SciPy

scipy.sparse.find

scipy.sparse.find(A)[source]

Return the indices and values of the nonzero elements of a matrix

Parameters:

A : dense or sparse matrix

Matrix whose nonzero elements are desired.

Returns:

(I,J,V) : tuple of arrays

I,J, and V contain the row indices, column indices, and values of the nonzero matrix entries.

Examples

>>> from scipy.sparse import csr_matrix
>>> A = csr_matrix([[7.0, 8.0, 0],[0, 0, 9.0]])
>>> find(A)
(array([0, 0, 1], dtype=int32), array([0, 1, 2], dtype=int32), array([ 7.,  8.,  9.]))