Column-by-column division

Hello,

I forgot about sweep:


sweep(x, 2, s, '/')
sweep(x, 2, 1:4, '/')


Hope this helps,

Rui Barradas

?s 11:12 de 03/03/21, Rui Barradas escreveu:

Hello,

Maybe define an infix operator?


`%!%` <- function(x, y) {
?? stopifnot(ncol(x) == length(y))
?? t(t(x)/y)
}

x <- matrix(1:20, ncol = 2)
s <- 1:2

x %!% s
x %!% 1:4


Hope this helps,

Rui Barradas

?s 11:00 de 03/03/21, Steven Yen escreveu:

I have a 10 x 2 matrix x. Like to divide the first column by s[1] 
and second column by s[2]. The following lines work but are clumsy. 
Any idea? Thanks.

?> x
?????? [,1] [,2]
??[1,]??? 1?? 11
??[2,]??? 2?? 12
??[3,]??? 3?? 13
??[4,]??? 4?? 14
??[5,]??? 5?? 15
??[6,]??? 6?? 16
??[7,]??? 7?? 17
??[8,]??? 8?? 18
??[9,]??? 9?? 19
[10,]?? 10?? 20
?> s
[1] 1 2
?> t(t(x)/s)
?????? [,1] [,2]
??[1,]??? 1? 5.5
??[2,]??? 2? 6.0
??[3,]??? 3? 6.5
??[4,]??? 4? 7.0
??[5,]??? 5? 7.5
??[6,]??? 6? 8.0
??[7,]??? 7? 8.5
??[8,]??? 8? 9.0
??[9,]??? 9? 9.5
[10,]?? 10 10.0