如何将2d numpy数组制作成3d数组？

Question

我有一个带有形状(x,y)的二维数组,我想将其转换为具有形状(x,y,1)的3d数组.有没有一个很好的Pythonic方法来做到这一点？

Answer 1

除了其他答案,您还可以使用切片numpy.newaxis:

>>> from numpy import zeros, newaxis
>>> a = zeros((6, 8))
>>> a.shape
(6, 8)
>>> b = a[:, :, newaxis]
>>> b.shape
(6, 8, 1)

甚至这个(它将使用任意数量的维度):

>>> b = a[..., newaxis]
>>> b.shape
(6, 8, 1)

Answer 2

numpy.reshape(array, array.shape + (1,))

Answer 3

import numpy as np

# create a 2D array
a = np.array([[1,2,3], [4,5,6], [1,2,3], [4,5,6],[1,2,3], [4,5,6],[1,2,3], [4,5,6]])

print(a.shape) 
# shape of a = (8,3)

b = np.reshape(a, (8, 3, -1)) 
# changing the shape, -1 means any number which is suitable

print(b.shape) 
# size of b = (8,3,1)