Here is a slight simplification:
nr <- nrow(m1); nc <- ncol(m1)
lapply(1:nr, function(i) cbind(v1, v2)[cbind(1:nc, (m1+2*m2)[i,])])
On Tue, Jul 28, 2009 at 1:36 PM, Gabor
Grothendieck<ggrothendi...@gmail.com> wrote:
> Try this:
>
>> lapply(1:3, function(i) cbind(v1, v2)[cbind(col(m1)[i,], (m1+2*m2)[i,])])
> [[1]]
> [1] "A" "b" "D" "f"
>
> [[2]]
> [1] "C" "E"
>
> [[3]]
> [1] "D" "e"
>
>
> On Tue, Jul 28, 2009 at 12:48 PM, Jean V Adams<jvad...@usgs.gov> wrote:
>> I've been scratching my head over this one for too long. I'm hoping
>> someone out there can solve this riddle.
>>
>> I have two vectors of characters, v1 and v2, both of length L, and two
>> matrices of logicals, m1 and m2, both of dimension N*L. The first matrix
>> of logicals corresponds to the first vector of characters, and the second
>> to the second.
>>
>> The matrices are telling me which of the elements of v1 and v2 are
>> selected, and for each of the L elements either a value from v1 is
>> selected, a value from v2 is selected, or neither is selected (but both
>> are never selected). So, the two matrices never have a TRUE in the same
>> place, i.e., m1 + m2 yields a matrix of 0s and 1s (no 2s).
>>
>> What I would like to end up with is a list of length N, that has the
>> selected elements of v1 and v2 meshed together in their original order.
>>
>> Here's an example (using much smaller N and L than in my real data):
>>
>> v1 <- LETTERS[1:6]
>> v2 <- letters[1:6]
>>
>> m1 <- matrix(c(T, F, F, T, F, F, F, F, T, F, T, F, F, F, F, T, F, F),
>> byrow=T, ncol=6)
>> m2 <- matrix(c(F, T, F, F, F, T, F, F, F, F, F, F, F, F, F, F, T, F),
>> byrow=T, ncol=6)
>>
>> v1
>> v2
>> m1
>> m2
>> m1+m2
>>
>> Given these two vectors and two matrices, I want to end up with this list:
>>
>> result <- list(c("A", "b", "D", "f"), c("C", "E"), c("D", "e"))
>> result
>>
>> I'm using R for Windows version 2.9.0.
>>
>> Thanks for your help.
>>
>> Jean
>>
>>
>> `·.,, ><(((º> `·.,, ><(((º> `·.,, ><(((º>
>>
>> Jean V. Adams
>> Statistician
>> U.S. Geological Survey
>> Great Lakes Science Center
>> 223 East Steinfest Road
>> Antigo, WI 54409 USA
>> phone: 715-623-4190, ext. 3125
>> FAX: 715-623-6773
>> GLSC web site: http://www.glsc.usgs.gov
>> e-mail: jvad...@usgs.gov
>> [[alternative HTML version deleted]]
>>
>>
>> ______________________________________________
>> R-help@r-project.org 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@r-project.org 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.
