How to create a multidimensional matrix in Python-CodePudding

I am a beginner in Python. I want to create the matrix below, how should I create it?

[
    [0,1], [0,2], [0,3],
    [1,1], [1,2], [1,3],
    [2,1], [2,2], [2,3],
    [3,1], [3,2], [3,3]
]

I looked up numpy, maybe I'm not looking in the right way, I didn't find any good way.

CodePudding user response：

This is almost what numpy.ndindex is doing, except you want one of the values to start with 1. You can fix it by converting to array and adding 1:

np.array(list(np.ndindex(4,3))) [0,1]

Output:

array([[0, 1],
       [0, 2],
       [0, 3],
       [1, 1],
       [1, 2],
       [1, 3],
       [2, 1],
       [2, 2],
       [2, 3],
       [3, 1],
       [3, 2],
       [3, 3]])

CodePudding user response：

A rather simple list comprehension will generate this data structure. Numpy not required.

[[x, y] for x in range(4) for y in range(1, 4)]

Result:

[[0, 1], [0, 2], [0, 3], 
 [1, 1], [1, 2], [1, 3], 
 [2, 1], [2, 2], [2, 3], 
 [3, 1], [3, 2], [3, 3]]