Data Management & Integration Flashcards

Which pandas method removes duplicate rows from a DataFrame?

Answer: drop_duplicates()

drop_duplicates() returns a DataFrame with duplicate rows removed, keeping the first occurrence by default.

In Python's csv module, which class is used to write rows to a CSV file?

Answer: csv.writer

csv.writer() creates a writer object whose writerow() or writerows() methods write data to a CSV file.

What is the role of 'transactions' in database management when using Python's sqlite3 module?

Answer: They group SQL operations so all succeed or all fail atomically

A transaction groups multiple SQL statements into an atomic unit; if any statement fails, a rollback reverts all changes.

Which pandas method writes a DataFrame to an Excel file?

Answer: df.to_excel()

df.to_excel() exports a DataFrame to an .xlsx file, requiring the openpyxl library to be installed.

What does the 'dtype' parameter control in pd.read_csv()?

Answer: The data type assigned to one or more columns on import

Passing dtype={'col': str} forces pandas to parse the specified columns as the given data type instead of inferring them.

In SQLAlchemy Core, which function is used to construct a SELECT statement programmatically?

Answer: sqlalchemy.select()

sqlalchemy.select() builds a SELECT SQL expression that can be executed against a connection.

When writing a large DataFrame to a SQL database with pandas, which method is most appropriate?

Answer: df.to_sql()

df.to_sql() writes a DataFrame to a SQL table using an SQLAlchemy engine or sqlite3 connection, with options for if_exists and chunksize.