[R] [External] struggling with apply

[Richard M. Heiberger]

sapply(1:4, FUN=function(i, x, UB=c(2.5, 5.5, 8.5, 10.5)) {result <-
x[,i]; result[result > UB[i]] <- UB[i]; result}, x=somematrix)

On Wed, May 27, 2020 at 1:46 PM Michael Ashton
<m.ashton using enduringinvestments.com> wrote:
>
> Hi -
>
> I have a matrix of n rows and 4 columns.
>
> I want to cap the value in each column by a different upper bound. So, suppose my matrix is
>
> somematrix <- matrix(c(1,4,3,6,3,9,12,8,5,7,11,11),nrow=3,ncol=4)
> > somematrix
>      [,1] [,2] [,3] [,4]
> [1,]    1    6   12    7
> [2,]    4    3    8   11
> [3,]    3    9    5   11
>
> Now I want to have the maximum value in each column described by
> UB=c(2.5, 5.5, 8.5, 10.5)
>
> So that the right answer will look like:
>      [,1]      [,2]    [,3]   [,4]
> [1,]    1      5.5     8.5    7
> [2,]    2.5    3        8     10.5
> [3,]    2.5   5.5      5    10.5
>
> I've tried a few things, like:
> newmatrix <- apply(somematrix,c(1,2),function(x) min(UB,x))
>
> but I can't figure out to apply the relevant element of the UB list to the right element of the matrix. When I run the above, for example, it takes min(UB,x) over all UB, so I get:
>
> newmatrix
>      [,1] [,2] [,3] [,4]
> [1,]  1.0  2.5  2.5  2.5
> [2,]  2.5  2.5  2.5  2.5
> [3,]  2.5  2.5  2.5  2.5
>
> I'm sure there's a simple and elegant solution but I don't know what it is!
>
> Thanks in advance,
>
> Mike
>
> Michael Ashton, CFA
> Managing Principal
>
> Enduring Investments LLC
> W: 973.457.4602
> C: 551.655.8006
> Schedule a Call: https://calendly.com/m-ashton
>
>
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