Rearranging array based on number of steps.

Hi everybody,

Let's say I have a vector such as:

A = (1:24)

And I'd like to separate this array into a 2x12 matrix where the first row will show the first 3 positions skipping the next three and so on... The second row will do the same thing but starting from the fourth position. This is the expexted output:

Output = [1 2 3 7 8 9 13 14 15 19 20 21; 4 5 6 10 11 12 16 17 18 22 23 24]

I could do this manually, but some times I'd like it to take 2 or 4 steps instead of 3, as it is in the example above.

Any ideas of how to to achieve this?

Thank you in advanced,

Santos

Answer 1

[Stephen23]

https://www.mathworks.com/help/matlab/ref/reshape.html

https://www.mathworks.com/help/matlab/ref/permute.html

A = 1:24;
N = 3; % number of "steps"
R = 2; % number of rows
M = reshape(permute(reshape(A,N,R,[]),[2,1,3]),R,[])

M = 2×12

1 2 3 7 8 9 13 14 15 19 20 21 4 5 6 10 11 12 16 17 18 22 23 24

[1,2,3,7,8,9,13,14,15,19,20,21;4,5,6,10,11,12,16,17,18,22,23,24]

ans = 2×12

1 2 3 7 8 9 13 14 15 19 20 21 4 5 6 10 11 12 16 17 18 22 23 24

[Santos García Rosado]

Thank you Steven! Neve thought of nesting permute with reshape that way. Thanks!