`scipy.sparse._matrix_io:load_npz`

Signature

def load_npz(file)

Load a sparse array/matrix from a file using .npz format.

file : str or file-like object: Either the file name (string) or an open file (file-like object) where the data will be loaded.

result : csc_array, csr_array, bsr_array, dia_array or coo_array: A sparse array/matrix containing the loaded data.

Store sparse array/matrix to disk, and load it again:

import numpy as np
import scipy as sp
sparse_array = sp.sparse.csc_array([[0, 0, 3], [4, 0, 0]])

✓

sparse_array
sparse_array.toarray()

✗

array([[0, 0, 3],
       [4, 0, 0]])

sp.sparse.save_npz('/tmp/sparse_array.npz', sparse_array)
sparse_array = sp.sparse.load_npz('/tmp/sparse_array.npz')

✓

sparse_array
sparse_array.toarray()

✗

array([[0, 0, 3],
       [4, 0, 0]])

In this example we force the result to be csr_array from csr_matrix