convert list and list of lists to scipy sparse arrays

Question

Suppose I have a list or a list of lists (each list with the same size). How do I convert to a sparse vector or sparse matrix, respectively?

Answer 1

In [5]: scipy.sparse.csr_matrix([[1, 2], [3, 0]])
Out[5]:
<2x2 sparse matrix of type '<type 'numpy.int64'>'
        with 3 stored elements in Compressed Sparse Row format>

In [6]: scipy.sparse.csr_matrix([1, 2])
Out[6]:
<1x2 sparse matrix of type '<type 'numpy.int64'>'
        with 2 stored elements in Compressed Sparse Row format>

scipy.sparse.whatever_matrix_type(your_data_structure). It's quite analogous to what you'd do to get a regular array. Note that there is no sparse vector or sparse ndarray class, only sparse matrices.