Somewhat out of my depth here (I have only 2 arms, but am
swimming in waters which require 3): My interpretation is
that a and M are basically vectors, with dimension attributes,
accessed down the columns.
The array 'a' consists of 30 elements 1:30 in that order,
accessed by each of 3 rows for eac
thank you Simon.
I find a[M] working to be unexpected, but consistent with (a close
reading of) Extract.Rd
Can we reproduce a[,M]?
[I would expect this to extract a[,j,k] where M[j,k] is TRUE]
try this:
> a <- array(1:30,c(3,5,2))
> M <- matrix(1:10,5,2) %% 3==1
> a[M]
[1] 1 4 7 10 11 14
a[M] gives the same as your `cobbled together' code.
On Wed, Sep 28, 2011 at 6:35 AM, robin hankin wrote:
> hello everyone.
>
> Look at the following R idiom:
>
> a <- array(1:30,c(3,5,2))
> M <- (matrix(1:15,c(3,5)) %% 4) < 2
> a[M,] <- 0
>
> Now, I think that "a[M,]" has an unambiguous meani
hello everyone.
Look at the following R idiom:
a <- array(1:30,c(3,5,2))
M <- (matrix(1:15,c(3,5)) %% 4) < 2
a[M,] <- 0
Now, I think that "a[M,]" has an unambiguous meaning (to a human).
However, the last line doesn't work as desired, but I expected it
to...and it recently took me an indecent
