How do you write data from a list into a CSV file?

Question

I have been given a an original csv file, and tasked with reading it, adding a new column for average and then writing the updated data back out to another csv file.

Everything has been successful up to the writing of the data from the list.

"""Student Do: Sales Analysis.

This script will use the Pathlib library to set the file path,
use the csv library to read in the file, and iterate over each
row of the file to calculate customer sales averages.
"""

# @TODO: Import the pathlib and csv library
from pathlib import Path
import csv

# @TODO: Set the file path
csv_path = Path("Resources/sales.csv")

# Initialize list of records
records = []

# @TODO: Open the csv file as an object
with open (csv_path, 'r') as csv_file:

    # @TODO:
    # Pass in the csv file to the csv.reader() function
    # (with ',' as the delmiter/separator) and return the csvreader object
    csv_reader = csv.reader(csv_file, delimiter=',')
    # @TODO: Read the header row
    header = next(csv_reader)
    # @TODO: Print the header


    # @TODO: Append the column 'Average' to the header
    header.append('Average')
    print (header)

    # @TODO: Append the header to the list of records
    records.append(header)

    # @TODO: Read each row of data after the header
    for row in csv_reader:
        # @TODO: Print the row
        #print(row)
        # @TODO:
        # Set the 'name', 'count', 'revenue' variables for better
        # readability, convert strings to ints for numerical calculations
        name = row[0]
        count = int(row[1])
        revenue = int(row[2])
        records.append(name)
        records.append(count)
        records.append(revenue)


        # @TODO: Calculate the average (round to the nearest 2 decimal places)
        average = round(revenue/count, 2)

        # @TODO: Append the average to the row
        row.append(average)
        # @TODO: Append the row to the list of records
        records.append(row[3])
        print (row)

        
# @TODO: Set the path for the output.csv
csv_output_path = Path("output.csv")

# @TODO:
# Open the output path as a file and pass into the 'csv.writer()' function
# Set the delimiter/separater as a ','
with open (csv_output_path, 'w') as file:
    csv_writer = csv.writer(file, delimiter=',')
    # @TODO:
    # Loop through the list of records and write every record to the
    # output csv file
    csv_writer.writerow(header)
    for row in records:
        csv_writer.writerow(records)
        
for data in records:
    print (data)

The output file is all wrong, the header is in the name section, the name is in the count section, the count is in revenue and everything else is in the average section

Answer 1

replace csv_writer.writerow(records) with csv_writer.writerow(row)