CODE EXAMPLE FOR PYTHON

delete csr python

import numpy as np
from scipy.sparse import csr_matrix

def delete_from_csr(mat, row_indices=[], col_indices=[]):
    """
    Remove the rows (denoted by ``row_indices``) and columns (denoted by ``col_indices``) from the CSR sparse matrix ``mat``.
    WARNING: Indices of altered axes are reset in the returned matrix
    """
    if not isinstance(mat, csr_matrix):
        raise ValueError("works only for CSR format -- use .tocsr() first")

    rows = []
    cols = []
    if row_indices:
        rows = list(row_indices)
    if col_indices:
        cols = list(col_indices)

    if len(rows) > 0 and len(cols) > 0:
        row_mask = np.ones(mat.shape[0], dtype=bool)
        row_mask[rows] = False
        col_mask = np.ones(mat.shape[1], dtype=bool)
        col_mask[cols] = False
        return mat[row_mask][:,col_mask]
    elif len(rows) > 0:
        mask = np.ones(mat.shape[0], dtype=bool)
        mask[rows] = False
        return mat[mask]
    elif len(cols) > 0:
        mask = np.ones(mat.shape[1], dtype=bool)
        mask[cols] = False
        return mat[:,mask]
    else:
        return mat