# [R] saving estimates from a for loop for later use

Brian Quinif bquinif at gmail.com
Sat Apr 8 06:17:07 CEST 2006

```Hi Andy,

I apologize for the flat structure of my code.  I do not know much
well, but could you clarify a couple of things?

In the line

x <- array('', c(4, 1, 6, 2, 3))

where do the numbers 4, 1, 6, 2, 3 come from.  Here are my guesses:
4 = number of rows in orignal matrix Estimates
1 = ?
6 comes from m (m in 1:6)
2 comes from j (j in 1:2)
3 comes from i (i in 1:3)

BQ

2006/4/7, Liaw, Andy <andy_liaw at merck.com>:
> If all the looping variables are of the form 1:k for some k (i.e., they can
> be use as indices in arrays), you can do something like:
>
> x <- array('', c(4, 1, 6, 2, 3))
> for (m in 1:6) {
>    for (i in 1:2) {
>        for (j in 1:3) {
>            compute `Estimates'
>            x[, , m, i, j] <- Estimates
>        }
>    }
> }
>
> You still need to tack on the rownames and colnames to x.
>
> Andy
>
> From: Brian Quinif
> >
> > Thanks for the suggestion, but I do not know how to get it to
> > work for the actual matrix I want to create.  This is not
> > reproducible, but here is the form of the matrix I want:
> >
> > #above I compute satt.yr.hrs and satt.full.load using Match()
> >
> > Estimates <- matrix(c(satt.yr.hrs\$est,
> >
> > In my real program, I have 3 loops with i in 1:3, j in 1:3
> > and m in 1:6.  I want to be able to combine the various
> > versions of Estimates in many combinations to make tables.
> >
> > BQ
> >
> > 2006/4/7, Liaw, Andy <andy_liaw at merck.com>:
> > > If the matrices you're storing inside the loop are all the same
> > > dimension (as in your example), it's probably better to
> > store them in
> > > an array; e.g.:
> > >
> > > i1 <- 2:3
> > > i2 <- 11:12
> > > x <- array(0, c(4, 1, length(i1), length(i2)))
> > >
> > > for (i in seq(along=i1)) {
> > >    for (j in seq(along=i2)) {
> > >        x[, , i, j] <- matrix(c(i1[i], i2[j], i1[i] + i2[j],
> > > i1[i]*i2[j]),
> > > nrow=4)
> > >    }
> > > }
> > > dimnames(x) <- list(NULL, NULL, i1, i2)
> > > x[, , "2", "11", drop=FALSE]
> > > x[, , "3", "11", drop=FALSE]
> > >
> > > (Notice you need the drop=FALSE to keep it a matrix,
> > because it only
> > > has one
> > > column.)
> > >
> > > Andy
> > >
> > > From: Brian Quinif
> > > >
> > > > I kind of understand this recommendation, but I can't
> > figure out how
> > > > to work with x once I have created it.  Here is some fully
> > > > reproducible code.  It creates a 4x1 matrices within the loops.
> > > > Once done with the looping, I want to cbind these
> > matrices together.
> > > > I know it's a simple question, but I can't figure it out.
> > > >
> > > > x <- list()
> > > > for (i in 2:3)
> > > > for (j in 11:12) {
> > > > estimates <- matrix(c(i,j,i+j,i*j),nrow=4)
> > > > x[[as.character(i)]][[as.character(j)]]  <- estimates }
> > > >
> > > >
> > > > So, once I've done this, how can I reference, say, the
> > "estimates"
> > > > matrix created when i=2 and j=12?
> > > >
> > > > Thanks,
> > > >
> > > > BQ
> > > >
> > > > 2006/4/7, jim holtman <jholtman at gmail.com>:
> > > > >
> > > > > use a 'list';
> > > > >
> > > > > x <- list()
> > > > > for (i in 1:3)
> > > > >   for (j in 0:2) {
> > > > >      .....your calculations.....
> > > > >      x[[as.character(i)]][[as.character(j)]] <- yourResults }
> > > > >
> > > > >
> > > > >
> > > > > On 4/7/06, Brian Quinif <bquinif at gmail.com> wrote:
> > > > > >
> > > > > Thanks to the help of many on this list, I am now an R user
> > > > and have
> > > > > been able to write some functioning code to do matching
> > estimation.
> > > > >
> > > > > I have two for loops (i in 1:3, and j in 0:2).  Within
> > the loops, I
> > > > > had been creating matrices of relevant estimation
> > > > coefficents in order
> > > > > to make lots of LaTeX tables.
> > > > >
> > > > > Well, now I want to be able to combine the results of many
> > > > different
> > > > > estimations from within the loops into one larger table
> > outside the
> > > > > loops.
> > > > >
> > > > > How can I save the estimation results from each iteration of the
> > > > > estimation within a loop for later use outside the loop?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > BQ
> > > > >
> > > > > ______________________________________________
> > > > > R-help at stat.math.ethz.ch mailing list
> > > > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > > > http://www.R-project.org/posting-guide.html
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Jim Holtman
> > > > > Cincinnati, OH
> > > > > +1 513 646 9390 (Cell)
> > > > > +1 513 247 0281 (Home)
> > > > >
> > > > > What the problem you are trying to solve?
> > > >
> > > > ______________________________________________
> > > > R-help at stat.math.ethz.ch mailing list
> > > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > > http://www.R-project.org/posting-guide.html
> > > >
> > > >
> > >
> > >
> > >
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