这个
coo_matrix
类不支持索引。您必须将其转换为其他稀疏格式。
下面是一个例子
库克矩阵
:
In [19]: import numpy as np
In [20]: from scipy.sparse import coo_matrix
In [21]: m = coo_matrix([[0, 0, 0, 1], [2, 0, 0 ,0], [0, 0, 0, 0], [0, 3, 4, 0]])
正在尝试索引
m
失败:
In [22]: m[0,0]
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-22-1f78c188393f> in <module>()
----> 1 m[0,0]
TypeError: 'coo_matrix' object is not subscriptable
In [23]: idx = np.array([2, 3])
In [24]: m[idx]
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-24-a52866a6fec6> in <module>()
----> 1 m[idx]
TypeError: only integer scalar arrays can be converted to a scalar index
如果你改变信仰
米
对于CSR矩阵,可以用
idx
:
In [25]: m.tocsr()[idx]
Out[25]:
<2x4 sparse matrix of type '<class 'numpy.int64'>'
with 2 stored elements in Compressed Sparse Row format>
如果要进行更多的索引,最好将新数组保存在变量中,并根据需要使用它:
In [26]: a = m.tocsr()
In [27]: a[idx]
Out[27]:
<2x4 sparse matrix of type '<class 'numpy.int64'>'
with 2 stored elements in Compressed Sparse Row format>
In [28]: a[0,0]
Out[28]: 0