class_docstr: Dataset class for NCF
class_docstr_tok: ["Dataset","class","for","NCF"]
code: def _create_negative_examples_df(self, user, user_negative_samples):
      # create dataframe containing negative examples for user assigned zero rating
      n_samples = len(user_negative_samples)
      return pd.DataFrame(
          {
              self.col_user: [user] * n_samples,
              self.col_item: user_negative_samples,
              self.col_rating: [0.0] * n_samples,
          }
      )
  
imports: import os
  from collections import OrderedDict
  import random
  import numpy
  import pandas
  import csv
  import logging
  from tqdm import tqdm
  from recommenders.utils.constants import DEFAULT_ITEM_COL, DEFAULT_USER_COL, DEFAULT_RATING_COL
label_desc: Use image node_id 2 for calling the Dataset obj's underlying member method code with example usage: obj._create_negative_examples_df(user, user_negative_samples) and returns: pd