DynV Montrealer
2024-May-03 12:47 UTC
[R] Get a copy of a matrix only for TRUE entries of a matching size boolean matrix?
Is there a way to get a copy of a matrix only for TRUE entries of a matching size boolean matrix? For *example*:> mat_letters <- matrix(data=c('A', 'B', 'C', 'D'), ncol=2, byrow=TRUE) > mat_letters[,1] [,2] [1,] "A" "B" [2,] "C" "D"> mat_bools <- matrix(data=c(FALSE, TRUE, TRUE, FALSE), ncol=2, byrow=TRUE) > mat_bools[,1] [,2] [1,] FALSE TRUE [2,] TRUE FALSE *Reminder:* The following is only an example ; the solution might look very different. some_command(mat_letters, mat_bools, false=empty) [,1] [,2] [1,] "" "B" [2,] "C" "" some_command(mat_letters, mat_bools, false=na) [,1] [,2] [1,] NA "B" [2,] "C" NA Thank you kindly [[alternative HTML version deleted]]
Ben Bolker
2024-May-03 14:24 UTC
[R] Get a copy of a matrix only for TRUE entries of a matching size boolean matrix?
In two steps:
result <- matrix(NA_character_,
nrow=nrow(mat_letters), ncol =ncol(mat_letters))
result[mat_bools] <- mat_letters[mat_bools]
On 2024-05-03 8:47 a.m., DynV Montrealer wrote:> Is there a way to get a copy of a matrix only for TRUE entries of a
> matching size boolean matrix? For *example*:
>> mat_letters <- matrix(data=c('A', 'B', 'C',
'D'), ncol=2, byrow=TRUE)
>> mat_letters
> [,1] [,2]
> [1,] "A" "B"
> [2,] "C" "D"
>> mat_bools <- matrix(data=c(FALSE, TRUE, TRUE, FALSE), ncol=2,
byrow=TRUE)
>> mat_bools
> [,1] [,2]
> [1,] FALSE TRUE
> [2,] TRUE FALSE
> *Reminder:* The following is only an example ; the solution might look very
> different.
> some_command(mat_letters, mat_bools, false=empty)
> [,1] [,2]
> [1,] "" "B"
> [2,] "C" ""
> some_command(mat_letters, mat_bools, false=na)
> [,1] [,2]
> [1,] NA "B"
> [2,] "C" NA
>
> Thank you kindly
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
Marc Girondot
2024-May-03 14:28 UTC
[R] Get a copy of a matrix only for TRUE entries of a matching size boolean matrix?
Is it what you want ?
mat_letters <- matrix(data=c('A', 'B', 'C',
'D'), ncol=2, byrow=TRUE)
mat_bools <- matrix(data=c(FALSE, TRUE, TRUE, FALSE), ncol=2, byrow=TRUE)
ifelse(mat_bools, mat_letters, "")
ifelse(mat_bools, mat_letters, NA)
> ifelse(mat_bools, mat_letters, "")
???? [,1] [,2]
[1,] ""?? "B"
[2,] "C"? ""
> ifelse(mat_bools, mat_letters, NA)
???? [,1] [,2]
[1,] NA?? "B"
[2,] "C"? NA
Marc
Le 03/05/2024 ? 14:47, DynV Montrealer a ?crit?:> Is there a way to get a copy of a matrix only for TRUE entries of a
> matching size boolean matrix? For*example*:
>> mat_letters <- matrix(data=c('A', 'B', 'C',
'D'), ncol=2, byrow=TRUE)
>> mat_letters
> [,1] [,2]
> [1,] "A" "B"
> [2,] "C" "D"
>> mat_bools <- matrix(data=c(FALSE, TRUE, TRUE, FALSE), ncol=2,
byrow=TRUE)
>> mat_bools
> [,1] [,2]
> [1,] FALSE TRUE
> [2,] TRUE FALSE
> *Reminder:* The following is only an example ; the solution might look very
> different.
> some_command(mat_letters, mat_bools, false=empty)
> [,1] [,2]
> [1,] "" "B"
> [2,] "C" ""
> some_command(mat_letters, mat_bools, false=na)
> [,1] [,2]
> [1,] NA "B"
> [2,] "C" NA
[[alternative HTML version deleted]]