save_npz — SciPy v1.15.3 Manual (original) (raw)

scipy.sparse.

scipy.sparse.save_npz(file, matrix, compressed=True)[source]#

Save a sparse matrix or array to a file using .npz format.

Parameters:

filestr or file-like object

Either the file name (string) or an open file (file-like object) where the data will be saved. If file is a string, the .npzextension will be appended to the file name if it is not already there.

matrix: spmatrix or sparray

The sparse matrix or array to save. Supported formats: csc, csr, bsr, dia or coo.

compressedbool, optional

Allow compressing the file. Default: True

Examples

Store sparse matrix to disk, and load it again:

import numpy as np import scipy as sp sparse_matrix = sp.sparse.csc_matrix([[0, 0, 3], [4, 0, 0]]) sparse_matrix <Compressed Sparse Column sparse matrix of dtype 'int64' with 2 stored elements and shape (2, 3)> sparse_matrix.toarray() array([[0, 0, 3], [4, 0, 0]], dtype=int64)

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

sparse_matrix <Compressed Sparse Column sparse matrix of dtype 'int64' with 2 stored elements and shape (2, 3)> sparse_matrix.toarray() array([[0, 0, 3], [4, 0, 0]], dtype=int64)