the file CSV_Reader_writer is code for read Csv table data like name (s1,s2,....) and each numbers in the same row and finally write each name and its average in the outfile mean_table https://realpython.com/python-csv/#parsing-csv-files-with-pythons-built-in-csv-library for generator and yeild acknowlegment: https://realpython.com/introduction-to-python-generators/#using-generators