exercise8_5.py

#!/usr/bin/env python3
"""
Exercise  8.5: Write a program to read through the mail box data and when you
find the line that starts with "From", you will split the line into words
using the split function. We are interested in who sent the message, which is
second word on the From line.

From stephen.marquard@uct.ac.za Sat Jan 5 09:14:16 2008

You will parse the From line and print out the second word for each From line,
then you will also count the number of From (not From:) lines and print out a
count at the end.

This is a good sample output with a few lines removed:

python fromcount.py
Enter a file name: mbox-short.txt
stephen.marquard@uct.ac.za
louis@media.berkeley.edu
zqian@umich.edu

[... some output removed...]

ray@media.berkeley.edu
cwen@iupui.edu
cwen@iupui.edu
cwen@iupui.edu
There were 27 lines in the file with From as the first word

Python for Everybody: Exploring Data Using Python 3
by Charles R. Severance
"""


fhand = open('mbox-short.txt')
count = 0
for line in fhand:
    words = line.split()
    if len(words) < 3 or words[0] != 'From':
        continue
    print(words[1])
    count += 1
print('There were %d lines in the file with From as the first word' % count)