loop through numpy array produces typerror output : only integer scalar arrays can be converted to a-CodePudding

Say I have the following array a and subset 2x2 matrices from it:

import numpy as np
np.random.seed(0)

a = np.random.randint(9,size=(3,2,2))

for i in range(a.shape[0]):
    m = a[i]
    print(type(m))
    print(m)

<class 'numpy.ndarray'>
[[5 0]
 [3 3]]
<class 'numpy.ndarray'>
[[7 3]
 [5 2]]
<class 'numpy.ndarray'>
[[4 7]
 [6 8]]

Now if I want to loop through each of the matrices I get an error:

for i in range(a.shape[0]):
    m = a[i]
    for j in range(m):
        print(j)

TypeError: only integer scalar arrays can be converted to a scalar index

Why is that ? Can't really debug this typerror.

CodePudding user response：

You are trying to take the range of the matrix m, which doesn't exist and thus the error. Instead, you should take the range of its shape[0] as you did in the first line for matrix a.

If you want to loop into each position of each matrix, then

import numpy as np
np.random.seed(0)

a = np.random.randint(9,size=(3,2,2))

for i in range(a.shape[0]):
    m = a[i]
    print(type(m))
    print(m)
    
for i in range(a.shape[0]):
    m = a[i]
    print("---")
    for x in range(m.shape[0]):
        for y in range(m.shape[1]):
            print(m[x,y])