, at 8:11 AM, Dimitris Kapetanakis wrote:
>
> Dear all,
>
> I would like to create a number of vectors which contain the the  
> first n
> elements of an existing vector.
> For example I have the vectors vnk (200x1) and vro(200x1) and I want  
> to
> create 200 vectors that contain the 1st till the n_th element of the  
> vectors
> and thus be able to create a vector s with 200 elements which are the
> product of all these vectors:
>
> i.e s1<-vnk[1]%*%vro[1] +p^(length(vp[1]+1))
>    s2<-vnk[1:2]%*%vro[1:2]+p^(length(vp[1:2]+1))
>    s3<-vnk[1:3]%*%vro[1:3]+p^(length(vp[1:3]+1))
>    ...............................
>    ...............................
>    s200<-vnk[1:200]%*%vro[1:200]+p^(length(vp[1:200]+1))
>
>    s<-[s1 s2 ......s200]
>
> In the code I created I can calculate only the 200th element
>
> vnk<-t(nk^(200:0))
> vro<-ro^(0:200)
>
> s<-nz*e*(vnk%*%vp)+p^(length(vp))
Here is a guess, untested because you provided no sample data objects:

s <- sapply(1:200, function (x) { vnk[1:x]%*%vro[1:x] +  
p^(length(vp[1:x]+1)) } )
>
> if lapply wouldn't need functions but vector arguments it would do  
> the job
> perfectly but I don't know the respective command for vectors. If  
> you know
> please tell me.
>
> Any help would be highly appreciated
>
> Thanks a lot
>
> Dimitris
>
>

David Winsemius, MD
West Hartford, CT

Thanks a lot. It is exactly what I was looking for. I found though and
another way (worse) to do it, so I just post in case someone find it useful

sk<-nz*e*(vnk[c(i:0)]%*%vro[c(0:i)])

for(i in 0:200){
sk[i]<-nz*e*(vnk[c(i:0)]%*%vro[c(0:i)])
}

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