finally — Expert Playground

Block that always executes after try/except, used for cleanup

Python Playground

import dis

def try_finally():
    try:
        x = 1
    finally:
        y = 2

def full_pattern():
    try:
        x = 1
    except ValueError:
        x = 2
    else:
        x = 3
    finally:
        x = 4

print("try/finally:")
dis.dis(try_finally)
print("\nfull pattern:")
dis.dis(full_pattern)

# The finally block is duplicated in the bytecode:
# once for the normal path and once for the exception path.
# This ensures it runs regardless of how the try exits.

Output

Click "Run" to execute your code

CPython duplicates the finally block's bytecode into both the normal and exception paths. SETUP_FINALLY pushes an entry onto the block stack that the VM uses to find the cleanup code.

Challenge

Try modifying the code above to explore different behaviors. Can you extend the example to handle a new use case?

View all Expert examples for finally