Struct NpzWriter

pub struct NpzWriter<W: Write + Seek> { /* private fields */ }

Writer for .npz files.

Note that the inner ZipWriter is wrapped in a BufWriter when writing each array with .add_array(). If desired, you could additionally buffer the innermost writer (e.g. the File when writing to a file) by wrapping it in a BufWriter. This may be somewhat beneficial if the arrays are large and have non-standard layouts but may decrease performance if the arrays have standard or Fortran layout, so it’s not recommended without testing to compare.

Example

use ndarray_npz::{
	ndarray::{array, aview0, Array1, Array2},
	NpzWriter,
};
use std::fs::File;

let mut npz = NpzWriter::new(File::create("arrays.npz")?);
let a: Array2<i32> = array![[1, 2, 3], [4, 5, 6]];
let b: Array1<i32> = array![7, 8, 9];
npz.add_array("a", &a)?;
npz.add_array("b", &b)?;
npz.add_array("c", &aview0(&10))?;
npz.finish()?;

Implementations

impl<W: Write + Seek> NpzWriter<W>

pub fn new(writer: W) -> NpzWriter<W>

Creates a new .npz file without compression. See numpy.savez.

Ensures .npy files are 64-byte aligned for memory-mapping via NpzView/NpzViewMut.

pub fn new_compressed(writer: W) -> NpzWriter<W>

Available on crate feature compressed only.

Creates a new .npz file with compression. See numpy.savez_compressed.

pub fn add_array<N, S, D>( &mut self, name: N, array: &ArrayBase<S, D>, ) -> Result<(), WriteNpzError>

where N: Into<String>, S::Elem: WritableElement, S: Data, D: Dimension,

Adds an array with the specified name to the .npz file.

To write a scalar value, create a zero-dimensional array using arr0 or aview0.

Errors

Adding an array can fail with WriteNpyError.

pub fn finish(self) -> Result<W, WriteNpzError>

Calls .finish() on the zip file and .flush() on the writer, and then returns the writer.

This finishes writing the remaining zip structures and flushes the writer. While dropping will automatically attempt to finish the zip file and (for writers that flush on drop, such as BufWriter) flush the writer, any errors that occur during drop will be silently ignored. So, it’s necessary to call .finish() to properly handle errors.

Errors

Finishing the zip archive can fail with ZipError.