Struct PyValueError

pub struct PyValueError(/* private fields */);

Represents Python’s ValueError exception.

Example: Raising ValueError from Rust

This exception can be sent to Python code by converting it into a PyErr, where Python code can then catch it.

use pyo3::prelude::*;
use pyo3::exceptions::PyValueError;

#[pyfunction]
fn always_throws() -> PyResult<()> {
    let message = "I'm ValueError, and I was raised from Rust.";
    Err(PyValueError::new_err(message))
}

Python code:

from my_module import always_throws

try:
   always_throws()
except ValueError as e:
   print(f"Caught an exception: {e}")

Example: Catching ValueError in Rust

use pyo3::prelude::*;
use pyo3::exceptions::PyValueError;

Python::with_gil(|py| {
    let result: PyResult<()> = py.run_bound("raise ValueError", None, None);

    let error_type = match result {
        Ok(_) => "Not an error",
        Err(error) if error.is_instance_of::<PyValueError>(py) => "ValueError",
        Err(_) => "Some other error",
    };

    assert_eq!(error_type, "ValueError");
});

Implementations

impl PyValueError

pub fn new_err<A>(args: A) -> PyErr

where A: PyErrArguments + Send + Sync + 'static,

Creates a new PyErr of this type.

Trait Implementations

impl AsPyPointer for PyValueError

fn as_ptr(&self) -> *mut PyObject

Gets the underlying FFI pointer, returns a borrowed pointer.

impl AsRef<PyAny> for PyValueError

fn as_ref(&self) -> &PyAny

Converts this type into a shared reference of the (usually inferred) input type.

impl Deref for PyValueError

type Target = PyAny

The resulting type after dereferencing.

fn deref(&self) -> &PyAny

Dereferences the value.

impl PyTypeInfo for PyValueError

const NAME: &'static str = "PyValueError"

Class name.

const MODULE: Option<&'static str> = _

Module name, if any.

fn type_object_raw(py: Python<'_>) -> *mut PyTypeObject

Returns the PyTypeObject instance for this type.

fn type_object_bound(py: Python<'_>) -> Bound<'_, PyType>

Returns the safe abstraction over the type object.

fn is_type_of_bound(object: &Bound<'_, PyAny>) -> bool

Checks if object is an instance of this type or a subclass of this type.

fn is_exact_type_of_bound(object: &Bound<'_, PyAny>) -> bool

Checks if object is an instance of this type.

impl DerefToPyAny for PyValueError

impl PyLayout<PyValueError> for PyBaseExceptionObject

impl PySizedLayout<PyValueError> for PyBaseExceptionObject

impl ToPyErr for PyValueError