class_docstr: Data processing class for GCN models which use implicit feedback.
  
  Initialize train and test set, create normalized adjacency matrix and sample data for training epochs.
docstr: Process the dataset to reindex userID and itemID and only keep records with ratings greater than 0.
  
  Args:
      df (pandas.DataFrame): dataframe with at least columns (col_user, col_item, col_rating).
  
  Returns:
      list: train and test pandas.DataFrame Dataset, which have been reindexed and filtered.
docstr_tok: ["Process","the","dataset","to","reindex","userID","and","itemID","and","only","keep","records","with","ratings","greater","than","0",".","Args",":","df","(","pandas.DataFrame",")",":","dataframe","with","at","least","columns","(","col_user",",","col_item",",","col_rating",")",".","Returns",":","list",":","train","and","test","pandas.DataFrame","Dataset",",","which","have","been","reindexed","and","filtered","."]
code: def _reindex(self, df):
      """Process the dataset to reindex userID and itemID and only keep records with ratings greater than 0.
  
      Args:
          df (pandas.DataFrame): dataframe with at least columns (col_user, col_item, col_rating).
  
      Returns:
          list: train and test pandas.DataFrame Dataset, which have been reindexed and filtered.
  
      """
  
      if df is None:
          return None
  
      df = pd.merge(df, self.user_idx, on=self.col_user, how="left")
      df = pd.merge(df, self.item_idx, on=self.col_item, how="left")
  
      df = df[df[self.col_rating] > 0]
  
      df_reindex = df[
          [
              self.col_user + "_idx",
              self.col_item + "_idx",
              self.col_rating,
          ]
      ]
      df_reindex.columns = [
          self.col_user,
          self.col_item,
          self.col_rating,
      ]
  
      return df_reindex
  
file_path: recommenders/recommenders/models/deeprec/DataModel/ImplicitCF.py
imports: import random
  import numpy
  import pandas
  import scipy.sparse
  from recommenders.utils.constants import DEFAULT_ITEM_COL, DEFAULT_USER_COL, DEFAULT_RATING_COL, DEFAULT_PREDICTION_COL
label_desc: Use image node_id 3 for calling the ImplicitCF obj's underlying member method code with example usage: obj._reindex(df) and returns: df_reindex, None