Using dictionary to find the most sent emails from a file

[siliusu]

Thank you for your reply so much!
I tried the code. It shows traceback on "counter[address] += 1",saying it must be integers or slices, not str.

This is homework so special attention must be paid to terms and conditions.

- 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.

I have trouble understanding what is 'maximum loop', therefore I will use built-in max.

counter = dict()

with open('mbox-short.txt', 'r') as f:
    for line in f:
        if line.startswith('From '):
            address = line.split(maxsplit=2)[1]
            try:
                counter[address] += 1
            except KeyError:
                counter[address] = 1


print(max(counter, key=lambda rec: rec[1]))
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