Python timer mystery. Python Exceptions Handling. Python provides two very important features to handle any unexpected error in your Python programs and to add debugging capabilities in them: Exception Handling: This would be covered in this tutorial. Here is a list standard Exceptions available in Python: Standard Exceptions. Assertions: This would be covered in Assertions in Python tutorial. What is Exception? An exception is an event, which occurs during the execution of a program, that disrupts the normal flow of the program's instructions. In general, when a Python script encounters a situation that it can't cope with, it raises an exception.
When a Python script raises an exception, it must either handle the exception immediately otherwise it would terminate and come out. Handling an exception: If you have some suspicious code that may raise an exception, you can defend your program by placing the suspicious code in a try: block. Syntax: Here is simple syntax of try....except...else blocks: Example: #! #! The try-finally clause: #!
#! #! Python Exception Handling Techniques - Doug Hellmann. Error reporting and processing through exceptions is one of Python’s key features. Care must be taken when handling exceptions to ensure proper application cleanup while maintaining useful error reporting. Error reporting and processing through exceptions is one of Python’s key features. Unlike C, where the common way to report errors is through function return values that then have to be checked on every invocation, in Python a programmer can raise an exception at any point in a program.
When the exception is raised, program execution is interrupted as the interpreter searches back up the stack to find a context with an exception handler. Throwing and Catching The statements used to deal with exceptions are raise and except. The arguments needed by the exception class vary, but usually include a message string to explain the problem encountered. For some scripts this behavior is sufficient, but it is nicer to catch the exception and print a more user-friendly version of the error.