7-2

#! /usr/bin/env python3.2
# -*- coding: utf-8 -*-

# main.py
""" Task: Exercise 7.2
    Write a program to prompt for a file name an then read through the file
    and look for lines of the form:
    X-DSPAM-Confidence: 0.8475
    When you encounter a line that starts with “X-DSPAM-Confidence:” pull apart
    the line to extract the floating point number on the line. Count these
    lines and the compute the total of the spam confidence values from these
    lines. When you reach the end of the file, print out the average spam
    confidence.
    Enter the file name: mbox.txt
    Average spam confidence: 0.894128046745
    Enter the file name: mbox-short.txt
    Average spam confidence: 0.750718518519
    Test your file on the mbox.txt and mbox-short.txt files.
"""

''' Functions '''
def enterFileName():
    """
    The user has to enter a filename.
    Returns fileName
    """
    fileName = None
    while fileName == None:
        # Enter filename
        try:
            fileName = input("Enter the filename: ")
        except:
            print("Invalid input!")
            continue
    return fileName
# End of enterFileName()

''' Main '''
file = None
totalSpam = 0
spamCounter = 0
spamAverage = 0
fileName = enterFileName()

try:
    file = open(fileName, 'r')      # Open file
except:
    print("File cannot be opened: " + str(fileName))
    exit()
if file != None:
    try:
        for line in file:           # Read file content
            if line.startswith("X-DSPAM-Confidence:"):
                try:
                    totalSpam += float(line[20:-1])
                    spamCounter += 1
                except:
                    continue
    except:
       print("Error on reading file content!")
    spamAverage = totalSpam / spamCounter
    print("Average spam confidence: " + str(spamAverage))
    try:
        file.close()                # Close file
    except:
        print("File could not be closed!")
        exit()