math_daddy wrote:
Hello. I've observed some odd behaviour. Most likely, it is already known and
explained somewhere, but I can't find an explanation anywhere, so I would
appreciate being pointed in the right direction.
The issue with the following code is self explanatory:
mat <- matrix(c(c(1,1,1),c(2,2,2)),nrow=3)
mat[,c(1:3%/%2)]
[,1] [,2]
[1,] 1 1
[2,] 1 1
[3,] 1 1
n <- 3%/%2
mat[,c(1:n)]
[1] 1 1 1
What I want to know is, why does it give the first column twice when 3%/%2
is computed within the subset call, and just the first row when it is
computed outside?
Hint:
Look at
c(1:3 %/% 2)
It's an Order of Operations Thing.
See ?Syntax
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