How to Print Exception Stack Traces in Python?

The suspicious code will be retained in the try block and handled by the except block in order to produce the stack trace for an exception. In order to handle the exception that was created, we shall output the stack trace here. Understanding the issue and the source of the code mistake is aided by the publishing stack trace for an exception. Not only that, but the stack trace also indicates the error's location.

The general format of an error stack trace is as follows:

• The call traceback for the latest instance.
• The program's location.
• Line in the software where the mistake occurred.
• Name of the error: pertinent details regarding the exception.

Example:

Method 1: By Using the print_exc() Method

This function stacks trace entries from the traceback object (tb) and prints exception information to a file.

Syntax:

Parameters: The following arguments are accepted by this method:

• If there is a positive limit argument, Print from the Traceback object tb up to the limit of stack trace entries (beginning at the caller's frame). Print the final abs(limit) entries if not. Every entry is displayed in the event that the limit argument is None.
• The output is sent to sys. stderr if the file parameter is None; otherwise, the output should be sent to an open file or file-like object.
• Similar to how the interpreter prints an unhandled exception, chained exceptions will also be printed if the chain parameter is true (the default).

Return: None.

Code:

Program Explanation:

Using exception handling, the Python program illustrates how to handle an index error that arises while attempting to access an element at index (5) that is beyond the boundaries of the array 'A.' The program tries to access 'A[5],' and if an exception arises, it sends a traceback inside the try block. The stack trace, which contains details about the exception, is printed using the print_exc() function. It outputs the IndexError and the associated stack trace in this instance. The code that follows the try-except block is performed even when an exception is handled inside the try block because the program still runs in spite of the exception, and the message "end of program" is printed.

Output:

Traceback (most recent call last):
  File "C:/Python27/hdg.py", line 8, in 
    value=A[5]
IndexError: list index out of range
end of program

Method 2: By Using the print_exception() Method

This function stacks trace entries from the traceback object (tb) and prints exception information to a file.

Syntax:

Parameters: The following parameters are accepted by his method:

• When the tb argument is None, the header Traceback (the last call made most recently) is printed:
• Following the stack trace, it outputs the exception's etype and value.
• It outputs the line containing the syntax error along with a caret indicating the approximate location of the error if the type(value) parameter is SyntaxError and the value is in the correct format.
• Suppose there is a positive limit argument, Print from the Traceback object tb up to the limit of stack trace entries (beginning at the caller's frame). Print the final abs(limit) entries if not. Every entry is displayed in the event that the limit argument is None.
• The output is sent to sys. stderr if the file parameter is None; otherwise, the output should be sent to an open file or file-like object.
• Similar to how the interpreter prints an unhandled exception, chained exceptions will also be printed if the chain parameter is true (the default).

Return: None.

Code:

Program Explanation:

This Python program illustrates how to handle exceptions in the case of a division by zero. The program tries to execute the operation a / b inside the try block, where 'a' is initialized to 4 and 'b' to 0. An exception is raised as dividing by zero is prohibited. The exception and Traceback are caught by the except block. The stack trace is printed using the print_exception(*sys.exc_info()) function, which also provides the exception's type, value, and Traceback. The code after the try-except block is performed even if an exception is handled within the try block since the program still runs and the message "end of program" is written in spite of the exception.

Output:

Traceback (most recent call last):
  File "C:/Python27/hdg.py", line 10, in 
    value=a/b
ZeroDivisionError: integer division or modulo by zero
end of program