{"id":884,"date":"2020-10-29T06:36:47","date_gmt":"2020-10-29T06:36:47","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=884"},"modified":"2025-03-30T10:26:52","modified_gmt":"2025-03-30T10:26:52","slug":"python-try-except-finally","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-basics\/python-try-except-finally\/","title":{"rendered":"Python try…except…finally"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about the Python try...except...finally<\/code> statement.<\/p>\n\n\n\n

Introduction to Python try…except…finally statement #<\/a><\/h2>\n\n\n\n

The try...except<\/code> statement allows you to catch one or more exceptions<\/a> in the try<\/code> clause and handle each of them in the except<\/code> clauses.<\/p>\n\n\n\n

The try...except<\/code> statement also has an optional clause called finally<\/code>:<\/p>\n\n\n

try<\/span>:\n    # code that may cause exceptions<\/span>\nexcept:\n    # code that handle exceptions<\/span>\nfinally<\/span>:\n    # code that clean up<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The finally<\/code> clause always executes whether an exception occurs or not. And it executes after the try<\/code> clause and any except<\/code> clause.<\/p>\n\n\n\n
The following flowchart illustrates the try...except...finally<\/code> clause:<\/p>\n\n\n
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\"Python<\/figure>\n<\/div>\n\n\n
Python try…except…finally statement examples #<\/a><\/h2>\n\n\n\n
The following example uses the try...except...finally<\/code> statement:<\/p>\n\n\n
a = 10<\/span>\nb = 0<\/span>\n\ntry<\/span>:\n    c = a \/ b\n    print<\/span>(c)\nexcept ZeroDivisionError as<\/span> error:\n    print<\/span>(error)\nfinally<\/span>:\n    print<\/span>('Finishing up.'<\/span>)\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
division by zero\nFinishing up.<\/code><\/span><\/pre>\n\n\n
In this example, the try<\/code> clause causes a ZeroDivisionError<\/code> exception both except<\/code> and finally<\/code> clause executes.<\/p>\n\n\n\n
The try<\/code> clause in the following example doesn’t cause an error. Therefore, all statements in the try<\/code> and finally<\/code> clauses execute:<\/p>\n\n\n
a = 10<\/span>\nb = 2<\/span>\n\ntry<\/span>:\n    c = a \/ b\n    print<\/span>(c)\nexcept ZeroDivisionError as<\/span> error:\n    print<\/span>(error)\nfinally<\/span>:\n    print<\/span>('Finishing up.'<\/span>)\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
5.0<\/span>\nFinishing<\/span> up<\/span>.<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Python try…finally statement #<\/a><\/h2>\n\n\n\n
The catch<\/code> clause in the try...except...finally<\/code> statement is optional. So you can write it like this:<\/p>\n\n\n
try<\/span>:\n    # the code that may cause an exception<\/span>\nfinally<\/span>:\n    # the code that always executes<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Typically, you use this statement when you cannot handle the exception but you want to clean up resources. For example, you want to close the file that has been opened.<\/p>\n\n\n\n
Summary #<\/a><\/h2>\n\n\n\n