HKDSE ICT File I/O: 6 Practice Problems with Solutions

Problem 1 — Count Lines

with open("notes.txt") as f:
    print(sum(1 for _ in f))

Problem 2 — Read Into List

with open("scores.txt") as f:
    scores = [int(line) for line in f]

Problem 3 — Append a Log Entry

from datetime import datetime
with open("log.txt", "a") as f:
    f.write(f"{datetime.now()}: started\n")

Problem 4 — Word Frequency

from collections import Counter
with open("article.txt") as f:
    words = f.read().lower().split()
print(Counter(words).most_common(5))

Problem 5 — Filter and Rewrite

with open("in.txt") as f, open("out.txt", "w") as g:
    for line in f:
        if not line.strip().startswith("#"):
            g.write(line)

Problem 6 — CSV Totals

import csv
with open("sales.csv") as f:
    reader = csv.DictReader(f)
    total = sum(float(row["amount"]) for row in reader)
print(f"Total: ${total:.2f}")