06给数组增加一个维度

import numpy as np

arr = np.arange(5)
print(arr)
print(arr.shape)

#method1
print(arr[np.newaxis,:])
print(arr[np.newaxis,:].shape)

print(arr[:,np.newaxis])
print(arr[:,np.newaxis].shape)
print('****************************************')

#method2
print(np.expand_dims(arr,axis=0))
print(np.expand_dims(arr,axis=0).shape)

print(np.expand_dims(arr,axis=1))
print(np.expand_dims(arr,axis=1).shape)
print('****************************************')

#method3
print(np.reshape(arr,(1,5)))
print(np.reshape(arr,(1,-1)))
print(np.reshape(arr,(1,-1)).shape)

print(np.reshape(arr,(-1,1)))
print(np.reshape(arr,(-1,1)).shape)