对“ CSV”文件中的所有成绩进行平均的问题

Question

So I am new to python and I am having a hard time figuring this code. I am trying to use "CSV File" called exam_grades.csv and then write a function that reads in all my values in the file but using the string class split() method to split this long string into a list of strings. Each string represents a grade. Then my function should return the average of all the grades.

So far this is what I have; I can open the .csv file just fine but I'm having troubles averaging all the grades. I have some commented out because I am sure where to go from what I have been doing :(

def fileSearch():
    'Problem 4'
    readfile = open('exam_grades.csv', "r")
    for line in readfile:
        l = line.split(str(","))
        #num_grades = len(l)
        #averageAllGrades = l * 500 
        #return num_grades
        print(l)
fileSearch()

Any advice? Thanks!

Answer 1

Most CSV files have a header at the top, you'll want to skip that but for simplicity sake, let's say we ignore that.

Here's some code that works:

def fileSearch():
    'Problem 4'
    readfile = open('exam_grades.csv', "r")
    grade_sum = 0
    grade_count = 0
    for line in readfile:
        l = line.split(str(","))
        for grade in l:
            grade_sum += int(grade)
            grade_count += 1
    print(grade_sum/grade_count)

fileSearch()

This assumes you have multiple lines with grades and multiple grades per line.

We're keeping track of two variables here, the sum of all grades and the number of all grades we've added to the list (we're also casting to integers, since you're going to be reading strings).

When you add all the grades up and divide by the number of grades, you get an average.

Hope this helped.