[R] Rotate array by 90°

[Karim Mezhoud]

Thanks Jeff and Rui.




On Thu, Feb 5, 2015 at 11:12 PM, Rui Barradas <ruipbarradas at sapo.pt> wrote:

> Hello,
>
> Try the following.
>
>
> rot90 <- function(x, n = 1){
>         r90 <- function(x){
>                 y <- matrix(rep(NA, prod(dim(x))), nrow = nrow(x))
>                 for(i in seq_len(nrow(x))) y[, i] <- rev(x[i, ])
>                 y
>         }
>         for(i in seq_len(n)) x <- r90(x)
>         x
> }
>
> mat <- matrix(letters[1:9], byrow = TRUE, nrow = 3)
>
> rot90(mat)
> rot90(mat, 3)
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 05-02-2015 21:17, Karim Mezhoud escreveu:
>
>> Dear aal,
>>
>> Is there a way to rotate array or a cube of matrices by Y axis?
>>
>>
>> MatLab example:
>>
>> A = cat(3,{'a' 'b' 'c';'d' 'e' 'f';'g' 'h' 'i'},{'j' 'k' 'l';'m' 'n'
>> 'o';'p' 'q' 'r'})
>>
>> A(:,:,1) =
>>
>>      'a'    'b'    'c'
>>      'd'    'e'    'f'
>>      'g'    'h'    'i'
>>
>>
>> A(:,:,2) =
>>
>>      'j'    'k'    'l'
>>      'm'    'n'    'o'
>>      'p'    'q'    'r'
>>
>> Rotate the cell array by 270 degrees.
>>
>> B = rot90(A,3)
>>
>> B(:,:,1) =
>>
>>      'g'    'd'    'a'
>>      'h'    'e'    'b'
>>      'i'    'f'    'c'
>>
>>
>> B(:,:,2) =
>>
>>      'p'    'm'    'j'
>>      'q'    'n'    'k'
>>      'r'    'o'    'l'
>>
>>
>> karim
>>
>>         [[alternative HTML version deleted]]
>>
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>>

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