A matrix is a two-dimensional data structure with a fixed number of columns and rows. Each element of a matrix can be referred to by its column and the row.

In Python, a matrix can be created by using the numpy array, as shown in the following code:

>>> myMatrix = np.array([[11, 12, 13], [21, 22, 23], [31, 32, 33]]) 
>>> print(myMatrix) 
[[11 12 13]  
[21 22 23]  
[31 32 33]]
>>> print(type(myMatrix))
<class 'numpy.ndarray'>

Note that the preceding code will create a matrix that has three rows and three columns.