File Errors and with

File Errors and with

In this tutorial, we'll use with and handle common file problems.

Files can fail for normal reasons:

• The file does not exist
• The path is wrong
• The program does not have permission
• The file is in a different folder

Python reports these problems with exceptions.

FileNotFoundError

try:
    with open("missing.txt", "r") as file:
        content = file.read()
except FileNotFoundError:
    print("That file does not exist")

This gives the user a helpful message instead of a long traceback.

Why with Matters

with closes the file automatically:

with open("notes.txt", "r") as file:
    content = file.read()

When the indented block ends, Python closes the file for you.

Without with, you need to remember to close it yourself:

file = open("notes.txt", "r")
content = file.read()
file.close()

The with version is safer and cleaner.

Keep File Code Small

Put only the file work inside the with block:

with open("scores.txt", "r") as file:
    lines = file.readlines()

for line in lines:
    print(line.strip())

The file is closed before the loop processes the lines.

Common Beginner Checklist

If file code fails, check:

• Is the filename spelled correctly?
• Is the file in the same folder as the Python script?
• Are you using the right mode?
• Did you accidentally use "w" when you meant "a"?

Most file errors become much easier once you check these basics slowly.

Practice

Try to read a file that does not exist. Catch FileNotFoundError and print a helpful message.