Trait FromPyObject

pub trait FromPyObject<'s>: Sized {
    // Required method
    fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>;
}

FromPyObject is implemented by various types that can be extracted from a Python object.

Normal usage is through the PyObject::extract helper method:

let value = obj.extract::<TargetType>(py)?;

Each target type for this conversion supports a different Python objects as input. Calls with an unsupported input object will result in an exception (usually a TypeError).

This trait is also used by the py_fn! and py_class! and py_argparse! macros in order to translate from Python objects to the expected Rust parameter types. For example, the parameter x in def method(self, x: i32) will use impl FromPyObject for i32 to convert the input Python object into a Rust i32. When these macros are used with reference parameters (x: &str), the trait RefFromPyObject is used instead.

Required Methods

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Extracts Self from the source PyObject.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<'s> FromPyObject<'s> for Cow<'s, str>

Allows extracting strings from Python objects. Accepts Python str and unicode objects. In Python 2.7, str is expected to be UTF-8 encoded.

Returns a UnicodeDecodeError if the input is not valid unicode (containing unpaired surrogates, or a Python 2.7 byte string that is not valid UTF-8).

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s> FromPyObject<'s> for Cow<'s, [u8]>

For Python bytes, returns a reference to the existing immutable string data. If the Python object is a single-dimensional buffer of format c or B (C: char or unsigned char), returns an owned copy of the data in the buffer. Otherwise, uses the sequence protocol and converts each individual element via impl FromPyObject for u8.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s> FromPyObject<'s> for bool

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts a Python bool to a rust bool.

Fails with TypeError if the input is not a Python bool.

impl<'s> FromPyObject<'s> for f32

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python float to Rust f32.

This conversion loses precision as the 64-bit float from Python gets converted to a 32-bit float. Out-of-range numbers may also overflow to infinity.

impl<'s> FromPyObject<'s> for f64

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python float to Rust f64.

impl<'s> FromPyObject<'s> for i8

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for i16

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for i32

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for i64

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for isize

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for u8

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for u16

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for u32

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for u64

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<u64>

impl<'s> FromPyObject<'s> for usize

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Converts Python integers to Rust integers.

Returns OverflowError if the input integer does not fit the Rust type; or TypeError if the input is not an integer.

impl<'s> FromPyObject<'s> for String

Allows extracting strings from Python objects. Accepts Python str and unicode objects. In Python 2.7, str is expected to be UTF-8 encoded.

Returns a UnicodeDecodeError if the input is not valid unicode (containing unpaired surrogates, or a Python 2.7 byte string that is not valid UTF-8).

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>> FromPyObject<'s> for (A,)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>> FromPyObject<'s> for (A, B)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>> FromPyObject<'s> for (A, B, C)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>, D: FromPyObject<'s>> FromPyObject<'s> for (A, B, C, D)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>, D: FromPyObject<'s>, E: FromPyObject<'s>> FromPyObject<'s> for (A, B, C, D, E)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>, D: FromPyObject<'s>, E: FromPyObject<'s>, F: FromPyObject<'s>> FromPyObject<'s> for (A, B, C, D, E, F)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>, D: FromPyObject<'s>, E: FromPyObject<'s>, F: FromPyObject<'s>, G: FromPyObject<'s>> FromPyObject<'s> for (A, B, C, D, E, F, G)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>, D: FromPyObject<'s>, E: FromPyObject<'s>, F: FromPyObject<'s>, G: FromPyObject<'s>, H: FromPyObject<'s>> FromPyObject<'s> for (A, B, C, D, E, F, G, H)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, A: FromPyObject<'s>, B: FromPyObject<'s>, C: FromPyObject<'s>, D: FromPyObject<'s>, E: FromPyObject<'s>, F: FromPyObject<'s>, G: FromPyObject<'s>, H: FromPyObject<'s>, I: FromPyObject<'s>> FromPyObject<'s> for (A, B, C, D, E, F, G, H, I)

Converts a Python tuple to a Rust tuple.

Note: only accepts Python tuple (or derived classes); other types are not accepted.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, T> FromPyObject<'s> for Option<T>

where T: FromPyObject<'s>,

If the python value is None, returns Option::None. Otherwise, converts the python value to T and returns Some(T).

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

impl<'s, T> FromPyObject<'s> for Vec<T>

where for<'a> T: FromPyObject<'a>,

Uses the sequence protocol and converts each individual element via impl FromPyObject for T.

Note: when using --features nightly, a specialization of this impl may use the buffer protocol to perform a more efficient bulk copy.

fn extract(py: Python<'_>, obj: &'s PyObject) -> PyResult<Self>

Implementors

impl FromPyObject<'_> for PyNone

impl<'s> FromPyObject<'s> for &'s AssertionError

impl<'s> FromPyObject<'s> for &'s AttributeError

impl<'s> FromPyObject<'s> for &'s BaseException

impl<'s> FromPyObject<'s> for &'s BlockingIOError

impl<'s> FromPyObject<'s> for &'s BrokenPipeError

impl<'s> FromPyObject<'s> for &'s BufferError

impl<'s> FromPyObject<'s> for &'s ChildProcessError

impl<'s> FromPyObject<'s> for &'s ConnectionAbortedError

impl<'s> FromPyObject<'s> for &'s ConnectionError

impl<'s> FromPyObject<'s> for &'s ConnectionRefusedError

impl<'s> FromPyObject<'s> for &'s ConnectionResetError

impl<'s> FromPyObject<'s> for &'s EOFError

impl<'s> FromPyObject<'s> for &'s EnvironmentError

impl<'s> FromPyObject<'s> for &'s Exception

impl<'s> FromPyObject<'s> for &'s FileExistsError

impl<'s> FromPyObject<'s> for &'s FileNotFoundError

impl<'s> FromPyObject<'s> for &'s FloatingPointError

impl<'s> FromPyObject<'s> for &'s IOError

impl<'s> FromPyObject<'s> for &'s ImportError

impl<'s> FromPyObject<'s> for &'s IndexError

impl<'s> FromPyObject<'s> for &'s InterruptedError

impl<'s> FromPyObject<'s> for &'s IsADirectoryError

impl<'s> FromPyObject<'s> for &'s KeyError

impl<'s> FromPyObject<'s> for &'s KeyboardInterrupt

impl<'s> FromPyObject<'s> for &'s LookupError

impl<'s> FromPyObject<'s> for &'s MemoryError

impl<'s> FromPyObject<'s> for &'s NameError

impl<'s> FromPyObject<'s> for &'s NotADirectoryError

impl<'s> FromPyObject<'s> for &'s NotImplementedError

impl<'s> FromPyObject<'s> for &'s OSError

impl<'s> FromPyObject<'s> for &'s OverflowError

impl<'s> FromPyObject<'s> for &'s PermissionError

impl<'s> FromPyObject<'s> for &'s ProcessLookupError

impl<'s> FromPyObject<'s> for &'s ReferenceError

impl<'s> FromPyObject<'s> for &'s RuntimeError

impl<'s> FromPyObject<'s> for &'s SyntaxError

impl<'s> FromPyObject<'s> for &'s SystemError

impl<'s> FromPyObject<'s> for &'s SystemExit

impl<'s> FromPyObject<'s> for &'s TimeoutError

impl<'s> FromPyObject<'s> for &'s TypeError

impl<'s> FromPyObject<'s> for &'s UnicodeDecodeError

impl<'s> FromPyObject<'s> for &'s UnicodeEncodeError

impl<'s> FromPyObject<'s> for &'s UnicodeTranslateError

impl<'s> FromPyObject<'s> for &'s ValueError

impl<'s> FromPyObject<'s> for &'s ZeroDivisionError

impl<'s> FromPyObject<'s> for &'s PyBool

impl<'s> FromPyObject<'s> for &'s PyBytes

impl<'s> FromPyObject<'s> for &'s PyCapsule

impl<'s> FromPyObject<'s> for &'s PyDict

impl<'s> FromPyObject<'s> for &'s PyFloat

impl<'s> FromPyObject<'s> for &'s PyLong

impl<'s> FromPyObject<'s> for &'s PyList

impl<'s> FromPyObject<'s> for &'s PyModule

impl<'s> FromPyObject<'s> for &'s PyObject

impl<'s> FromPyObject<'s> for &'s PySequence

impl<'s> FromPyObject<'s> for &'s PySet

impl<'s> FromPyObject<'s> for &'s PyTuple

impl<'s> FromPyObject<'s> for &'s PyType

impl<'s> FromPyObject<'s> for &'s PyString

impl<'s> FromPyObject<'s> for AssertionError

impl<'s> FromPyObject<'s> for AttributeError

impl<'s> FromPyObject<'s> for BaseException

impl<'s> FromPyObject<'s> for BlockingIOError

impl<'s> FromPyObject<'s> for BrokenPipeError

impl<'s> FromPyObject<'s> for BufferError

impl<'s> FromPyObject<'s> for ChildProcessError

impl<'s> FromPyObject<'s> for ConnectionAbortedError

impl<'s> FromPyObject<'s> for ConnectionError

impl<'s> FromPyObject<'s> for ConnectionRefusedError

impl<'s> FromPyObject<'s> for ConnectionResetError

impl<'s> FromPyObject<'s> for EOFError

impl<'s> FromPyObject<'s> for EnvironmentError

impl<'s> FromPyObject<'s> for Exception

impl<'s> FromPyObject<'s> for FileExistsError

impl<'s> FromPyObject<'s> for FileNotFoundError

impl<'s> FromPyObject<'s> for FloatingPointError

impl<'s> FromPyObject<'s> for IOError

impl<'s> FromPyObject<'s> for ImportError

impl<'s> FromPyObject<'s> for IndexError

impl<'s> FromPyObject<'s> for InterruptedError

impl<'s> FromPyObject<'s> for IsADirectoryError

impl<'s> FromPyObject<'s> for KeyError

impl<'s> FromPyObject<'s> for KeyboardInterrupt

impl<'s> FromPyObject<'s> for LookupError

impl<'s> FromPyObject<'s> for MemoryError

impl<'s> FromPyObject<'s> for NameError

impl<'s> FromPyObject<'s> for NotADirectoryError

impl<'s> FromPyObject<'s> for NotImplementedError

impl<'s> FromPyObject<'s> for OSError

impl<'s> FromPyObject<'s> for OverflowError

impl<'s> FromPyObject<'s> for PermissionError

impl<'s> FromPyObject<'s> for ProcessLookupError

impl<'s> FromPyObject<'s> for ReferenceError

impl<'s> FromPyObject<'s> for RuntimeError

impl<'s> FromPyObject<'s> for SyntaxError

impl<'s> FromPyObject<'s> for SystemError

impl<'s> FromPyObject<'s> for SystemExit

impl<'s> FromPyObject<'s> for TimeoutError

impl<'s> FromPyObject<'s> for TypeError

impl<'s> FromPyObject<'s> for UnicodeDecodeError

impl<'s> FromPyObject<'s> for UnicodeEncodeError

impl<'s> FromPyObject<'s> for UnicodeTranslateError

impl<'s> FromPyObject<'s> for ValueError

impl<'s> FromPyObject<'s> for ZeroDivisionError

impl<'s> FromPyObject<'s> for NoArgs

impl<'s> FromPyObject<'s> for PyBool

impl<'s> FromPyObject<'s> for PyBytes

impl<'s> FromPyObject<'s> for PyCapsule

impl<'s> FromPyObject<'s> for PyDict

impl<'s> FromPyObject<'s> for PyFloat

impl<'s> FromPyObject<'s> for PyLong

impl<'s> FromPyObject<'s> for PyList

impl<'s> FromPyObject<'s> for PyModule

impl<'s> FromPyObject<'s> for PyObject

impl<'s> FromPyObject<'s> for PySequence

impl<'s> FromPyObject<'s> for PySet

impl<'s> FromPyObject<'s> for PyTuple

impl<'s> FromPyObject<'s> for PyType

impl<'s> FromPyObject<'s> for PyString