Struct pyo3::types::PyByteArray[−][src]

#[repr(transparent)]
pub struct PyByteArray(_);
Expand description

Represents a Python bytearray.

Implementations

Creates a new Python bytearray object.

The byte string is initialized by copying the data from the &[u8].

Creates a new Python bytearray object with an init closure to write its contents. Before calling init the bytearray is zero-initialised.

  • If Python raises a MemoryError on the allocation, new_with will return it inside Err.
  • If init returns Err(e), new_with will return Err(e).
  • If init returns Ok(()), new_with will return Ok(&PyByteArray).

Examples

use pyo3::{prelude::*, types::PyByteArray};
Python::with_gil(|py| -> PyResult<()> {
    let py_bytearray = PyByteArray::new_with(py, 10, |bytes: &mut [u8]| {
        bytes.copy_from_slice(b"Hello Rust");
        Ok(())
    })?;
    let bytearray: &[u8] = unsafe { py_bytearray.as_bytes() };
    assert_eq!(bytearray, b"Hello Rust");
    Ok(())
});

Creates a new Python bytearray object from another PyObject that implements the buffer protocol.

Gets the length of the bytearray.

Checks if the bytearray is empty.

Get the start of the buffer containing the contents of the bytearray.

Note that this bytearray object is both shared and mutable, and the backing buffer may be reallocated if the bytearray is resized. This can occur from Python code as well as from Rust via PyByteArray::resize.

As a result, the returned pointer should be dereferenced only if since calling this method no Python code has executed, PyByteArray::resize has not been called.

Get the contents of this buffer as a slice.

Safety

This bytearray must not be resized or edited while holding the slice.

Safety Detail

This method is equivalent to std::slice::from_raw_parts(self.data(), self.len()), and so all the safety notes of std::slice::from_raw_parts apply here.

In particular, note that this bytearray object is both shared and mutable, and the backing buffer may be reallocated if the bytearray is resized. Mutations can occur from Python code as well as from Rust, via PyByteArray::as_bytes_mut and PyByteArray::resize.

Extreme care should be exercised when using this slice, as the Rust compiler will make optimizations based on the assumption the contents of this slice cannot change. This can easily lead to undefined behavior.

As a result, this slice should only be used for short-lived operations to read this bytearray without executing any Python code, such as copying into a Vec.

Get the contents of this buffer as a mutable slice.

Safety

This slice should only be used for short-lived operations that write to this bytearray without executing any Python code. See the safety note for PyByteArray::as_bytes.

Copies the contents of the bytearray to a Rust vector.

Examples

let bytearray = PyByteArray::new(py, b"Hello World.");
let mut copied_message = bytearray.to_vec();
assert_eq!(b"Hello World.", copied_message.as_slice());

copied_message[11] = b'!';
assert_eq!(b"Hello World!", copied_message.as_slice());

pyo3::py_run!(py, bytearray, "assert bytearray == b'Hello World.'");

Resizes the bytearray object to the new length len.

Note that this will invalidate any pointers obtained by PyByteArray::data, as well as any (unsafe) slices obtained from PyByteArray::as_bytes and PyByteArray::as_bytes_mut.

Methods from Deref<Target = PyAny>

Converts this PyAny to a concrete Python type.

Examples

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

Python::with_gil(|py| {
    let dict = PyDict::new(py);
    assert!(dict.is_instance::<PyAny>().unwrap());
    let any: &PyAny = dict.as_ref();
    assert!(any.downcast::<PyDict>().is_ok());
    assert!(any.downcast::<PyList>().is_err());
});

Determines whether this object has the given attribute.

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

Retrieves an attribute value.

This is equivalent to the Python expression self.attr_name.

Sets an attribute value.

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

Deletes an attribute.

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

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(py, 0_f64);
    let b = PyFloat::new(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(py, 0_f64);
    let b = PyString::new(py, "zero");
    assert!(a.compare(b).is_err());
    Ok(())
})?;

Tests whether two Python objects obey a given CompareOp.

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

compare_opPython expression
CompareOp::Eqself == other
CompareOp::Neself != other
CompareOp::Ltself < other
CompareOp::Leself <= other
CompareOp::Gtself > other
CompareOp::Geself >= other

Examples

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

Python::with_gil(|py| -> PyResult<()> {
    let a: &PyInt = 0_u8.into_py(py).into_ref(py).downcast()?;
    let b: &PyInt = 42_u8.into_py(py).into_ref(py).downcast()?;
    assert!(a.rich_compare(b, CompareOp::Le)?.is_true()?);
    Ok(())
  })?;

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(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.

Calls the object.

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

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(py, "builtins")?;
    let help = module.getattr("help")?;
    help.call0()?;
    Ok(())
})?;

This is equivalent to the Python expression help().

Calls the object with only positional arguments.

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

Examples

use pyo3::prelude::*;

Python::with_gil(|py| -> PyResult<()> {
    let module = PyModule::import(py, "operator")?;
    let add = module.getattr("add")?;
    let args = (1,2);
    let value = add.call1(args)?;
    assert_eq!(value.extract::<i32>()?, 3);
    Ok(())
})?;

This is equivalent to the following Python code:

from operator import add

value = add(1,2)
assert value == 3

Calls a method on the object.

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

Examples

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

Python::with_gil(|py| -> PyResult<()> {
    let list = PyList::new(py, vec![3, 6, 5, 4, 7]);
    let kwargs = vec![("reverse", true)].into_py_dict(py);

    list.call_method("sort", (), Some(kwargs))?;
    assert_eq!(list.extract::<Vec<i32>>()?, vec![7, 6, 5, 4, 3]);
    Ok(())
})?;

This is equivalent to the following Python code:

my_list = [3, 6, 5, 4, 7]
my_list.sort(reverse = True)
assert my_list == [7, 6, 5, 4, 3]

Calls a method on the object without arguments.

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

Examples

use pyo3::prelude::*;
use pyo3::types::PyFloat;
use std::f64::consts::PI;

Python::with_gil(|py| -> PyResult<()> {
    let pi = PyFloat::new(py, PI);
    let ratio = pi.call_method0("as_integer_ratio")?;
    let (a, b) = ratio.extract::<(u64, u64)>()?;
    assert_eq!(a, 884_279_719_003_555);
    assert_eq!(b, 281_474_976_710_656);
    Ok(())
})?;

This is equivalent to the following Python code:

import math

a, b = math.pi.as_integer_ratio()

Calls a method on the object with only positional arguments.

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

Examples

use pyo3::prelude::*;
use pyo3::types::PyList;

Python::with_gil(|py| -> PyResult<()> {
    let list = PyList::new(py, vec![1, 3, 4]);
    list.call_method1("insert", (1, 2))?;
    assert_eq!(list.extract::<Vec<u8>>()?, [1, 2, 3, 4]);
    Ok(())
})?;

This is equivalent to the following Python code:

list_ = [1,3,4]
list_.insert(1,2)
assert list_ == [1,2,3,4]

Returns whether the object is considered to be true.

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

Returns whether the object is considered to be None.

This is equivalent to the Python expression self is None.

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

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

Gets an item from the collection.

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

Sets a collection item value.

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

Deletes an item from the collection.

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

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.

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

Returns the Python type pointer for this object.

Casts the PyObject to a concrete Python object type.

This can cast only to native Python types, not types implemented in Rust.

Extracts some type from the Python object.

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

Returns the reference count for the Python object.

Computes the “repr” representation of self.

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

Computes the “str” representation of self.

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

Retrieves the hash code of self.

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

Returns the length of the sequence or mapping.

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

Returns the list of attributes of this object.

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

Checks whether this object is an instance of type T.

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

Trait Implementations

Gets the underlying FFI pointer, returns a borrowed pointer.

Performs the conversion.

Formats the value using the given formatter. Read more

The resulting type after dereferencing.

Dereferences the value.

Formats the value using the given formatter. Read more

Performs the conversion.

Performs the conversion.

Extracts Self from the source PyObject.

Performs the conversion.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Cast &PyAny to &Self without no type checking. Read more

Utility type to make Py::as_ref work

Class name

Module name, if any

PyTypeObject instance for this type.

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

Checks if object is an instance of this type.

Converts self into a Python object.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Convert from an arbitrary PyObject. Read more

Convert from an arbitrary borrowed PyObject. Read more

Convert from an arbitrary PyObject or panic. Read more

Convert from an arbitrary PyObject or panic. Read more

Convert from an arbitrary PyObject. Read more

Convert from an arbitrary borrowed PyObject. Read more

Convert from an arbitrary borrowed PyObject. Read more

Convert from an arbitrary borrowed PyObject. Read more

Performs the conversion.

Cast from a concrete Python object type to PyObject.

Cast from a concrete Python object type to PyObject. With exact type check.

Cast a PyAny to a specific type of PyObject. The caller must have already verified the reference is for this type. Read more

Returns the safe abstraction over the type object.

Converts self into a Python object and calls the specified closure on the native FFI pointer underlying the Python object. Read more

Converts the given value to a String. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.