Create two columns with the indexes for the names Here we use an existing lookup table. Should be used in predicting
create_index_with_existing_lookup_table(d, player0, player1, lookup_table)
A data frame containing the observations. The other parameters specify the name of the columns
The name of the column of data data contains player0
The name of the column of data data contains player0
lookup_table a lookup table data frame
A dataframe with the additional columns 'player0_index' and 'player1_index' that contains the indexes