Question

average_value_in_file / Python 3.x: Your assistance is appreciated, thank you!

Write a function named average_value_in_file that accepts a file name as a parameter and reads that file, assumed to be full of numbers, and returns the average (mean) of the numbers in that file. The parameter, filename, gives the name of a file that contains a list of numbers, one per line. You may assume that the file exists and follows the proper format. For example, if a file named input.txt contains the following numbers

1.5
2.75
9.0
-3.25
0.0
6.5

Then the call of average_value_in_file("input.txt") should return 2.75.

You may assume that the input file exists and is in the proper format. If the file does not contain any input values, return 0.0.

Constraints: Your solution should read the file only once, not make multiple passes over the file data.

This is a function exercise. Write a Python function as described. Do not write a complete program; just the function(s) above.

Answer 1

def average_value_in_file(filename):
    f = open(filename)
    total = 0
    count = 0
    for line in f:
        num = float(line.strip())
        total += num
        count += 1
    f.close()
    if count == 0:
        return 0.0
    else:
        return total / count