How To Catch A Keyboardinterrupt in Python

In Python, KeyboardInterrupt is a built-in exception that occurs when the user interrupts the execution of a program using a keyboard action, typically by pressing Ctrl+C. Handling KeyboardInterrupt is crucial, especially in scenarios where a program involves time-consuming operations or user interactions. In this article, we’ll explore how to catch KeyboardInterrupt in Python.

Syntax

To catch a KeyboardInterrupt in Python, you can use a try-except block. The KeyboardInterrupt exception is raised when the user presses Ctrl+C, and you can handle it gracefully by incorporating the following syntax:

try:
    # Code that may raise KeyboardInterrupt
except KeyboardInterrupt:
    # Code to handle the KeyboardInterrupt

How to Catch A Keyboardinterrupt in Python?

Below, is an example that shows How To Catch A Keyboardinterrupt In Python.

Example 1: Basic KeyboardInterrupt Handling

Let’s consider a simple example where a program waits for user input, and we want to catch KeyboardInterrupt to exit the program gracefully:

In this example, the program continuously prompts the user for input. If the user interrupts the program with Ctrl+C, the KeyboardInterrupt exception is caught, and a message is displayed, gracefully terminating the program.

Python3

try:
    while True:
        user_input = input("Enter something (Ctrl+C to exit): ")
        print(f"You entered: {user_input}")
except KeyboardInterrupt:
    print("\nProgram terminated by user.")

Output

Enter something (Ctrl+C to exit): GeeksforGeeks
You entered: GeeksforGeeks
Program terminated by user.

Example 2: Handling KeyboardInterrupt in a Long-Running Process

In some cases, you may have a long-running process where you want to catch KeyboardInterrupt and perform cleanup operations before exiting. Consider the following example:

In this example, the long_running_process function simulates a process that takes some time to complete. If the user interrupts the process with Ctrl+C, the KeyboardInterrupt exception is caught, and a cleanup message is displayed before exiting.

Python3

import time

def long_running_process():
    try:
        print("Performing a long-running process. Press Ctrl+C to interrupt.")
        for i in range(10):
            time.sleep(1)
            print(f"Processing step {i + 1}")
    except KeyboardInterrupt:
        print("\nInterrupted! Cleaning up before exiting.")
        # Perform cleanup operations here if needed
    finally:
        print("Exiting the program.")

# Call the long_running_process function
long_running_process()

Output

Performing a long-running process. Press Ctrl+C to interrupt.
Processing step 1
Processing step 2
Processing step 3
Processing step 4
Processing step 5
Exiting the program.

Conclusion

Catching KeyboardInterrupt in Python is essential for handling user interruptions gracefully, especially in programs with time-consuming operations. By using a try-except block, you can effectively catch and handle KeyboardInterrupt, ensuring that your programs exit in a controlled manner. The provided examples illustrate how to implement KeyboardInterrupt handling in both basic user input scenarios and long-running processes.