7.2 Write a program that prompts for a file name, then opens that file and reads through the file, looking for lines of the form:
Count these lines and extract the floating-point values from each of the lines and compute the average of those values and produce an output as shown below. Do not use the sum() function or a variable named sum in your solution.
You can download the sample data at http://www.py4e.com/code3/mbox-short.txt when you are testing below enter mbox-short.txt as the file name.
# Use the file name mbox-short.txt as the file name
fname = input("Enter file name: ")
fh = open(fname)
count = 0
s = 0
for line in fh:
if not line.startswith("X-DSPAM-Confidence:") :
pos = line.find('0')
s += float(line[pos:pos+6])
count += 1
average = s / count
print("Average spam confidence:", average)