# PyO3
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[](https://codecov.io/gh/PyO3/pyo3)
[](https://crates.io/crates/pyo3)
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[Rust](http://www.rust-lang.org/) bindings for [Python](https://www.python.org/). This includes running and interacting with python code from a rust binaries as well as writing native python modules.
* User Guide: [stable](https://pyo3.rs) | [master](https://pyo3.rs/master)
* API Documentation: [master](https://pyo3.rs/master/doc)
A comparison with rust-cpython can be found [in the guide](https://pyo3.rs/master/rust-cpython.html).
## Usage
PyO3 supports python 2.7 as well as python 3.5 and up. The minimum required rust version is 1.34.0-nightly 2019-02-06.
You can either write a native python module in rust or use python from a rust binary.
On some OSs, you need some additional packages.
E.g. if you are on Ubuntu18.04, please run
```bash
sudo apt install python3-dev python-dev
```
## Using rust from python
PyO3 can be used to generate a native python module.
**`Cargo.toml`**
```toml
[package]
name = "string-sum"
version = "0.1.0"
edition = "2018"
[lib]
name = "string_sum"
crate-type = ["cdylib"]
[dependencies.pyo3]
version = "0.6.0-alpha.4"
features = ["extension-module"]
```
**`src/lib.rs`**
```rust
// Not required when using Rust 2018
extern crate pyo3;
use pyo3::prelude::*;
use pyo3::wrap_pyfunction;
#[pyfunction]
/// Formats the sum of two numbers as string
fn sum_as_string(a: usize, b: usize) -> PyResult<String> {
Ok((a + b).to_string())
}
/// This module is a python module implemented in Rust.
#[pymodule]
fn string_sum(py: Python, m: &PyModule) -> PyResult<()> {
m.add_wrapped(wrap_pyfunction!(sum_as_string))?;
Ok(())
}
```
On windows and linux, you can build normally with `cargo build --release`. On macOS, you need to set additional linker arguments. One option is to compile with `cargo rustc --release -- -C link-arg=-undefined -C link-arg=dynamic_lookup`, the other is to create a `.cargo/config` with the following content:
```toml
[target.x86_64-apple-darwin]
rustflags = [
"-C", "link-arg=-undefined",
"-C", "link-arg=dynamic_lookup",
]
```
For developing, you can copy and rename the shared library from the target folder: On macOS, rename `libstring_sum.dylib` to `string_sum.so`, on windows `libstring_sum.dll` to `string_sum.pyd` and on linux `libstring_sum.so` to `string_sum.so`. Then open a python shell in the same folder and you'll be able to `import string_sum`.
To build, test and publish your crate as python module, you can use [pyo3-pack](https://github.com/PyO3/pyo3-pack) or [setuptools-rust](https://github.com/PyO3/setuptools-rust). You can find an example for setuptools-rust in [examples/word-count](examples/word-count), while pyo3-pack should work on your crate without any configuration.
## Using python from rust
Add `pyo3` this to your `Cargo.toml`:
```toml
[dependencies]
pyo3 = "0.6.0-alpha.4"
```
Example program displaying the value of `sys.version`:
```rust
// Not required when using Rust 2018
extern crate pyo3;
use pyo3::prelude::*;
use pyo3::types::IntoPyDict;
fn main() -> PyResult<()> {
let gil = Python::acquire_gil();
let py = gil.python();
let sys = py.import("sys")?;
let version: String = sys.get("version")?.extract()?;
let locals = [("os", py.import("os")?)].into_py_dict(py);
let code = "os.getenv('USER') or os.getenv('USERNAME') or 'Unknown'";
let user: String = py.eval(code, None, Some(&locals))?.extract()?;
println!("Hello {}, I'm Python {}", user, version);
Ok(())
}
```
## Examples and tooling
* [examples/word-count](examples/word-count) _Counting the occurrences of a word in a text file_
* [hyperjson](https://github.com/mre/hyperjson) _A hyper-fast Python module for reading/writing JSON data using Rust's serde-json_
* [rust-numpy](https://github.com/rust-numpy/rust-numpy) _Rust binding of NumPy C-API_
* [html-py-ever](https://github.com/PyO3/setuptools-rust/tree/master/html-py-ever) _Using [html5ever](https://github.com/servo/html5ever) through [kuchiki](https://github.com/kuchiki-rs/kuchiki) to speed up html parsing and css-selecting._
* [pyo3-built](https://github.com/PyO3/pyo3-built) _Simple macro to expose metadata obtained with the [`built`](https://crates.io/crates/built) crate as a [`PyDict`](https://pyo3.github.io/pyo3/pyo3/struct.PyDict.html)_
* [point-process](https://github.com/ManifoldFR/point-process-rust/tree/master/pylib) _High level API for pointprocesses as a Python library_
* [autopy](https://github.com/autopilot-rs/autopy) _A simple, cross-platform GUI automation library for Python and Rust._
* [orjson](https://github.com/ijl/orjson) _Fast Python JSON library_
## License
PyO3 is licensed under the [Apache-2.0 license](http://opensource.org/licenses/APACHE-2.0).
Python is licensed under the [Python License](https://docs.python.org/2/license.html).