# [R] loop

Ernesto Jardim ernesto at ipimar.pt
Mon Apr 21 12:49:26 CEST 2003

```Olá

Podes criar a lista antes do loop (aliás é aconselhável que o faças para
poupar tempo de computação) e "apontas" os resultados do loop para os
elementos da lista.

lst <- list()
vec <- seq(0,1,0.1)
length(lst)<-length(vec)
for(i in 1:length(vec)){

...

lst[[i]] <- ...

}

Espero que ajude

EJ

PS: The answer is in portuguese.

On Mon, 2003-04-21 at 11:03, Luis Silva wrote:
> I tried the tips from Sundar but I  still have problems. I want
> both values and vectors, and the latter will be used to project
> my original data. The problem is that with those command lines
> I can't get them as a matrix and when I try as.matrix it
> doesn't work. With only vectors
>
> > b<-sapply(my.list, function(x) eigen(x)\$vectors)
> > attributes(b)
> \$dim
> [1] 65536    11
>
> \$dimnames
> \$dimnames[[1]]
> NULL
>
> \$dimnames[[2]]
>
> [1] "0"   "0.1" "0.2" "0.3" "0.4" "0.5" "0.6" "0.7" "0.8" "0.9"
> "1"
>
>
> > b[1]
> [1] 0.02533057+0i
>
> thanks
> luis
>
> }
> }
> } Luis Silva wrote:
> } > Dear helpers
> } >
> } > I have this problem. I want to make a linear
> } combination a*A+(1-
> } > a)*B where A and B are matrices. I want that a be
> } incremented
> } > from 0 to 1 by 0.1 so I made a loop with for. The
> } problem is
> } > that I want to keep the result in an object or list
> } or
> } > something like that and then apply eigen
> } decomposition to all
> } > of the resulting matrices
> } >
> } > sapply(my.list,eigen)
> } >
> } > the problem is that I don't know how to build that
> } list in the
> } > loop. I tried several things but it doesn't work
> } (in Matlab i
> } > can do it)
> } >
> }
> } a <- seq(0, 1, 0.1)
> } my.list <- lapply(a, function(a, A, B) a*A + (a-1)*B,
> } A=A, B=B)
> } names(my.list) <- as.character(a)
> } sapply(my.list, function(x) eigen(x)\$value)
> }
> } Regards,
> } Sundar
> }
> }
>
> --
>
>
>
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```