numpy reshape函数使用

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numpy reshape 函数的基本使用

import numpy as np
mat1 = np.array([
                 [[1,2,3],
                  [4,5,6],
                  [7,8,9],
                  [10,11,12]],
                 [[2,4,6],
                  [8,10,12],
                  [14,16,18],
                  [20,22,24]]
                  ])

mat2 = mat1.reshape(-1) # 转换成一个一维行向量
mat3 = mat1.reshape(-1,1,4,3)# 保持第一维不变，在第一维后增加一位，其他维不变

print('mat1:',mat1.shape)
print(mat1)
print('mat2:',mat2.shape)
print(mat2)
print('mat3:',mat3.shape)
print(mat3)

输出：

mat1: (2, 4, 3)
[[[ 1  2  3]
  [ 4  5  6]
  [ 7  8  9]
  [10 11 12]]

 [[ 2  4  6]
  [ 8 10 12]
  [14 16 18]
  [20 22 24]]]
mat2: (24,)
[ 1  2  3  4  5  6  7  8  9 10 11 12  2  4  6  8 10 12 14 16 18 20 22 24]
mat3: (2, 1, 4, 3)
[[[[ 1  2  3]
   [ 4  5  6]
   [ 7  8  9]
   [10 11 12]]]

 [[[ 2  4  6]
   [ 8 10 12]
   [14 16 18]
   [20 22 24]]]]