Struct PyWeakrefReference

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

Represents a Python weakref.ReferenceType.

In Python this is created by calling weakref.ref.

Implementations

impl PyWeakrefReference

pub fn new_bound<'py>( object: &Bound<'py, PyAny>, ) -> PyResult<Bound<'py, PyWeakrefReference>>

Constructs a new Weak Reference (weakref.ref/weakref.ReferenceType) for the given object.

Returns a TypeError if object is not weak referenceable (Most native types and PyClasses without weakref flag).

Examples

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

Python::with_gil(|py| {
    let foo = Bound::new(py, Foo {})?;
    let weakref = PyWeakrefReference::new_bound(&foo)?;
    assert!(
        // In normal situations where a direct `Bound<'py, Foo>` is required use `upgrade::<Foo>`
        weakref.upgrade()
            .map_or(false, |obj| obj.is(&foo))
    );

    let weakref2 = PyWeakrefReference::new_bound(&foo)?;
    assert!(weakref.is(&weakref2));

    drop(foo);

    assert!(weakref.upgrade().is_none());
    Ok(())
})

pub fn new_bound_with<'py, C>( object: &Bound<'py, PyAny>, callback: C, ) -> PyResult<Bound<'py, PyWeakrefReference>>

where C: ToPyObject,

Constructs a new Weak Reference (weakref.ref/weakref.ReferenceType) for the given object with a callback.

Returns a TypeError if object is not weak referenceable (Most native types and PyClasses without weakref flag) or if the callback is not callable or None.

Examples

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

#[pyfunction]
fn callback(wref: Bound<'_, PyWeakrefReference>) -> PyResult<()> {
        let py = wref.py();
        assert!(wref.upgrade_as::<Foo>()?.is_none());
        py.run_bound("counter = 1", None, None)
}

Python::with_gil(|py| {
    py.run_bound("counter = 0", None, None)?;
    assert_eq!(py.eval_bound("counter", None, None)?.extract::<u32>()?, 0);
    let foo = Bound::new(py, Foo{})?;

    // This is fine.
    let weakref = PyWeakrefReference::new_bound_with(&foo, py.None())?;
    assert!(weakref.upgrade_as::<Foo>()?.is_some());
    assert!(
        // In normal situations where a direct `Bound<'py, Foo>` is required use `upgrade::<Foo>`
        weakref.upgrade()
            .map_or(false, |obj| obj.is(&foo))
    );
    assert_eq!(py.eval_bound("counter", None, None)?.extract::<u32>()?, 0);

    let weakref2 = PyWeakrefReference::new_bound_with(&foo, wrap_pyfunction_bound!(callback, py)?)?;
    assert!(!weakref.is(&weakref2)); // Not the same weakref
    assert!(weakref.eq(&weakref2)?);  // But Equal, since they point to the same object

    drop(foo);

    assert!(weakref.upgrade_as::<Foo>()?.is_none());
    assert_eq!(py.eval_bound("counter", None, None)?.extract::<u32>()?, 1);
    Ok(())
})

impl PyWeakrefReference

pub fn new<T>(object: &T) -> PyResult<&PyWeakrefReference>

where T: PyNativeType,

👎Deprecated since 0.21.0: PyWeakrefReference::new will be replaced by PyWeakrefReference::new_bound in a future PyO3 version

Available on crate feature gil-refs only.

Deprecated form of PyWeakrefReference::new_bound.

pub fn new_with<T, C>(object: &T, callback: C) -> PyResult<&PyWeakrefReference>

where T: PyNativeType, C: ToPyObject,

👎Deprecated since 0.21.0: PyWeakrefReference::new_with will be replaced by PyWeakrefReference::new_bound_with in a future PyO3 version

Available on crate feature gil-refs only.

Deprecated form of PyWeakrefReference::new_bound_with.

pub fn upgrade_as<T>(&self) -> PyResult<Option<&T::AsRefTarget>>

where T: PyTypeCheck,

Available on crate feature gil-refs only.

Upgrade the weakref to a direct object reference.

It is named upgrade to be inline with rust’s Weak::upgrade. In Python it would be equivalent to PyWeakref_GetObject or calling the weakref.ReferenceType (result of calling weakref.ref).

Example

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

#[pymethods]
impl Foo {
    fn get_data(&self) -> (&str, u32) {
        ("Dave", 10)
    }
}

fn parse_data(reference: Borrowed<'_, '_, PyWeakrefReference>) -> PyResult<String> {
    if let Some(data_src) = reference.upgrade_as::<Foo>()? {
        let data = data_src.borrow();
        let (name, score) = data.get_data();
        Ok(format!("Processing '{}': score = {}", name, score))
    } else {
        Ok("The supplied data reference is nolonger relavent.".to_owned())
    }
}

Python::with_gil(|py| {
    let data = Bound::new(py, Foo{})?;
    let reference = PyWeakrefReference::new_bound(&data)?;

    assert_eq!(
        parse_data(reference.as_borrowed())?,
        "Processing 'Dave': score = 10"
    );

    drop(data);

    assert_eq!(
        parse_data(reference.as_borrowed())?,
        "The supplied data reference is nolonger relavent."
    );

    Ok(())
})

Panics

This function panics is the current object is invalid. If used propperly this is never the case. (NonNull and actually a weakref type)

pub unsafe fn upgrade_as_unchecked<T>(&self) -> Option<&T::AsRefTarget>

where T: PyTypeCheck,

Available on crate feature gil-refs only.

Upgrade the weakref to a direct object reference unchecked. The type of the recovered object is not checked before downcasting, this could lead to unexpected behavior. Use only when absolutely certain the type can be guaranteed. The weakref may still return None.

It is named upgrade to be inline with rust’s Weak::upgrade. In Python it would be equivalent to PyWeakref_GetObject or calling the weakref.ReferenceType (result of calling weakref.ref).

Safety

Callers must ensure that the type is valid or risk type confusion. The weakref is still allowed to be None, if the referenced object has been cleaned up.

Example

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

#[pymethods]
impl Foo {
    fn get_data(&self) -> (&str, u32) {
        ("Dave", 10)
    }
}

fn parse_data(reference: Borrowed<'_, '_, PyWeakrefReference>) -> String {
    if let Some(data_src) = unsafe { reference.upgrade_as_unchecked::<Foo>() } {
        let data = data_src.borrow();
        let (name, score) = data.get_data();
        format!("Processing '{}': score = {}", name, score)
    } else {
        "The supplied data reference is nolonger relavent.".to_owned()
    }
}

Python::with_gil(|py| {
    let data = Bound::new(py, Foo{})?;
    let reference = PyWeakrefReference::new_bound(&data)?;

    assert_eq!(
        parse_data(reference.as_borrowed()),
        "Processing 'Dave': score = 10"
    );

    drop(data);

    assert_eq!(
        parse_data(reference.as_borrowed()),
        "The supplied data reference is nolonger relavent."
    );

    Ok(())
})

Panics

This function panics is the current object is invalid. If used propperly this is never the case. (NonNull and actually a weakref type)

pub fn upgrade_as_exact<T>(&self) -> PyResult<Option<&T::AsRefTarget>>

where T: PyTypeInfo,

Available on crate feature gil-refs only.

Upgrade the weakref to an exact direct object reference.

It is named upgrade to be inline with rust’s Weak::upgrade. In Python it would be equivalent to PyWeakref_GetObject or calling the weakref.ReferenceType (result of calling weakref.ref).

Example

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

#[pymethods]
impl Foo {
    fn get_data(&self) -> (&str, u32) {
        ("Dave", 10)
    }
}

fn parse_data(reference: Borrowed<'_, '_, PyWeakrefReference>) -> PyResult<String> {
    if let Some(data_src) = reference.upgrade_as_exact::<Foo>()? {
        let data = data_src.borrow();
        let (name, score) = data.get_data();
        Ok(format!("Processing '{}': score = {}", name, score))
    } else {
        Ok("The supplied data reference is nolonger relavent.".to_owned())
    }
}

Python::with_gil(|py| {
    let data = Bound::new(py, Foo{})?;
    let reference = PyWeakrefReference::new_bound(&data)?;

    assert_eq!(
        parse_data(reference.as_borrowed())?,
        "Processing 'Dave': score = 10"
    );

    drop(data);

    assert_eq!(
        parse_data(reference.as_borrowed())?,
        "The supplied data reference is nolonger relavent."
    );

    Ok(())
})

Panics

This function panics is the current object is invalid. If used propperly this is never the case. (NonNull and actually a weakref type)

pub fn upgrade(&self) -> Option<&PyAny>

Available on crate feature gil-refs only.

Upgrade the weakref to a PyAny reference to the target if possible.

It is named upgrade to be inline with rust’s Weak::upgrade. This function returns Some(&'py PyAny) if the reference still exists, otherwise None will be returned.

This function gets the optional target of this weakref.ReferenceType (result of calling weakref.ref). It produces similair results to calling the weakref.ReferenceType or using PyWeakref_GetObject in the C api.

Example

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

fn parse_data(reference: Borrowed<'_, '_, PyWeakrefReference>) -> PyResult<String> {
    if let Some(object) = reference.upgrade() {
        Ok(format!("The object '{}' refered by this reference still exists.", object.getattr("__class__")?.getattr("__qualname__")?))
    } else {
        Ok("The object, which this reference refered to, no longer exists".to_owned())
    }
}

Python::with_gil(|py| {
    let data = Bound::new(py, Foo{})?;
    let reference = PyWeakrefReference::new_bound(&data)?;

    assert_eq!(
        parse_data(reference.as_borrowed())?,
        "The object 'Foo' refered by this reference still exists."
    );

    drop(data);

    assert_eq!(
        parse_data(reference.as_borrowed())?,
        "The object, which this reference refered to, no longer exists"
    );

    Ok(())
})

Panics

This function panics is the current object is invalid. If used propperly this is never the case. (NonNull and actually a weakref type)

pub fn get_object(&self) -> &PyAny

Available on crate feature gil-refs only.

Retrieve to a object pointed to by the weakref.

This function returns &'py PyAny, which is either the object if it still exists, otherwise it will refer to PyNone.

This function gets the optional target of this weakref.ReferenceType (result of calling weakref.ref). It produces similair results to calling the weakref.ReferenceType or using PyWeakref_GetObject in the C api.

Example

use pyo3::prelude::*;
use pyo3::types::PyWeakrefReference;

#[pyclass(weakref)]
struct Foo { /* fields omitted */ }

fn get_class(reference: Borrowed<'_, '_, PyWeakrefReference>) -> PyResult<String> {
    reference
        .get_object()
        .getattr("__class__")?
        .repr()
        .map(|repr| repr.to_string())
}

Python::with_gil(|py| {
    let object = Bound::new(py, Foo{})?;
    let reference = PyWeakrefReference::new_bound(&object)?;

    assert_eq!(
        get_class(reference.as_borrowed())?,
        "<class 'builtins.Foo'>"
    );

    drop(object);

    assert_eq!(get_class(reference.as_borrowed())?, "<class 'NoneType'>");

    Ok(())
})

Panics

This function panics is the current object is invalid. If used propperly this is never the case. (NonNull and actually a weakref type)

Methods from Deref<Target = PyAny>

pub fn is<T: AsPyPointer>(&self, other: &T) -> bool

Available on crate feature gil-refs only.

Returns whether self and other point to the same object. To compare the equality of two objects (the == operator), use eq.

This is equivalent to the Python expression self is other.

pub fn hasattr<N>(&self, attr_name: N) -> PyResult<bool>

where N: IntoPy<Py<PyString>>,

Available on crate feature gil-refs only.

Determines whether this object has the given attribute.

This is equivalent to the Python expression hasattr(self, attr_name).

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern attr_name.

Example: intern!ing the attribute name

#[pyfunction]
fn has_version(sys: &Bound<'_, PyModule>) -> PyResult<bool> {
    sys.hasattr(intern!(sys.py(), "version"))
}

pub fn getattr<N>(&self, attr_name: N) -> PyResult<&PyAny>

where N: IntoPy<Py<PyString>>,

Available on crate feature gil-refs only.

Retrieves an attribute value.

This is equivalent to the Python expression self.attr_name.

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern attr_name.

Example: intern!ing the attribute name

#[pyfunction]
fn version<'py>(sys: &Bound<'py, PyModule>) -> PyResult<Bound<'py, PyAny>> {
    sys.getattr(intern!(sys.py(), "version"))
}

pub fn setattr<N, V>(&self, attr_name: N, value: V) -> PyResult<()>

where N: IntoPy<Py<PyString>>, V: ToPyObject,

Available on crate feature gil-refs only.

Sets an attribute value.

This is equivalent to the Python expression self.attr_name = value.

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern name.

Example: intern!ing the attribute name

#[pyfunction]
fn set_answer(ob: &Bound<'_, PyAny>) -> PyResult<()> {
    ob.setattr(intern!(ob.py(), "answer"), 42)
}

pub fn delattr<N>(&self, attr_name: N) -> PyResult<()>

where N: IntoPy<Py<PyString>>,

Available on crate feature gil-refs only.

Deletes an attribute.

This is equivalent to the Python statement del self.attr_name.

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern attr_name.

pub fn compare<O>(&self, other: O) -> PyResult<Ordering>

where O: ToPyObject,

Available on crate feature gil-refs only.

Returns an Ordering between self and other.

This is equivalent to the following Python code:

if self == other:
    return Equal
elif a < b:
    return Less
elif a > b:
    return Greater
else:
    raise TypeError("PyAny::compare(): All comparisons returned false")

Examples

use pyo3::prelude::*;
use pyo3::types::PyFloat;
use std::cmp::Ordering;

Python::with_gil(|py| -> PyResult<()> {
    let a = PyFloat::new_bound(py, 0_f64);
    let b = PyFloat::new_bound(py, 42_f64);
    assert_eq!(a.compare(b)?, Ordering::Less);
    Ok(())
})?;

It will return PyErr for values that cannot be compared:

use pyo3::prelude::*;
use pyo3::types::{PyFloat, PyString};

Python::with_gil(|py| -> PyResult<()> {
    let a = PyFloat::new_bound(py, 0_f64);
    let b = PyString::new_bound(py, "zero");
    assert!(a.compare(b).is_err());
    Ok(())
})?;

pub fn rich_compare<O>( &self, other: O, compare_op: CompareOp, ) -> PyResult<&PyAny>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether two Python objects obey a given CompareOp.

lt, le, eq, ne, gt and ge are the specialized versions of this function.

Depending on the value of compare_op, this is equivalent to one of the following Python expressions:

compare_op	Python expression
CompareOp::Eq	self == other
CompareOp::Ne	self != other
CompareOp::Lt	self < other
CompareOp::Le	self <= other
CompareOp::Gt	self > other
CompareOp::Ge	self >= other

Examples

use pyo3::class::basic::CompareOp;
use pyo3::prelude::*;
use pyo3::types::PyInt;

Python::with_gil(|py| -> PyResult<()> {
    let a: Bound<'_, PyInt> = 0_u8.into_py(py).into_bound(py).downcast_into()?;
    let b: Bound<'_, PyInt> = 42_u8.into_py(py).into_bound(py).downcast_into()?;
    assert!(a.rich_compare(b, CompareOp::Le)?.is_truthy()?);
    Ok(())
})?;

pub fn lt<O>(&self, other: O) -> PyResult<bool>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether this object is less than another.

This is equivalent to the Python expression self < other.

pub fn le<O>(&self, other: O) -> PyResult<bool>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether this object is less than or equal to another.

This is equivalent to the Python expression self <= other.

pub fn eq<O>(&self, other: O) -> PyResult<bool>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether this object is equal to another.

This is equivalent to the Python expression self == other.

pub fn ne<O>(&self, other: O) -> PyResult<bool>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether this object is not equal to another.

This is equivalent to the Python expression self != other.

pub fn gt<O>(&self, other: O) -> PyResult<bool>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether this object is greater than another.

This is equivalent to the Python expression self > other.

pub fn ge<O>(&self, other: O) -> PyResult<bool>

where O: ToPyObject,

Available on crate feature gil-refs only.

Tests whether this object is greater than or equal to another.

This is equivalent to the Python expression self >= other.

pub fn is_callable(&self) -> bool

Available on crate feature gil-refs only.

Determines whether this object appears callable.

This is equivalent to Python’s callable() function.

Examples

use pyo3::prelude::*;

Python::with_gil(|py| -> PyResult<()> {
    let builtins = PyModule::import_bound(py, "builtins")?;
    let print = builtins.getattr("print")?;
    assert!(print.is_callable());
    Ok(())
})?;

This is equivalent to the Python statement assert callable(print).

Note that unless an API needs to distinguish between callable and non-callable objects, there is no point in checking for callability. Instead, it is better to just do the call and handle potential exceptions.

pub fn call( &self, args: impl IntoPy<Py<PyTuple>>, kwargs: Option<&PyDict>, ) -> PyResult<&PyAny>

Available on crate feature gil-refs only.

Calls the object.

This is equivalent to the Python expression self(*args, **kwargs).

Examples

use pyo3::prelude::*;
use pyo3::types::PyDict;

const CODE: &str = r#"
def function(*args, **kwargs):
    assert args == ("hello",)
    assert kwargs == {"cruel": "world"}
    return "called with args and kwargs"
"#;

Python::with_gil(|py| {
    let module = PyModule::from_code_bound(py, CODE, "", "")?;
    let fun = module.getattr("function")?;
    let args = ("hello",);
    let kwargs = PyDict::new_bound(py);
    kwargs.set_item("cruel", "world")?;
    let result = fun.call(args, Some(&kwargs))?;
    assert_eq!(result.extract::<String>()?, "called with args and kwargs");
    Ok(())
})

pub fn call0(&self) -> PyResult<&PyAny>

Available on crate feature gil-refs only.

Calls the object without arguments.

This is equivalent to the Python expression self().

Examples

use pyo3::prelude::*;

Python::with_gil(|py| -> PyResult<()> {
    let module = PyModule::import_bound(py, "builtins")?;
    let help = module.getattr("help")?;
    help.call0()?;
    Ok(())
})?;

This is equivalent to the Python expression help().

pub fn call1(&self, args: impl IntoPy<Py<PyTuple>>) -> PyResult<&PyAny>

Available on crate feature gil-refs only.

Calls the object with only positional arguments.

This is equivalent to the Python expression self(*args).

Examples

use pyo3::prelude::*;

const CODE: &str = r#"
def function(*args, **kwargs):
    assert args == ("hello",)
    assert kwargs == {}
    return "called with args"
"#;

Python::with_gil(|py| {
    let module = PyModule::from_code_bound(py, CODE, "", "")?;
    let fun = module.getattr("function")?;
    let args = ("hello",);
    let result = fun.call1(args)?;
    assert_eq!(result.extract::<String>()?, "called with args");
    Ok(())
})

pub fn call_method<N, A>( &self, name: N, args: A, kwargs: Option<&PyDict>, ) -> PyResult<&PyAny>

where N: IntoPy<Py<PyString>>, A: IntoPy<Py<PyTuple>>,

Available on crate feature gil-refs only.

Calls a method on the object.

This is equivalent to the Python expression self.name(*args, **kwargs).

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern name.

Examples

use pyo3::prelude::*;
use pyo3::types::PyDict;

const CODE: &str = r#"
class A:
    def method(self, *args, **kwargs):
        assert args == ("hello",)
        assert kwargs == {"cruel": "world"}
        return "called with args and kwargs"
a = A()
"#;

Python::with_gil(|py| {
    let module = PyModule::from_code_bound(py, CODE, "", "")?;
    let instance = module.getattr("a")?;
    let args = ("hello",);
    let kwargs = PyDict::new_bound(py);
    kwargs.set_item("cruel", "world")?;
    let result = instance.call_method("method", args, Some(&kwargs))?;
    assert_eq!(result.extract::<String>()?, "called with args and kwargs");
    Ok(())
})

pub fn call_method0<N>(&self, name: N) -> PyResult<&PyAny>

where N: IntoPy<Py<PyString>>,

Available on crate feature gil-refs only.

Calls a method on the object without arguments.

This is equivalent to the Python expression self.name().

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern name.

Examples

use pyo3::prelude::*;

const CODE: &str = r#"
class A:
    def method(self, *args, **kwargs):
        assert args == ()
        assert kwargs == {}
        return "called with no arguments"
a = A()
"#;

Python::with_gil(|py| {
    let module = PyModule::from_code_bound(py, CODE, "", "")?;
    let instance = module.getattr("a")?;
    let result = instance.call_method0("method")?;
    assert_eq!(result.extract::<String>()?, "called with no arguments");
    Ok(())
})

pub fn call_method1<N, A>(&self, name: N, args: A) -> PyResult<&PyAny>

where N: IntoPy<Py<PyString>>, A: IntoPy<Py<PyTuple>>,

Available on crate feature gil-refs only.

Calls a method on the object with only positional arguments.

This is equivalent to the Python expression self.name(*args).

To avoid repeated temporary allocations of Python strings, the intern! macro can be used to intern name.

Examples

use pyo3::prelude::*;

const CODE: &str = r#"
class A:
    def method(self, *args, **kwargs):
        assert args == ("hello",)
        assert kwargs == {}
        return "called with args"
a = A()
"#;

Python::with_gil(|py| {
    let module = PyModule::from_code_bound(py, CODE, "", "")?;
    let instance = module.getattr("a")?;
    let args = ("hello",);
    let result = instance.call_method1("method", args)?;
    assert_eq!(result.extract::<String>()?, "called with args");
    Ok(())
})

pub fn is_true(&self) -> PyResult<bool>

👎Deprecated since 0.21.0: use .is_truthy() instead

Available on crate feature gil-refs only.

Returns whether the object is considered to be true.

This is equivalent to the Python expression bool(self).

pub fn is_truthy(&self) -> PyResult<bool>

Available on crate feature gil-refs only.

Returns whether the object is considered to be true.

This applies truth value testing equivalent to the Python expression bool(self).

pub fn is_none(&self) -> bool

Available on crate feature gil-refs only.

Returns whether the object is considered to be None.

This is equivalent to the Python expression self is None.

pub fn is_ellipsis(&self) -> bool

👎Deprecated since 0.20.0: use .is(py.Ellipsis()) instead

Available on crate feature gil-refs only.

Returns whether the object is Ellipsis, e.g. ....

This is equivalent to the Python expression self is ....

pub fn is_empty(&self) -> PyResult<bool>

Available on crate feature gil-refs only.

Returns true if the sequence or mapping has a length of 0.

This is equivalent to the Python expression len(self) == 0.

pub fn get_item<K>(&self, key: K) -> PyResult<&PyAny>

where K: ToPyObject,

Available on crate feature gil-refs only.

Gets an item from the collection.

This is equivalent to the Python expression self[key].

pub fn set_item<K, V>(&self, key: K, value: V) -> PyResult<()>

where K: ToPyObject, V: ToPyObject,

Available on crate feature gil-refs only.

Sets a collection item value.

This is equivalent to the Python expression self[key] = value.

pub fn del_item<K>(&self, key: K) -> PyResult<()>

where K: ToPyObject,

Available on crate feature gil-refs only.

Deletes an item from the collection.

This is equivalent to the Python expression del self[key].

pub fn iter(&self) -> PyResult<&PyIterator>

Available on crate feature gil-refs only.

Takes an object and returns an iterator for it.

This is typically a new iterator but if the argument is an iterator, this returns itself.

pub fn get_type(&self) -> &PyType

Available on crate feature gil-refs only.

Returns the Python type object for this object’s type.

pub fn get_type_ptr(&self) -> *mut PyTypeObject

Available on crate feature gil-refs only.

Returns the Python type pointer for this object.

pub fn downcast<T>(&self) -> Result<&T, PyDowncastError<'_>>

where T: PyTypeCheck<AsRefTarget = T>,

Available on crate feature gil-refs only.

Downcast this PyAny to a concrete Python type or pyclass.

Note that you can often avoid downcasting yourself by just specifying the desired type in function or method signatures. However, manual downcasting is sometimes necessary.

For extracting a Rust-only type, see PyAny::extract.

Example: Downcasting to a specific Python object

use pyo3::prelude::*;
use pyo3::types::{PyDict, PyList};

Python::with_gil(|py| {
    let dict = PyDict::new_bound(py);
    assert!(dict.is_instance_of::<PyAny>());
    let any = dict.as_any();

    assert!(any.downcast::<PyDict>().is_ok());
    assert!(any.downcast::<PyList>().is_err());
});

Example: Getting a reference to a pyclass

This is useful if you want to mutate a PyObject that might actually be a pyclass.

use pyo3::prelude::*;

#[pyclass]
struct Class {
    i: i32,
}

Python::with_gil(|py| {
    let class = Py::new(py, Class { i: 0 }).unwrap().into_bound(py).into_any();

    let class_bound: &Bound<'_, Class> = class.downcast()?;

    class_bound.borrow_mut().i += 1;

    // Alternatively you can get a `PyRefMut` directly
    let class_ref: PyRefMut<'_, Class> = class.extract()?;
    assert_eq!(class_ref.i, 1);
    Ok(())
})

pub fn downcast_exact<T>(&self) -> Result<&T, PyDowncastError<'_>>

where T: PyTypeInfo<AsRefTarget = T>,

Available on crate feature gil-refs only.

Downcast this PyAny to a concrete Python type or pyclass (but not a subclass of it).

It is almost always better to use PyAny::downcast because it accounts for Python subtyping. Use this method only when you do not want to allow subtypes.

The advantage of this method over PyAny::downcast is that it is faster. The implementation of downcast_exact uses the equivalent of the Python expression type(self) is T, whereas downcast uses isinstance(self, T).

For extracting a Rust-only type, see PyAny::extract.

Example: Downcasting to a specific Python object but not a subtype

use pyo3::prelude::*;
use pyo3::types::{PyBool, PyLong};

Python::with_gil(|py| {
    let b = PyBool::new_bound(py, true);
    assert!(b.is_instance_of::<PyBool>());
    let any: &Bound<'_, PyAny> = b.as_any();

    // `bool` is a subtype of `int`, so `downcast` will accept a `bool` as an `int`
    // but `downcast_exact` will not.
    assert!(any.downcast::<PyLong>().is_ok());
    assert!(any.downcast_exact::<PyLong>().is_err());

    assert!(any.downcast_exact::<PyBool>().is_ok());
});

pub unsafe fn downcast_unchecked<T>(&self) -> &T

where T: HasPyGilRef<AsRefTarget = T>,

Available on crate feature gil-refs only.

Converts this PyAny to a concrete Python type without checking validity.

Safety

Callers must ensure that the type is valid or risk type confusion.

pub fn extract<'py, D>(&'py self) -> PyResult<D>

where D: FromPyObjectBound<'py, 'py>,

Available on crate feature gil-refs only.

Extracts some type from the Python object.

This is a wrapper function around FromPyObject::extract().

pub fn get_refcnt(&self) -> isize

Available on crate feature gil-refs only.

Returns the reference count for the Python object.

pub fn repr(&self) -> PyResult<&PyString>

Available on crate feature gil-refs only.

Computes the “repr” representation of self.

This is equivalent to the Python expression repr(self).

pub fn str(&self) -> PyResult<&PyString>

Available on crate feature gil-refs only.

Computes the “str” representation of self.

This is equivalent to the Python expression str(self).

pub fn hash(&self) -> PyResult<isize>

Available on crate feature gil-refs only.

Retrieves the hash code of self.

This is equivalent to the Python expression hash(self).

pub fn len(&self) -> PyResult<usize>

Available on crate feature gil-refs only.

Returns the length of the sequence or mapping.

This is equivalent to the Python expression len(self).

pub fn dir(&self) -> PyResult<&PyList>

Available on crate feature gil-refs only.

Returns the list of attributes of this object.

This is equivalent to the Python expression dir(self).

pub fn is_instance(&self, ty: &PyAny) -> PyResult<bool>

Available on crate feature gil-refs only.

Checks whether this object is an instance of type ty.

This is equivalent to the Python expression isinstance(self, ty).

pub fn is_exact_instance(&self, ty: &PyAny) -> bool

Available on crate feature gil-refs only.

Checks whether this object is an instance of exactly type ty (not a subclass).

This is equivalent to the Python expression type(self) is ty.

pub fn is_instance_of<T: PyTypeInfo>(&self) -> bool

Available on crate feature gil-refs only.

Checks whether this object is an instance of type T.

This is equivalent to the Python expression isinstance(self, T), if the type T is known at compile time.

pub fn is_exact_instance_of<T: PyTypeInfo>(&self) -> bool

Available on crate feature gil-refs only.

Checks whether this object is an instance of exactly type T.

This is equivalent to the Python expression type(self) is T, if the type T is known at compile time.

pub fn contains<V>(&self, value: V) -> PyResult<bool>

where V: ToPyObject,

Available on crate feature gil-refs only.

Determines if self contains value.

This is equivalent to the Python expression value in self.

pub fn py(&self) -> Python<'_>

Available on crate feature gil-refs only.

Returns a GIL marker constrained to the lifetime of this type.

pub fn as_ptr(&self) -> *mut PyObject

Available on crate feature gil-refs only.

Returns the raw FFI pointer represented by self.

Safety

Callers are responsible for ensuring that the pointer does not outlive self.

The reference is borrowed; callers should not decrease the reference count when they are finished with the pointer.

pub fn into_ptr(&self) -> *mut PyObject

Available on crate feature gil-refs only.

Returns an owned raw FFI pointer represented by self.

Safety

The reference is owned; when finished the caller should either transfer ownership of the pointer or decrease the reference count (e.g. with pyo3::ffi::Py_DecRef).

pub fn py_super(&self) -> PyResult<&PySuper>

Available on crate feature gil-refs and neither PyPy nor GraalPy only.

Return a proxy object that delegates method calls to a parent or sibling class of type.

This is equivalent to the Python expression super()

Trait Implementations

impl AsPyPointer for PyWeakrefReference

fn as_ptr(&self) -> *mut PyObject

Gets the underlying FFI pointer, returns a borrowed pointer.

impl AsRef<PyAny> for PyWeakrefReference

fn as_ref(&self) -> &PyAny

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

impl Debug for PyWeakrefReference

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Deref for PyWeakrefReference

type Target = PyAny

The resulting type after dereferencing.

fn deref(&self) -> &PyAny

Dereferences the value.

impl Display for PyWeakrefReference

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> From<&'a PyWeakrefReference> for &'a PyAny

fn from(ob: &'a PyWeakrefReference) -> Self

Converts to this type from the input type.

impl From<&PyWeakrefReference> for Py<PyWeakrefReference>

fn from(other: &PyWeakrefReference) -> Self

Converts to this type from the input type.

impl<'py> FromPyObject<'py> for &'py PyWeakrefReference

fn extract_bound(obj: &Bound<'py, PyAny>) -> PyResult<Self>

Extracts Self from the bound smart pointer obj.

fn extract(ob: &'py PyAny) -> PyResult<Self>

Available on crate feature gil-refs only.

Extracts Self from the source GIL Ref obj.

fn type_input() -> TypeInfo

Available on crate feature experimental-inspect only.

Extracts the type hint information for this type when it appears as an argument.

impl IntoPy<Py<PyWeakrefReference>> for &PyWeakrefReference

fn into_py(self, py: Python<'_>) -> Py<PyWeakrefReference>

Performs the conversion.

fn type_output() -> TypeInfo

Available on crate feature experimental-inspect only.

Extracts the type hint information for this type when it appears as a return value.

impl PyNativeType for PyWeakrefReference

type AsRefSource = PyWeakrefReference

Available on crate feature gil-refs only.

The form of this which is stored inside a Py<T> smart pointer.

fn as_borrowed(&self) -> Borrowed<'_, '_, Self::AsRefSource>

Available on crate feature gil-refs only.

Cast &self to a Borrowed smart pointer.

fn py(&self) -> Python<'_>

Available on crate feature gil-refs only.

Returns a GIL marker constrained to the lifetime of this type.

unsafe fn unchecked_downcast(obj: &PyAny) -> &Self

Available on crate feature gil-refs only.

Cast &PyAny to &Self without no type checking.

impl PyTypeInfo for PyWeakrefReference

const NAME: &'static str = "PyWeakrefReference"

Available on crate feature gil-refs only.

Class name.

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

Available on crate feature gil-refs only.

Module name, if any.

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

Available on crate feature gil-refs only.

Returns the PyTypeObject instance for this type.

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

Available on crate feature gil-refs only.

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

fn type_object(py: Python<'_>) -> &PyType

👎Deprecated since 0.21.0: PyTypeInfo::type_object will be replaced by PyTypeInfo::type_object_bound in a future PyO3 version

Available on crate feature gil-refs only.

Returns the safe abstraction over the type object.

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

Available on crate feature gil-refs only.

Returns the safe abstraction over the type object.

fn is_type_of(object: &PyAny) -> bool

👎Deprecated since 0.21.0: PyTypeInfo::is_type_of will be replaced by PyTypeInfo::is_type_of_bound in a future PyO3 version

Available on crate feature gil-refs only.

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

fn is_exact_type_of(object: &PyAny) -> bool

👎Deprecated since 0.21.0: PyTypeInfo::is_exact_type_of will be replaced by PyTypeInfo::is_exact_type_of_bound in a future PyO3 version

Available on crate feature gil-refs only.

Checks if object is an instance of this type.

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

Available on crate feature gil-refs only.

Checks if object is an instance of this type.

impl ToPyObject for PyWeakrefReference

fn to_object(&self, py: Python<'_>) -> PyObject

Converts self into a Python object.

impl DerefToPyAny for PyWeakrefReference

impl PyLayout<PyWeakrefReference> for PyWeakReference

impl PySizedLayout<PyWeakrefReference> for PyWeakReference