Working with Files

Python's with statement closes files reliably, including when an error occurs.

Reading text

from pathlib import Path

path = Path("events.log")
text = path.read_text(encoding="utf-8")
print(text)

For large files, iterate line by line:

with path.open("r", encoding="utf-8", errors="replace") as handle:
    for line in handle:
        if "ERROR" in line:
            print(line.rstrip())

Writing safely

output = Path("report.txt")
output.write_text("Analysis complete\n", encoding="utf-8")

Before overwriting a file, confirm the destination and consider writing to a temporary file first. Never build privileged paths directly from untrusted input.

JSON data

import json

data = {"completed": True, "score": 10}
Path("progress.json").write_text(
    json.dumps(data, indent=2), encoding="utf-8"
)

Handle missing files, invalid encoding and malformed structured data explicitly.