Raise statement
A raise statement is a language construct that explicitly signals an exception during program execution, optionally specifying the exception or its associated value.
The Quick Python Book, Fourth Edition
A raise statement explicitly signals an exception during program execution, optionally supplying an exception instance or class.
- How it is used
- Signals application-detected errors and directs execution toward a matching exception handler.
- How deep it goes
- Defines construction, message arguments, propagation, and handling, but defers broader exception-class design.
- Examples
- Uses an explicit IndexError, list-index failure, and EmptyFileError raised while processing files.
- What you can do after
- Apply it via Python to report detected conditions and route them to matching exception handlers.
Read how The Quick Python Book, Fourth Edition explains raise statement →
Python How-To
A raise statement is Python syntax that explicitly signals an exception during program execution.
- How it is used
- Signals invalid conditions explicitly and supplies messages that help users debug or handle exceptions.
- How deep it goes
- Explains bare and parameterized forms, syntactic sugar, exception instances, and concise messages, without detailing custom-class implementation.
- Examples
- Uses ValueError, ZeroDivisionError, formatted parameter messages, tracebacks, and a TypeError testing challenge.
- What you can do after
- Apply it via Python syntax to signal failures and provide concise diagnostic messages.
Related concepts
- exceptionproduces · An exception is a runtime signal or object representing an abnormal condition that interrupts ordinary program flow and may be handled or propagated.
- assertioncontrasts with · A software assertion is an executable check of an expected condition or property that signals failure when the check does not hold.
- type erroruses · A type error is a violation of a program’s type rules in which a value or expression has a type incompatible with an operation or context.
- keywordkind of · A keyword is a language-defined word or token with a predefined syntactic or semantic role, often restricted from use as an ordinary identifier.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.