Timeline for answer to Extract Matrix of Values from Matrix using Matrix of Row Numbers by Nadir AMMISAID

9 events

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Apr 10 at 8:38	comment	added	Nadir AMMISAID		@Greg Thanks Greg. Agreed ! dim<- is the idiomatic solution here. At the R level, [ returns a vector, so there's no special extraction form that preserves the shape directly; whether resetting dim happens truly in place depends on copy-on-modify semantics.
Apr 10 at 8:37	history	edited	Nadir AMMISAID	CC BY-SA 4.0	Clarified why dim<- is the idiomatic solution and added note about copy-on-modify semantics
Apr 9 at 18:30	comment	added	Rui Barradas		Another one-liner is `'dim<-'(vals[val_rows, val_col], dim(val_rows))`. (With back quotes.)
Apr 9 at 16:28	comment	added	Greg		Hello Nadir, and welcome! You are right that `byrow = TRUE` is inappropriate, and that helped me realize that my `dim<-`() approach was correct all along. I simply "had my wires crossed" regarding my output. I have updated my post with clearer output and questions.
Apr 9 at 16:17	comment	added	Greg		@G Don't `array()` and `structure()` both pass by value? I'm hoping that something exists which is (1) similar to `dim<-`() and (2) can redimension "in place", without copying the underlying data.
Apr 9 at 16:11	comment	added	G. Grothendieck		You might want to use `array` instead of `structure`.
Apr 9 at 15:43	vote	accept	Greg
Apr 9 at 16:03
S Apr 9 at 15:20	review	First answers
Apr 9 at 15:26
S Apr 9 at 15:20	history	answered	Nadir AMMISAID	CC BY-SA 4.0