Capture and Print Python Exception Message

In Python, you can capture and print exception messages using try and except blocks in multiple ways, such as -

• Using the as keyword
• Using the type() function
• Using the traceback module

Exception messages provide details about what went wrong, which is helpful for debugging and error handling.

Using the 'as' Keyword

You can assign the exception to a variable using the as keyword inside the except block. This allows you to access and print the actual error message.

Example: Capturing ZeroDivisionError message

In this example, we divide a number by zero and print the exception message -

try:
   result = 10 / 0
except ZeroDivisionError as e:
   print("Exception message:", e)

We get the following output -

Exception message: division by zero

Using print() and type() Functions with Exception

You can also use the type() function to get the type of exception and the print() function to display both the type and the message for better debugging.

Example: Displaying type and message

In this example, we try to access an undefined variable, which raises a NameError -

try:
   print(x)
except Exception as e:
   print("Error type:", type(e).__name__)
   print("Error message:", e)

The output will be -

Error type: NameError
Error message: name 'x' is not defined

Using traceback Module

Python's traceback module gives more detailed information, including the exact line where the error occurred, which helps in debugging complex programs.

Example

In this example, we import traceback module in Python and print the full stack trace -

import traceback

try:
   a = 5 / 0
except Exception as e:
   print("Exception message:", e)
   traceback.print_exc()

The output includes the exception message and the traceback -

Exception message: division by zero
Traceback (most recent call last):
  ...
ZeroDivisionError: division by zero

Storing Exception Message in a Variable

You can also store the exception message in a variable if you want to use it later in your code, such as logging or displaying it to users.

Example: Storing and using exception message

In this example, we store the message and use it to build a user-friendly output -

try:
   int("abc")
except ValueError as e:
   error_msg = str(e)
   print("An error occurred:", error_msg)

We get the following output -

An error occurred: invalid literal for int() with base 10: 'abc'