将列添加到稀疏矩阵

Question

当我执行以下代码时,我得到一个备用矩阵:

import numpy as np
from scipy.sparse import csr_matrix

row = np.array([0, 0, 1, 2, 2, 2])
col = np.array([0, 2, 2, 0, 1, 2])
data = np.array([1, 2, 3, 4, 5, 6])
sp = csr_matrix((data, (row, col)), shape=(3, 3))
print(sp)

  (0, 0)        1
  (0, 2)        2
  (1, 2)        3
  (2, 0)        4
  (2, 1)        5
  (2, 2)        6

我想在这个稀疏矩阵中添加另一列,因此输出为:

  (0, 0)        1
  (0, 2)        2
  (0, 3)        7
  (1, 2)        3
  (1, 3)        7
  (2, 0)        4
  (2, 1)        5
  (2, 2)        6
  (2, 3)        6

基本上我想添加另一个值为7,7,7的列.

Answer 1

将sparse.hstack用于@Paul Panzer's链接是最简单的.

In [760]: sparse.hstack((sp,np.array([7,7,7])[:,None])).A
Out[760]: 
array([[1, 0, 2, 7],
       [0, 0, 3, 7],
       [4, 5, 6, 7]], dtype=int32)

sparse.hstack并不复杂; 它只是打电话bmat([blocks]).

sparse.bmat获取coo所有块的属性,将它们与适当的自身连接起来,然后构建一个新的块coo_matrix.

在这种情况下,它加入

In [771]: print(sp)
  (0, 0)    1
  (0, 2)    2
  (1, 2)    3
  (2, 0)    4
  (2, 1)    5
  (2, 2)    6
In [772]: print(sparse.coo_matrix(np.array([7,7,7])[:,None]))
  (0, 0)    7
  (1, 0)    7
  (2, 0)    7

同时将最后一列的列号更改为3.

In [761]: print(sparse.hstack((sp,np.array([7,7,7])[:,None])))
  (0, 0)    1
  (0, 2)    2
  (1, 2)    3
  (2, 0)    4
  (2, 1)    5
  (2, 2)    6
  (0, 3)    7
  (1, 3)    7
  (2, 3)    7