Why Am I Getting a \'KeyError: \'review\'\' When Accessing a Pandas DataFrame?

Pandas KeyError: Troubleshooting 'review' Column Access Error

The error "pandas hashtable keyerror" occurs when attempting to access a nonexistent column within a pandas DataFrame. In the given code snippet, the attempt to print the 'review' column fails due to a key error. This error suggests that the column name is incorrect or misspelled.

To resolve this issue, it's essential to verify the actual column names of the DataFrame. One way to do this is to print the list of column names:

print(reviews_new.columns.tolist())

The output of this command will reveal the actual column names.

Potential Causes of the KeyError:

1. Whitespace in Column Names: There may be extraneous whitespace in the column names, including trailing or leading spaces. To remove this, try stripping the whitespace from the column names:

reviews_new.columns = reviews_new.columns.str.strip()

2. Incorrect Separator: The default separator used by pandas when reading CSV files is a comma (,). If a different separator is used in the CSV file, specify it using the 'sep' parameter:

reviews_new = pd.read_csv("D:\aviva.csv", sep=';')

3. Unnamed Columns: Another possibility is that the column names in the CSV file are not defined. In this case, the columns will be assigned default names such as 'Unnamed: 0', 'Unnamed: 1', and so on. To access these columns, use the DataFrame's index instead:

print(reviews_new.index.get_level_values('Unnamed: 0'))

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