CODE EXAMPLE FOR PYTHON

delete csr python

def delete_row_csr(mat, i):
    if not isinstance(mat, scipy.sparse.csr_matrix):
        raise ValueError("works only for CSR format -- use .tocsr() first")
    n = mat.indptr[i+1] - mat.indptr[i]
    if n > 0:
        mat.data[mat.indptr[i]:-n] = mat.data[mat.indptr[i+1]:]
        mat.data = mat.data[:-n]
        mat.indices[mat.indptr[i]:-n] = mat.indices[mat.indptr[i+1]:]
        mat.indices = mat.indices[:-n]
    mat.indptr[i:-1] = mat.indptr[i+1:]
    mat.indptr[i:] -= n
    mat.indptr = mat.indptr[:-1]
    mat._shape = (mat._shape[0]-1, mat._shape[1])