Multidimensional Arrays
An array having more than two dimensions is called a multidimensional array in MATLAB. Multidimensional arrays in MATLAB are an extension of the normal two-dimensional matrix.
Generally to generate a multidimensional array, we first create a two-dimensional array and extend it.
For example, let's create a two-dimensional array a.
a = [7 9 5; 6 1 9; 4 3 2]
MATLAB will execute the above statement and return the following result −
a =
7 9 5
6 1 9
4 3 2
The array a is a 3-by-3 array; we can add a third dimension to a, by providing the values like −
a(:, :, 2)= [ 1 2 3; 4 5 6; 7 8 9]
MATLAB will execute the above statement and return the following result −
a(:,:,1) =
7 9 5
6 1 9
4 3 2
a(:,:,2) =
1 2 3
4 5 6
7 8 9
We can also create multidimensional arrays using the ones(), zeros() or the rand() functions.
For example,
b = rand(4,3,2)
MATLAB will execute the above statement and return the following result −
b(:,:,1) =
0.0344 0.7952 0.6463
0.4387 0.1869 0.7094
0.3816 0.4898 0.7547
0.7655 0.4456 0.2760
b(:,:,2) =
0.6797 0.4984 0.2238
0.6551 0.9597 0.7513
0.1626 0.3404 0.2551
0.1190 0.5853 0.5060
We can also use the cat() function to build multidimensional arrays. It concatenates a list of arrays along a specified dimension −
Syntax for the cat() function is −
B = cat(dim, A1, A2...)
Where,
- B is the new array created
- A1, A2, ... are the arrays to be concatenated
- dim is the dimension along which to concatenate the arrays
Example
Create a script file and type the following code into it −
a = [9 8 7; 6 5 4; 3 2 1]; b = [1 2 3; 4 5 6; 7 8 9]; c = cat(3, a, b, [ 2 3 1; 4 7 8; 3 9 0])
When you run the file, it displays −
c(:,:,1) =
9 8 7
6 5 4
3 2 1
c(:,:,2) =
1 2 3
4 5 6
7 8 9
c(:,:,3) =
2 3 1
4 7 8
3 9 0