ndarray 与 scipy.sparse.csr.csr_matrix 的互转

ndarry 转 csr_matrix

>>> import numpy as np
>>> import scipy.sparse>>> my_matrix = scipy.sparse.csr_matrix((2,2))
>>> my_array = my_matrix.A
>>> type(my_array)
numpy.ndarray

csr_matrix 转 ndarray

>>> import numpy as np
>>> from scipy import sparse
>>> A = np.array([[1,2,0],[0,0,3],[1,0,4]])>>> A
array([[1, 2, 0],[0, 0, 3],[1, 0, 4]])>>> sA = sparse.csr_matrix(A)   # Here's the initialization of the sparse matrix.>>> sA
<3x3 sparse matrix of type '<type 'numpy.int32'>'with 5 stored elements in Compressed Sparse Row format>>>> print sA(0, 0)        1(0, 1)        2(1, 2)        3(2, 0)        1(2, 2)        4