Reading And Writing Files

Exercise: Reading And Writing Files

How can you read and print the last 10 lines from a file named "log.txt"?

with open("log.txt", "r") as file:
    lines = file.readlines()
    for line in lines[-10:]:
        print(line)

print_last_lines("log.txt", 10)

with open("log.txt", "r") as file:
    print(file.tail(10))

with open("log.txt", "r") as file:
    for line in file:
        if line.number() > len(file) - 10:
            print(line)

Answer: A

Using list slicing to get the last 10 lines and printing them.

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What does the file.seek() method do?

Closes the file

Moves the file cursor to a specified position

Reads the file content

Truncates the file at the current position

Answer: B

file.seek() moves the file cursor to a specified position.

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How can you remove a file named "data.txt"?

remove_file("data.txt")

os.remove("data.txt")

delete_file("data.txt")

file.delete("data.txt")

Answer: B

Using os.remove() to remove a file in Python.

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How can you write a dictionary to a JSON file named "config.json"?

write_json("config.json", {"key": "value"})

with open("config.json", "w") as file:
    write_json(file, {"key": "value"})

json.write("config.json", {"key": "value"})

with open("config.json", "w") as file:
    json.dump({"key": "value"}, file)

Answer: D

Using open() in write mode and json.dump() to write a dictionary to a JSON file.

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What is the purpose of the file.truncate() method?

Closes the file

Truncates the file at the current position

Reads the file content

Writes the buffered data to the file

Answer: B

file.truncate() truncates the file at the current position.

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