Python | Numpy | np.newaxis有什么作用？[np.newaxis,:][:,np.newaxis][np.newaxis,:,np.newaxis]

Posted 2022-09-22 人工智能博士

理解一下：

np.newaxis是用来增加一个维度，比如原来是1维的，我可以用它变成2维，甚至3维的！

import numpy as np
x=np.array([1,2,3,4,5,6,7,8,9,10])
print(x)
print(x.shape)

[ 1  2  3  4  5  6  7  8  9 10]
(10,)

import numpy as np
x=np.array([1,2,3,4,5,6,7,8,9,10])
y = x[np.newaxis,:]
print(y)
print(y.shape)

[[ 1  2  3  4  5  6  7  8  9 10]]
(1, 10)

import numpy as np
x=np.array([1,2,3,4,5,6,7,8,9,10])
y = x[:,np.newaxis]
print(y)
print(y.shape)

[[ 1]
 [ 2]
 [ 3]
 [ 4]
 [ 5]
 [ 6]
 [ 7]
 [ 8]
 [ 9]
 [10]]
(10, 1)

import numpy as np
x=np.array([1,2,3,4,5,6,7,8,9,10])
y = x[np.newaxis,:,np.newaxis]
print(y)
print(y.shape)

[[[ 1]
  [ 2]
  [ 3]
  [ 4]
  [ 5]
  [ 6]
  [ 7]
  [ 8]
  [ 9]
  [10]]]
(1, 10, 1)