Message-ID: <baa2781d-0371-401d-b8a5-62b5f693eec5@gmail.com>
Date: 2020-08-11T01:23:01Z
From: Ben Bolker
Subject: M[cbind()] <- assignment with Matrix object loses attributes
? Does this constitute a bug, or is there something I'm missing?
assigning sub-elements of a sparse Matrix via M[X]<-..., where X is a
2-column matrix, appears to drop user-assigned attributes. I dug around
in the R code for Matrix trying to find the relevant machinery but my
brain started to hurt too badly ...
?? Will submit this as a bug if it seems warranted.
library(Matrix)
m1 <- matrix(1:9,3,3)
m1 <- Matrix(m1)
attr(m1,"junk") <- 12
stopifnot(isTRUE(attr(m1,"junk")==12))? ## OK
m1[cbind(1:2,2:3)] <- 1
stopifnot(isTRUE(attr(m1,"junk")==12)) ## not OK
attr(m1,"junk") ## NULL
## note I have to use the ugly stopifnot(isTRUE(...)) because a missing
attribute returns NULL, an assignment to NULL returns NULL, and
stopifnot(NULL) doesn't stop ...
?? cheers
???? Ben Bolker