Project: save a study log

Create save_study_log.py in a practice folder. The program stores a list of session dictionaries in JSON and writes a text summary. Running it again replaces its two output files.

For file practice, download the Python practice files v1.0.0 bundle. The examples write their own files, so the samples stay unchanged. Work on a copy if you edit a sample.

Build the files

import json
from pathlib import Path

sessions = [
    {"subject": "Python", "minutes": 25},
    {"subject": "SQL", "minutes": 40},
]
json_path = Path("study_log.json")
summary_path = Path("study_summary.txt")

json_path.write_text(json.dumps(sessions, indent=2), encoding="utf-8")
loaded = json.loads(json_path.read_text(encoding="utf-8"))
total = sum(session["minutes"] for session in loaded)
summary_path.write_text(f"Sessions: {len(loaded)}\nTotal: {total} min\n", encoding="utf-8")
print(summary_path.read_text(encoding="utf-8").strip())

Sessions: 2
Total: 65 min

Why this works

The program writes a list of sessions to JSON, loads that file back, and computes a total from the loaded data. It writes a separate human-readable summary. This round trip checks that the stored data can be parsed, but it does not validate every possible malformed or unexpected file; Chapter 7 handles those failures.

Check and extend

Open both files and confirm they contain two sessions and a 65-minute total. Add a 15-minute Python session, rerun, and expect three sessions and 80 minutes.

Try another case

Why are study_log.json and study_summary.txt separate files?