Python: how do you store a sparse matrix using python?

Question

I have got an output using sparse matrix in python, i need to store this sparse matrix in my hard disk, how can i do it? if i should create a database then how should i do?? thi

Answer 1

For me, using the -1 option in cPickle.dump function caused the pickled file to not be loadable afterwards.

The object I dumped through cPickle was an instance of scipy.sparse.dok_matrix.

Using only two arguments did the trick for me; documentation about pickle.dump() states the default value of the protocol parameter is 0.

Working on Windows 7, Python 2.7.2 (64 bits), and cPickle v 1.71.

Example:

>>> import cPickle
>>> print cPickle.__version__
1.71
>>> from scipy import sparse
>>> H = sparse.dok_matrix((135, 654), dtype='int32')
>>> H[33, 44] = 8
>>> H[123, 321] = -99
>>> print str(H)
  (123, 321)    -99
  (33, 44)  8
>>> fname = 'dok_matrix.pkl'
>>> f = open(fname, mode="wb")
>>> cPickle.dump(H, f)
>>> f.close()
>>> f = open(fname, mode="rb")
>>> M = cPickle.load(f)
>>> f.close()
>>> print str(M)
  (123, 321)    -99
  (33, 44)  8
>>> M == H
True
>>>