Question

python numpy 求矩阵有多少列

Answer 1

想知道矩阵A的行数和列数用np.size()函数
np.size(A,0)为矩阵A的行数
np.size(A,1)为矩阵A的列数
（x,y）=np.shape(A)分别求矩阵的行和列

Answer 2

import numpy as np
m=np.zeros([2,3,4])
print(m) -->
[[[0. 0. 0. 0.]
[0. 0. 0. 0.]
[0. 0. 0. 0.]]
[[0. 0. 0. 0.]
[0. 0. 0. 0.]
[0. 0. 0. 0.]]]
print(m.shape[0]) --> 2
print(m.shape[1]) --> 3
print(m.shape[2]) --> 4

Answer 3

import numpy as np
m=np.zeros([2,3])
print(m)
print(len(m[0]))