npy-rs

Numpy format (*.npy) serialization and deserialization.

NPY is a simple binary data format. It stores the type, shape and endianness information in a header, which is followed by a flat binary data field. This crate offers a simple, mostly type-safe way to read and write *.npy files. Files are handled using iterators, so they don't need to fit in memory.

Usage

To use npy-rs, two dependencies must be specified in Cargo.toml:

npy = "0.4"
npy-derive = "0.4"

A typical way to import everything needed is:

#[macro_use]
extern crate npy_derive;
extern crate npy;

The npy-derive dependency is only needed for structured array serialization.

Data can now be imported from a *.npy file:

use npy::NpyData;

std::fs::File::open("data.npy").unwrap().read_to_end(&mut buf).unwrap();
let data: Vec<f64> = NpyData::from_bytes(&buf).unwrap().to_vec();

and exported to a *.npy file:

npy::to_file("data.npy", data).unwrap();

See the documentation for more information.

Several usage examples are available in the examples directory; the simple example shows how to load a file, roundtrip shows both reading and writing. Large files can be memory-mapped as illustrated in the large example.

Documentation