Feature Request: "matrix[1:10,1:10, block=F] <- 1:10"
"Warnes, Gregory R" wrote:
Hi Guys, I've again been surprised when something like
m <- matrix("", nrow=3,ncol=3)
index_i <- c(2,1,3)
index_j <- c(1,3,2)
vals <- c("a","b","c")
m[ index_i, index_j ] <- vals
m
gives block-wise application of the assignment:
[,1] [,2] [,3]
[1,] "b" "b" "b"
[2,] "a" "a" "a"
[3,] "c" "c" "c"
Yes, you need to provide the indices as matrix, like: m[cbind(index_i,index_j)] (BTW: Hou do you manage to get index_i <- c(...) properly working? My R version still treats _ as a replacement for <-)
when what I wanted was by-element assignment:
[,1] [,2] [,3]
[1,] "" "" "b"
[2,] "a" "" ""
[3,] "" "c" ""
I always end up writing the code:
for( p in length(index_i) ) m[ index_i[p], index_j[p] ] <- vals[p]
to do what I want. So, I'm thinking about creating a patch to the R source to add an optional parameter, say "block", to the "[<-" call for matrixes and data frames. When "block=T" (the default) the old behaviour is preserved. When "block=F" the behavior I want occures so that
m[ index_i, index_j, block=F ] <- vals
would do what I want. Comments? Cheers? Jeers? Silence? -Greg LEGAL NOTICE Unless expressly stated otherwise, this message is confidential and may be privileged. It is intended for the addressee(s) only. Access to this E-mail by anyone else is unauthorized. If you are not an addressee, any disclosure or copying of the contents of this E-mail or any action taken (or not taken) in reliance on it is unauthorized and may be unlawful. If you are not an addressee, please inform the sender immediately. -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Mag. David Meyer Wiedner Hauptstrasse 8-10
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