Knowledge organisersFile Handling Techniques

Closing files

Knowledge organiser

File Handling Techniques

301.15d

Close file when done.

What you need to know

Files must be closed after use to ensure data is saved and system resources are freed. The with statement handles this automatically — it's the recommended approach.

Key points

Always close files when finished
with open() as f: closes automatically at end of block
Without with, you must call f.close() manually
Forgetting to close can lose data or lock the file

Code examples

Manual vs with

python

# Manual close (avoid)
f = open("data.txt", "r")
data = f.read()
f.close()

# Better: with auto-closes
with open("data.txt", "r") as f:
    data = f.read()
# File is already closed here