Struct numpy::PyArrayDescr
source · pub struct PyArrayDescr(/* private fields */);
Expand description
Binding of numpy.dtype
.
§Example
use numpy::{dtype_bound, get_array_module, PyArrayDescr, PyArrayDescrMethods};
use numpy::pyo3::{types::{IntoPyDict, PyAnyMethods}, Python};
Python::with_gil(|py| {
let locals = [("np", get_array_module(py).unwrap())].into_py_dict_bound(py);
let dt = py
.eval_bound("np.array([1, 2, 3.0]).dtype", Some(&locals), None)
.unwrap()
.downcast_into::<PyArrayDescr>()
.unwrap();
assert!(dt.is_equiv_to(&dtype_bound::<f64>(py)));
});
Implementations§
source§impl PyArrayDescr
impl PyArrayDescr
sourcepub fn new<'py, T: ToPyObject + ?Sized>(
py: Python<'py>,
ob: &T
) -> PyResult<&'py Self>
👎Deprecated since 0.21.0: This will be replace by new_bound
in the future.
pub fn new<'py, T: ToPyObject + ?Sized>( py: Python<'py>, ob: &T ) -> PyResult<&'py Self>
new_bound
in the future.Creates a new type descriptor (“dtype”) object from an arbitrary object.
Equivalent to invoking the constructor of numpy.dtype
.
sourcepub fn new_bound<'py, T: ToPyObject + ?Sized>(
py: Python<'py>,
ob: &T
) -> PyResult<Bound<'py, Self>>
pub fn new_bound<'py, T: ToPyObject + ?Sized>( py: Python<'py>, ob: &T ) -> PyResult<Bound<'py, Self>>
Creates a new type descriptor (“dtype”) object from an arbitrary object.
Equivalent to invoking the constructor of numpy.dtype
.
sourcepub fn as_dtype_ptr(&self) -> *mut PyArray_Descr
pub fn as_dtype_ptr(&self) -> *mut PyArray_Descr
Returns self
as *mut PyArray_Descr
.
sourcepub fn into_dtype_ptr(&self) -> *mut PyArray_Descr
pub fn into_dtype_ptr(&self) -> *mut PyArray_Descr
Returns self
as *mut PyArray_Descr
while increasing the reference count.
Useful in cases where the descriptor is stolen by the API.
sourcepub fn object<'py>(py: Python<'py>) -> &'py Self
👎Deprecated since 0.21.0: This will be replaced by object_bound
in the future.
pub fn object<'py>(py: Python<'py>) -> &'py Self
object_bound
in the future.Shortcut for creating a type descriptor of object
type.
sourcepub fn object_bound(py: Python<'_>) -> Bound<'_, Self>
pub fn object_bound(py: Python<'_>) -> Bound<'_, Self>
Shortcut for creating a type descriptor of object
type.
sourcepub fn of<'py, T: Element>(py: Python<'py>) -> &'py Self
👎Deprecated since 0.21.0: This will be replaced by of_bound
in the future.
pub fn of<'py, T: Element>(py: Python<'py>) -> &'py Self
of_bound
in the future.Returns the type descriptor for a registered type.
sourcepub fn of_bound<'py, T: Element>(py: Python<'py>) -> Bound<'py, Self>
pub fn of_bound<'py, T: Element>(py: Python<'py>) -> Bound<'py, Self>
Returns the type descriptor for a registered type.
sourcepub fn is_equiv_to(&self, other: &Self) -> bool
pub fn is_equiv_to(&self, other: &Self) -> bool
Returns true if two type descriptors are equivalent.
sourcepub fn typeobj(&self) -> &PyType
pub fn typeobj(&self) -> &PyType
Returns the array scalar corresponding to this type descriptor.
Equivalent to numpy.dtype.type
.
sourcepub fn num(&self) -> c_int
pub fn num(&self) -> c_int
Returns a unique number for each of the 21 different built-in enumerated types.
These are roughly ordered from least-to-most precision.
Equivalent to numpy.dtype.num
.
sourcepub fn itemsize(&self) -> usize
pub fn itemsize(&self) -> usize
Returns the element size of this type descriptor.
Equivalent to [numpy.dtype.itemsize
][dtype-itemsize].
sourcepub fn alignment(&self) -> usize
pub fn alignment(&self) -> usize
Returns the required alignment (bytes) of this type descriptor according to the compiler.
Equivalent to numpy.dtype.alignment
.
sourcepub fn byteorder(&self) -> u8
pub fn byteorder(&self) -> u8
Returns an ASCII character indicating the byte-order of this type descriptor object.
All built-in data-type objects have byteorder either =
or |
.
Equivalent to numpy.dtype.byteorder
.
sourcepub fn char(&self) -> u8
pub fn char(&self) -> u8
Returns a unique ASCII character for each of the 21 different built-in types.
Note that structured data types are categorized as V
(void).
Equivalent to numpy.dtype.char
.
sourcepub fn kind(&self) -> u8
pub fn kind(&self) -> u8
Returns an ASCII character (one of biufcmMOSUV
) identifying the general kind of data.
Note that structured data types are categorized as V
(void).
Equivalent to numpy.dtype.kind
.
sourcepub fn flags(&self) -> c_char
pub fn flags(&self) -> c_char
Returns bit-flags describing how this type descriptor is to be interpreted.
Equivalent to numpy.dtype.flags
.
sourcepub fn ndim(&self) -> usize
pub fn ndim(&self) -> usize
Returns the number of dimensions if this type descriptor represents a sub-array, and zero otherwise.
Equivalent to numpy.dtype.ndim
.
sourcepub fn base(&self) -> &PyArrayDescr
pub fn base(&self) -> &PyArrayDescr
Returns the type descriptor for the base element of subarrays, regardless of their dimension or shape.
If the dtype is not a subarray, returns self.
Equivalent to numpy.dtype.base
.
sourcepub fn shape(&self) -> Vec<usize>
pub fn shape(&self) -> Vec<usize>
Returns the shape of the sub-array.
If the dtype is not a sub-array, an empty vector is returned.
Equivalent to numpy.dtype.shape
.
sourcepub fn has_object(&self) -> bool
pub fn has_object(&self) -> bool
Returns true if the type descriptor contains any reference-counted objects in any fields or sub-dtypes.
Equivalent to numpy.dtype.hasobject
.
sourcepub fn is_aligned_struct(&self) -> bool
pub fn is_aligned_struct(&self) -> bool
Returns true if the type descriptor is a struct which maintains field alignment.
This flag is sticky, so when combining multiple structs together, it is preserved and produces new dtypes which are also aligned.
Equivalent to numpy.dtype.isalignedstruct
.
sourcepub fn has_subarray(&self) -> bool
pub fn has_subarray(&self) -> bool
Returns true if the type descriptor is a sub-array.
sourcepub fn has_fields(&self) -> bool
pub fn has_fields(&self) -> bool
Returns true if the type descriptor is a structured type.
sourcepub fn is_native_byteorder(&self) -> Option<bool>
pub fn is_native_byteorder(&self) -> Option<bool>
Returns true if type descriptor byteorder is native, or None
if not applicable.
sourcepub fn names(&self) -> Option<Vec<String>>
pub fn names(&self) -> Option<Vec<String>>
Returns an ordered list of field names, or None
if there are no fields.
The names are ordered according to increasing byte offset.
Equivalent to numpy.dtype.names
.
sourcepub fn get_field(&self, name: &str) -> PyResult<(&PyArrayDescr, usize)>
pub fn get_field(&self, name: &str) -> PyResult<(&PyArrayDescr, usize)>
Returns the type descriptor and offset of the field with the given name.
This method will return an error if this type descriptor is not structured, or if it does not contain a field with a given name.
The list of all names can be found via PyArrayDescr::names
.
Equivalent to retrieving a single item from numpy.dtype.fields
.
Methods from Deref<Target = PyAny>§
sourcepub fn is<T>(&self, other: &T) -> boolwhere
T: AsPyPointer,
pub fn is<T>(&self, other: &T) -> boolwhere
T: AsPyPointer,
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
.
sourcepub fn hasattr<N>(&self, attr_name: N) -> Result<bool, PyErr>
pub fn hasattr<N>(&self, attr_name: N) -> Result<bool, PyErr>
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"))
}
sourcepub fn getattr<N>(&self, attr_name: N) -> Result<&PyAny, PyErr>
pub fn getattr<N>(&self, attr_name: N) -> Result<&PyAny, PyErr>
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"))
}
sourcepub fn setattr<N, V>(&self, attr_name: N, value: V) -> Result<(), PyErr>
pub fn setattr<N, V>(&self, attr_name: N, value: V) -> Result<(), PyErr>
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)
}
sourcepub fn delattr<N>(&self, attr_name: N) -> Result<(), PyErr>
pub fn delattr<N>(&self, attr_name: N) -> Result<(), PyErr>
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
.
sourcepub fn compare<O>(&self, other: O) -> Result<Ordering, PyErr>where
O: ToPyObject,
pub fn compare<O>(&self, other: O) -> Result<Ordering, PyErr>where
O: ToPyObject,
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(())
})?;
sourcepub fn rich_compare<O>(
&self,
other: O,
compare_op: CompareOp
) -> Result<&PyAny, PyErr>where
O: ToPyObject,
pub fn rich_compare<O>(
&self,
other: O,
compare_op: CompareOp
) -> Result<&PyAny, PyErr>where
O: ToPyObject,
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(())
})?;
sourcepub fn lt<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
pub fn lt<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
Tests whether this object is less than another.
This is equivalent to the Python expression self < other
.
sourcepub fn le<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
pub fn le<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
Tests whether this object is less than or equal to another.
This is equivalent to the Python expression self <= other
.
sourcepub fn eq<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
pub fn eq<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
Tests whether this object is equal to another.
This is equivalent to the Python expression self == other
.
sourcepub fn ne<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
pub fn ne<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
Tests whether this object is not equal to another.
This is equivalent to the Python expression self != other
.
sourcepub fn gt<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
pub fn gt<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
Tests whether this object is greater than another.
This is equivalent to the Python expression self > other
.
sourcepub fn ge<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
pub fn ge<O>(&self, other: O) -> Result<bool, PyErr>where
O: ToPyObject,
Tests whether this object is greater than or equal to another.
This is equivalent to the Python expression self >= other
.
sourcepub fn is_callable(&self) -> bool
pub fn is_callable(&self) -> bool
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.
sourcepub fn call(
&self,
args: impl IntoPy<Py<PyTuple>>,
kwargs: Option<&PyDict>
) -> Result<&PyAny, PyErr>
pub fn call( &self, args: impl IntoPy<Py<PyTuple>>, kwargs: Option<&PyDict> ) -> Result<&PyAny, PyErr>
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(())
})
sourcepub fn call0(&self) -> Result<&PyAny, PyErr>
pub fn call0(&self) -> Result<&PyAny, PyErr>
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()
.
sourcepub fn call1(&self, args: impl IntoPy<Py<PyTuple>>) -> Result<&PyAny, PyErr>
pub fn call1(&self, args: impl IntoPy<Py<PyTuple>>) -> Result<&PyAny, PyErr>
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(())
})
sourcepub fn call_method<N, A>(
&self,
name: N,
args: A,
kwargs: Option<&PyDict>
) -> Result<&PyAny, PyErr>
pub fn call_method<N, A>( &self, name: N, args: A, kwargs: Option<&PyDict> ) -> Result<&PyAny, PyErr>
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(())
})
sourcepub fn call_method0<N>(&self, name: N) -> Result<&PyAny, PyErr>
pub fn call_method0<N>(&self, name: N) -> Result<&PyAny, PyErr>
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(())
})
sourcepub fn call_method1<N, A>(&self, name: N, args: A) -> Result<&PyAny, PyErr>
pub fn call_method1<N, A>(&self, name: N, args: A) -> Result<&PyAny, PyErr>
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(())
})
sourcepub fn is_true(&self) -> Result<bool, PyErr>
👎Deprecated since 0.21.0: use .is_truthy()
instead
pub fn is_true(&self) -> Result<bool, PyErr>
.is_truthy()
insteadReturns whether the object is considered to be true.
This is equivalent to the Python expression bool(self)
.
sourcepub fn is_truthy(&self) -> Result<bool, PyErr>
pub fn is_truthy(&self) -> Result<bool, PyErr>
Returns whether the object is considered to be true.
This applies truth value testing equivalent to the Python expression bool(self)
.
sourcepub fn is_none(&self) -> bool
pub fn is_none(&self) -> bool
Returns whether the object is considered to be None.
This is equivalent to the Python expression self is None
.
sourcepub fn is_ellipsis(&self) -> bool
👎Deprecated since 0.20.0: use .is(py.Ellipsis())
instead
pub fn is_ellipsis(&self) -> bool
.is(py.Ellipsis())
insteadReturns whether the object is Ellipsis, e.g. ...
.
This is equivalent to the Python expression self is ...
.
sourcepub fn is_empty(&self) -> Result<bool, PyErr>
pub fn is_empty(&self) -> Result<bool, PyErr>
Returns true if the sequence or mapping has a length of 0.
This is equivalent to the Python expression len(self) == 0
.
sourcepub fn get_item<K>(&self, key: K) -> Result<&PyAny, PyErr>where
K: ToPyObject,
pub fn get_item<K>(&self, key: K) -> Result<&PyAny, PyErr>where
K: ToPyObject,
Gets an item from the collection.
This is equivalent to the Python expression self[key]
.
sourcepub fn set_item<K, V>(&self, key: K, value: V) -> Result<(), PyErr>where
K: ToPyObject,
V: ToPyObject,
pub fn set_item<K, V>(&self, key: K, value: V) -> Result<(), PyErr>where
K: ToPyObject,
V: ToPyObject,
Sets a collection item value.
This is equivalent to the Python expression self[key] = value
.
sourcepub fn del_item<K>(&self, key: K) -> Result<(), PyErr>where
K: ToPyObject,
pub fn del_item<K>(&self, key: K) -> Result<(), PyErr>where
K: ToPyObject,
Deletes an item from the collection.
This is equivalent to the Python expression del self[key]
.
sourcepub fn iter(&self) -> Result<&PyIterator, PyErr>
pub fn iter(&self) -> Result<&PyIterator, PyErr>
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.
sourcepub fn get_type_ptr(&self) -> *mut PyTypeObject
pub fn get_type_ptr(&self) -> *mut PyTypeObject
Returns the Python type pointer for this object.
sourcepub fn downcast<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeCheck<AsRefTarget = T>,
pub fn downcast<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeCheck<AsRefTarget = T>,
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(())
})
sourcepub fn downcast_exact<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeInfo<AsRefTarget = T>,
pub fn downcast_exact<T>(&self) -> Result<&T, PyDowncastError<'_>>where
T: PyTypeInfo<AsRefTarget = T>,
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());
});
sourcepub unsafe fn downcast_unchecked<T>(&self) -> &Twhere
T: HasPyGilRef<AsRefTarget = T>,
pub unsafe fn downcast_unchecked<T>(&self) -> &Twhere
T: HasPyGilRef<AsRefTarget = T>,
Converts this PyAny
to a concrete Python type without checking validity.
§Safety
Callers must ensure that the type is valid or risk type confusion.
sourcepub fn extract<'py, D>(&'py self) -> Result<D, PyErr>where
D: FromPyObjectBound<'py, 'py>,
pub fn extract<'py, D>(&'py self) -> Result<D, PyErr>where
D: FromPyObjectBound<'py, 'py>,
Extracts some type from the Python object.
This is a wrapper function around
FromPyObject::extract()
.
sourcepub fn get_refcnt(&self) -> isize
pub fn get_refcnt(&self) -> isize
Returns the reference count for the Python object.
sourcepub fn repr(&self) -> Result<&PyString, PyErr>
pub fn repr(&self) -> Result<&PyString, PyErr>
Computes the “repr” representation of self.
This is equivalent to the Python expression repr(self)
.
sourcepub fn str(&self) -> Result<&PyString, PyErr>
pub fn str(&self) -> Result<&PyString, PyErr>
Computes the “str” representation of self.
This is equivalent to the Python expression str(self)
.
sourcepub fn hash(&self) -> Result<isize, PyErr>
pub fn hash(&self) -> Result<isize, PyErr>
Retrieves the hash code of self.
This is equivalent to the Python expression hash(self)
.
sourcepub fn len(&self) -> Result<usize, PyErr>
pub fn len(&self) -> Result<usize, PyErr>
Returns the length of the sequence or mapping.
This is equivalent to the Python expression len(self)
.
sourcepub fn dir(&self) -> &PyList
pub fn dir(&self) -> &PyList
Returns the list of attributes of this object.
This is equivalent to the Python expression dir(self)
.
sourcepub fn is_instance(&self, ty: &PyAny) -> Result<bool, PyErr>
pub fn is_instance(&self, ty: &PyAny) -> Result<bool, PyErr>
Checks whether this object is an instance of type ty
.
This is equivalent to the Python expression isinstance(self, ty)
.
sourcepub fn is_exact_instance(&self, ty: &PyAny) -> bool
pub fn is_exact_instance(&self, ty: &PyAny) -> bool
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
.
sourcepub fn is_instance_of<T>(&self) -> boolwhere
T: PyTypeInfo,
pub fn is_instance_of<T>(&self) -> boolwhere
T: PyTypeInfo,
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.
sourcepub fn is_exact_instance_of<T>(&self) -> boolwhere
T: PyTypeInfo,
pub fn is_exact_instance_of<T>(&self) -> boolwhere
T: PyTypeInfo,
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.
sourcepub fn contains<V>(&self, value: V) -> Result<bool, PyErr>where
V: ToPyObject,
pub fn contains<V>(&self, value: V) -> Result<bool, PyErr>where
V: ToPyObject,
Determines if self contains value
.
This is equivalent to the Python expression value in self
.
sourcepub fn as_ptr(&self) -> *mut PyObject
pub fn as_ptr(&self) -> *mut PyObject
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.
Trait Implementations§
source§impl AsPyPointer for PyArrayDescr
impl AsPyPointer for PyArrayDescr
source§impl AsRef<PyAny> for PyArrayDescr
impl AsRef<PyAny> for PyArrayDescr
source§impl Debug for PyArrayDescr
impl Debug for PyArrayDescr
source§impl Deref for PyArrayDescr
impl Deref for PyArrayDescr
source§impl Display for PyArrayDescr
impl Display for PyArrayDescr
source§impl<'a> From<&'a PyArrayDescr> for &'a PyAny
impl<'a> From<&'a PyArrayDescr> for &'a PyAny
source§fn from(ob: &'a PyArrayDescr) -> Self
fn from(ob: &'a PyArrayDescr) -> Self
source§impl From<&PyArrayDescr> for Py<PyArrayDescr>
impl From<&PyArrayDescr> for Py<PyArrayDescr>
source§fn from(other: &PyArrayDescr) -> Self
fn from(other: &PyArrayDescr) -> Self
source§impl<'py> FromPyObject<'py> for &'py PyArrayDescr
impl<'py> FromPyObject<'py> for &'py PyArrayDescr
source§impl IntoPy<Py<PyArrayDescr>> for &PyArrayDescr
impl IntoPy<Py<PyArrayDescr>> for &PyArrayDescr
source§impl PyNativeType for PyArrayDescr
impl PyNativeType for PyArrayDescr
§type AsRefSource = PyArrayDescr
type AsRefSource = PyArrayDescr
Py<T>
smart pointer.source§fn as_borrowed(&self) -> Borrowed<'_, '_, Self::AsRefSource>
fn as_borrowed(&self) -> Borrowed<'_, '_, Self::AsRefSource>
source§impl PyTypeInfo for PyArrayDescr
impl PyTypeInfo for PyArrayDescr
source§fn type_object_raw<'py>(py: Python<'py>) -> *mut PyTypeObject
fn type_object_raw<'py>(py: Python<'py>) -> *mut PyTypeObject
source§fn is_type_of(ob: &PyAny) -> bool
fn is_type_of(ob: &PyAny) -> bool
PyTypeInfo::is_type_of
will be replaced by PyTypeInfo::is_type_of_bound
in a future PyO3 versionobject
is an instance of this type or a subclass of this type.source§fn type_object(py: Python<'_>) -> &PyType
fn type_object(py: Python<'_>) -> &PyType
PyTypeInfo::type_object
will be replaced by PyTypeInfo::type_object_bound
in a future PyO3 versionsource§fn type_object_bound(py: Python<'_>) -> Bound<'_, PyType>
fn type_object_bound(py: Python<'_>) -> Bound<'_, PyType>
source§fn is_type_of_bound(object: &Bound<'_, PyAny>) -> bool
fn is_type_of_bound(object: &Bound<'_, PyAny>) -> bool
object
is an instance of this type or a subclass of this type.source§fn is_exact_type_of(object: &PyAny) -> bool
fn is_exact_type_of(object: &PyAny) -> bool
PyTypeInfo::is_exact_type_of
will be replaced by PyTypeInfo::is_exact_type_of_bound
in a future PyO3 versionobject
is an instance of this type.source§impl ToPyObject for PyArrayDescr
impl ToPyObject for PyArrayDescr
impl DerefToPyAny for PyArrayDescr
Auto Trait Implementations§
impl !Freeze for PyArrayDescr
impl !RefUnwindSafe for PyArrayDescr
impl !Send for PyArrayDescr
impl !Sync for PyArrayDescr
impl Unpin for PyArrayDescr
impl UnwindSafe for PyArrayDescr
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<'p, T> FromPyPointer<'p> for Twhere
T: 'p + PyNativeType,
impl<'p, T> FromPyPointer<'p> for Twhere
T: 'p + PyNativeType,
source§unsafe fn from_owned_ptr_or_opt(
py: Python<'p>,
ptr: *mut PyObject
) -> Option<&'p T>
unsafe fn from_owned_ptr_or_opt( py: Python<'p>, ptr: *mut PyObject ) -> Option<&'p T>
Py::from_owned_ptr_or_opt(py, ptr)
or Bound::from_owned_ptr_or_opt(py, ptr)
insteadPyObject
. Read moresource§unsafe fn from_borrowed_ptr_or_opt(
_py: Python<'p>,
ptr: *mut PyObject
) -> Option<&'p T>
unsafe fn from_borrowed_ptr_or_opt( _py: Python<'p>, ptr: *mut PyObject ) -> Option<&'p T>
Py::from_borrowed_ptr_or_opt(py, ptr)
or Bound::from_borrowed_ptr_or_opt(py, ptr)
insteadPyObject
. Read moresource§unsafe fn from_owned_ptr_or_panic(
py: Python<'p>,
ptr: *mut PyObject
) -> &'p Self
unsafe fn from_owned_ptr_or_panic( py: Python<'p>, ptr: *mut PyObject ) -> &'p Self
Py::from_owned_ptr(py, ptr)
or Bound::from_owned_ptr(py, ptr)
insteadPyObject
or panic. Read moresource§unsafe fn from_owned_ptr(py: Python<'p>, ptr: *mut PyObject) -> &'p Self
unsafe fn from_owned_ptr(py: Python<'p>, ptr: *mut PyObject) -> &'p Self
Py::from_owned_ptr(py, ptr)
or Bound::from_owned_ptr(py, ptr)
insteadPyObject
or panic. Read moresource§unsafe fn from_owned_ptr_or_err(
py: Python<'p>,
ptr: *mut PyObject
) -> Result<&'p Self, PyErr>
unsafe fn from_owned_ptr_or_err( py: Python<'p>, ptr: *mut PyObject ) -> Result<&'p Self, PyErr>
Py::from_owned_ptr_or_err(py, ptr)
or Bound::from_owned_ptr_or_err(py, ptr)
insteadPyObject
. Read moresource§unsafe fn from_borrowed_ptr_or_panic(
py: Python<'p>,
ptr: *mut PyObject
) -> &'p Self
unsafe fn from_borrowed_ptr_or_panic( py: Python<'p>, ptr: *mut PyObject ) -> &'p Self
Py::from_borrowed_ptr(py, ptr)
or Bound::from_borrowed_ptr(py, ptr)
insteadPyObject
. Read moresource§impl<T> HasPyGilRef for Twhere
T: PyNativeType,
impl<T> HasPyGilRef for Twhere
T: PyNativeType,
§type AsRefTarget = T
type AsRefTarget = T
source§impl<'v, T> PyTryFrom<'v> for Twhere
T: PyTypeInfo<AsRefTarget = T> + PyNativeType,
impl<'v, T> PyTryFrom<'v> for Twhere
T: PyTypeInfo<AsRefTarget = T> + PyNativeType,
source§fn try_from<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
fn try_from<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
value.downcast::<T>()
instead of T::try_from(value)
source§fn try_from_exact<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
fn try_from_exact<V>(value: V) -> Result<&'v T, PyDowncastError<'v>>
value.downcast_exact::<T>()
instead of T::try_from_exact(value)
source§unsafe fn try_from_unchecked<V>(value: V) -> &'v T
unsafe fn try_from_unchecked<V>(value: V) -> &'v T
value.downcast_unchecked::<T>()
instead of T::try_from_unchecked(value)
source§impl<T> PyTypeCheck for Twhere
T: PyTypeInfo,
impl<T> PyTypeCheck for Twhere
T: PyTypeInfo,
source§impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
impl<SS, SP> SupersetOf<SS> for SPwhere
SS: SubsetOf<SP>,
source§fn to_subset(&self) -> Option<SS>
fn to_subset(&self) -> Option<SS>
self
from the equivalent element of its
superset. Read moresource§fn is_in_subset(&self) -> bool
fn is_in_subset(&self) -> bool
self
is actually part of its subset T
(and can be converted to it).source§fn to_subset_unchecked(&self) -> SS
fn to_subset_unchecked(&self) -> SS
self.to_subset
but without any property checks. Always succeeds.source§fn from_subset(element: &SS) -> SP
fn from_subset(element: &SS) -> SP
self
to the equivalent element of its superset.