Determine whether arrays of different sizes are matrices.

Create an array of size 1-by-3. Determine whether it is a matrix.

A1 = zeros(1,3);
TF = ismatrix(A1)

TF = logical
   1

Create an empty array of size 0-by-3. Determine whether it is a matrix. A 2-D empty array is a matrix.

A2 = zeros(0,3);
TF = ismatrix(A2)

TF = logical
   1

Create an array of size 1-by-3-by-2. Determine whether it is a matrix. A 3-D array is not a matrix.

A3 = zeros(1,3,2);
TF = ismatrix(A3)

TF = logical
   0

Create a 3-D array and determine whether the array elements are a matrix.

First define a 2-D array of size 2-by-3. Determine whether it is a matrix.

A = [0.1 0.2 0.5; 0.3 0.6 0.4]

A = 2×3

    0.1000    0.2000    0.5000
    0.3000    0.6000    0.4000

TF = ismatrix(A)

TF = logical
   1

To create a 3-D array, add a third dimension to the array A. Assign another 2-by-3 matrix to the third dimension of A with index value 2.

A(:,:,2) = ones(2,3)

A = 
A(:,:,1) =

    0.1000    0.2000    0.5000
    0.3000    0.6000    0.4000


A(:,:,2) =

     1     1     1
     1     1     1

Check whether the 3-D array of size 2-by-3-by-2 is a matrix.

TF = ismatrix(A)

TF = logical
   0

Now determine whether the array elements of A are a matrix. Check whether the second page of the 3-D array is a matrix. The syntax A(:,:,2) uses a colon in the first and second dimensions to access all rows and all columns.

TF = ismatrix(A(:,:,2))

TF = logical
   1

Check whether the second row of the 3-D array is a matrix. The syntax A(2,:,:) uses a colon in the second and third dimensions to include all columns and all pages.

TF = ismatrix(A(2,:,:))

TF = logical
   0

A(:,:,2) is a matrix since it is a multidimensional array of size 2-by-3. However, A(2,:,:) is not a matrix since it is a multidimensional array of size 1-by-3-by-2.

Create an array of characters. Determine whether it is a matrix.

A = 'Hello, World!';
TF = ismatrix(A)

TF = logical
   1

Check the dimension of A using size. A is a matrix of size 1-by-13.

size(A)

ans = 1×2

     1    13

Now create a string scalar by enclosing a piece of text in double quotes.

A = "Hello, World!";

Check whether the scalar A of size 1-by-1 is also a matrix.

TF = ismatrix(A)

TF = logical
   1