Description

Login

Syncing account progress…

Back

Intermediate · 12 min

Handling errors

Recover from expected problems with focused exception handling.

Catch a specific error

Put the operation that may fail inside try. Catch only the exception you expect so unrelated bugs remain visible.

try:
    number = int("six")
except ValueError:
    number = 0
print(number)

Output

0

Use else after success

The else block runs only when the try block completes without an exception.

try:
    value = int("12")
except ValueError:
    print("Invalid")
else:
    print(value * 2)

Output

24

Handling errors

  1. Read both handling errors examples before answering.
  2. Run the task, compare its exact output, and revise the code if needed.

Try it yourself

Code runs on this device. When you are signed in, drafts sync to your account.

Safe conversion

Complete to_number so it returns the integer value for valid text and -1 for invalid text. Display both supplied calls.

Practice