The table below shows built-in exceptions that are usually raised in Python.

Remove List Duplicates Reverse a String Add Two Numbers · Python Examples Python Compiler Python Exercises Python Quiz Python Challenges Python Practice Problems Python Server Python Syllabus Python Study Plan Python Interview Q&A Python Training ... The try block lets you test a block of code for errors...

Many times though, a program results in an error after it is run even if it doesn't have any syntax error. Such an error is a runtime error, called an exception. A number of built-in exceptions are defined in the Python library. Let's see some common error types. The following table lists important built-in exceptions in Python.

The preceding part of the error message shows the context where the exception occurred, in the form of a stack traceback. In general it contains a stack traceback listing source lines; however, it will not display lines read from standard input.

Passing arguments of the wrong type (e.g. passing a list when an int is expected) should result in a TypeError, but passing arguments with the wrong value (e.g. a number outside expected boundaries) should result in a ValueError. ... Raised when a reference is made to a local variable in a function or method, but no value has been bound to that variable. This is a subclass of NameError. ... Raised when a Unicode-related encoding or decoding error occurs.

Tabs Dropdowns Accordions Side Navigation Top Navigation Modal Boxes Progress Bars Parallax Login Form HTML Includes Google Maps Range Sliders Tooltips Slideshow Filter List Sort List · HTML CSS JavaScript SQL Python PHP jQuery Bootstrap XML Read More » ... If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail: ... Your message has been sent to W3Schools.

August 7, 2025 - This article will teach you about some common Python errors you might encounter when running your code and how to fix it or handle it.

April 26, 2025 - Explanation: Expected output is that the average of a should be 30, but the program outputs 29.0. The logical error occurs because the formula b/ len(a) - 1 incorrectly subtracts 1, leading to an incorrect result. The correct formula should be b / len(a). Some of the common built-in exceptions are other than above mention exceptions are: Note: For more information, refer to Built-in Exceptions in Python

May 29, 2026 - SyntaxError: raised by the parser when the Python syntax is wrong. IndentationError: occurs when there is a wrong indentation. SystemError: raised when the interpreter detects an internal error. You can find a complete list of errors and exceptions in Python by reading the documentation.

HTML Certificate CSS Certificate ... Python Certificate PHP Certificate jQuery Certificate Java Certificate C++ Certificate C# Certificate XML Certificate ... W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot ...

Remove List Duplicates Reverse a String Add Two Numbers · Python Examples Python Compiler Python Exercises Python Quiz Python Challenges Python Practice Problems Python Server Python Syllabus Python Study Plan Python Interview Q&A Python Training ... The try block lets you test a block of code for errors...

Remove List Duplicates Reverse a String Add Two Numbers · Python Examples Python Compiler Python Exercises Python Quiz Python Challenges Python Practice Problems Python Server Python Syllabus Python Study Plan Python Interview Q&A Python Training ... As a Python developer you can choose to throw an exception if a condition occurs. To throw (or raise) an exception, use the raise keyword. Raise an error ...

main.py:2: error: "list[int]" has no attribute "lower" [attr-defined] Found 1 error in 1 file (checked 1 source file) While we have explored common Python errors and their solutions, it is important to recognize that errors are inevitable in any sufficiently complex program.

To learn more about them, visit Python try, except and finally statements. Errors represent conditions such as compilation error, syntax error, error in the logical part of the code, library incompatibility, infinite recursion, etc. Errors are usually beyond the control of the programmer and ...

HTML Certificate CSS Certificate ... Python Certificate PHP Certificate jQuery Certificate Java Certificate C++ Certificate C# Certificate XML Certificate ... W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot ...

You have to use the same number of spaces in the same block of code, otherwise Python will give you an error: ... Python has no command for declaring a variable. You will learn more about variables in the Python Variables chapter. Python has commenting capability for the purpose of in-code documentation. Comments start with a #, and Python will render the rest of the line as a comment: ... Coding fundamentals as a game. Bite-sized lessons and challenges. ... Ready to start your journey? Your streak is waiting. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com

HTML Certificate CSS Certificate ... Python Certificate PHP Certificate jQuery Certificate Java Certificate C++ Certificate C# Certificate XML Certificate ... W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot ...

January 12, 2025 - Error: -5 is not a valid age. Please choose an age between 0 and 130. ... Looking for an introduction to the theory behind programming? Master Python while learning data structures, algorithms, and more!