np.newaxis用法

插入新维度

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import numpy as np a=np.array([1,2,3,4,5]) print ('a:',a) print('a.shape',a.shape) a1=a[:,np.newaxis] print ('a1:\n',a1) print('a1.shape',a1.shape) a2=a[np.newaxis,:] print ('a2:\n',a1) print('a2.shape',a2.shape)

结果

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a: [1 2 3 4 5] a.shape (5,) a1:  [[1]        [2]         [3]         [4]         [5]]       a1.shape (5, 1) a2:  [[1]  [2]  [3]  [4]  [5]] a2.shape (1, 5)