Python exception handling
- 1. Exception Handling in Python Mohammed Sikander
- 2. Python Exceptions Exception Handling Try and Except Nested try Block Handling Multiple Exceptions in single Except Block Raising Exception Finally Block User Defined Exceptions
- 3. Exception When writing a program, we, more often than not, will encounter errors. Error caused by not following the proper structure (syntax) of the language is called syntax error or parsing error Errors can also occur at runtime and these are called exceptions. They occur, for example, when a file we try to open does not exist (FileNotFoundError), dividing a number by zero (ZeroDivisionError) Whenever these type of runtime error occur, Python creates an exception object. If not handled properly, it prints a traceback to that error along with some details about why that error occurred.
- 5. Exception Handling To handle exceptions, and to call code when an exception occurs, we can use a try/except statement. The try block contains code that might throw an exception. If that exception occurs, the code in the try block stops being executed, and the code in the except block is executed. If no error occurs, the code in the except block doesn't execute.
- 9. A try statement can have multiple different except blocks to handle different exceptions.
- 12. Multiple exceptions can also be put into a single except block using parentheses, to have the except block handle all of them.
- 17. Raising Exception from Except Block
- 18. finally To ensure some code runs no matter what errors occur, you can use a finally statement. The finally statement is placed at the bottom of a try/except statement. Code within a finally statement always runs after execution of the code in the try, and possibly in the except, blocks.
- 21. Code in a finally statement even runs if an uncaught exception occurs in one of the preceding blocks.
- 22. Raising Exception Raising exception is similar to throwing exception in C++/Java. You can raise exceptions by using the raise statement