Creating a 3D array from 2D array

x = 121 x 27
y = 121 x 27
z = 121 x 27

I need to create a 3D array from these 2D arrays as following:

xyz= 121 x 3 x 27

where rows equal 121 ; columns equal 3 ( x(1,1) y(1,1) z(1,1) , x(2,1) y(2,1) z(2,1), ... x(n,1) y(n,1) z(n,1), x(1,2) y(1,2) z(1,2), ... x(1,n) y(1,n) z(1,n) ) ; slices equal 27.

Answer 1

[Dave B]

You can use the cat command for this:

x=rand(121,27);
y=rand(121,27);
z=rand(121,27);

xyz=cat(3,x,y,z);
size(xyz)

ans = 1×3

121 27 3

Or you can initialize a 3-D matrix and stick your 2-D matrices in:

xyz2=nan([size(x) 3]);
xyz2(:,:,1)=x;
xyz2(:,:,2)=y;
xyz2(:,:,3)=z;

isequal(xyz,xyz2) % just to confirm that both methods do the same thing

ans = logical
   1

[Adam]

Also to get the 121x3x27 final result you can just do

permute( xyz, [1 3 2] )

at the end.

[Dave B]

Sorry I missed the bit about the order, if you don't want to do the permute bit you can alter the second method to:

x=rand(121,27);
y=rand(121,27);
z=rand(121,27);

xyz = nan([size(x,1) 3 size(x,2)]); 
xyz(:,1,:)=x;
xyz(:,2,:)=y;
xyz(:,3,:)=z;

size(xyz)

ans = 1×3

121 3 27

[sermet OGUTCU]

Dear @Dave B,

Thanks a lot for the solution.