Average of a list in Python

Question

I have a file "list1" that contain Name, Surname, Note1, Note2, like this:

DUPOND, John, 12, 10
JAMES, Fil, 8, 10
KYLE, Gregor, 17, 7

I want to write a Python script to display in another file called "list2", the content of "list1" but sorted and with the average of the 2 notes in the format : Surname, Name, Note1, Note2, Average like this:

John, DUPOND, 12, 14, 13
JAMES, Fil, , 8, 10, 9
KYLE, Gregor, 17, 7, 12

Do you have advice to give ?

I have tested this code it's only display the content of my file in square bracket, how can i make the average of the 2 value and put it in another file?

import sys
import csv

with open(sys.argv[1], newline='') as f:
    reader = csv.reader(f)
    for row in reader:
     statistics.mean(xs)
        print(row)

Answer 1

The steps involved here are:

1. Read a row, unpack the name components and the values separately
2. Compute the mean of the values (which will require converting them to int; csv reads them as str)
3. Write out the name components in reverse order, the values, and the mean

import sys
import csv
import statistics

with open(sys.argv[1], newline='') as inf, open(sys.argv[2], 'w', newline='') as outf:
    writer = csv.writer(outf)
    for name, surname, *values in csv.reader(inf):  # Read name first, surname second, then collect values
        writer.writerow([surname, name, *values, statistics.mean(map(int, values))])  # Write surname first, then name, then values, then average

This works even if the number of values is something other than two, since the unpacking handles all extra values by collecting them into the values list, however many there may be.