9.4 Write a program to read through the mbox-short.txt and figure out who has sent the greatest number of mail messages. The program looks for 'From ' lines and takes the second word of those lines as the person who sent the mail. The program creates a Python dictionary that maps the sender's mail address to a count of the number of times they appear in the file. After the dictionary is produced, the program reads through the dictionary using a maximum loop to find the most prolific committer.

name = input("Enter file:")

if len(name) < 1 : name = "mbox-short.txt"

fh = open(name)

from_lines = []

emails = {}

for line in fh:

    line = line.rstrip()

    if line.find('From ') == 0:

        line = line.split(' ')

        email = line[1]

        if email not in emails:

            emails[email] = 1

        else:

            emails[email] += 1

email = ''

count = 0

for key in emails:

    if emails[key] > count:

        count = emails[key]

        email = key

print(email, str(count))