Struct npyz::NpyWriter

pub struct NpyWriter<Row: Serialize + ?Sized, W: Write> { /* private fields */ }

Interface for writing an NPY file to a data stream.

To construct an instance of this, you must go through the WriterBuilder trait:

use npyz::WriterBuilder;

fn main() -> std::io::Result<()> {
    // Any io::Write is supported.  For this example we'll
    // use Vec<u8> to serialize in-memory.
    let mut out_buf = vec![];
    let mut writer = {
        npyz::WriteOptions::new()
            .default_dtype()
            .shape(&[2, 3])
            .writer(&mut out_buf)
            .begin_nd()?
    };

    writer.push(&100)?;
    writer.push(&101)?;
    writer.push(&102)?;
    // can write elements from iterators too
    writer.extend(vec![200, 201, 202])?;
    writer.finish()?;

    eprintln!("{:02x?}", out_buf);
    Ok(())
}

Implementations

impl<Row: AutoSerialize> NpyWriter<Row, BufWriter<File>>

pub fn open<P: AsRef<Path>>(path: P) -> Result<Self>

👎Deprecated since 0.5.0: Doesn’t carry its weight. Use to_file_1d instead, or replicate the original behavior with Builder::new().default_dtype().begin_1d(std::io::BufWriter::new(std::fs::File::create(path)?))

Create a file, using the default format for the given type.

impl<Row: Serialize> NpyWriter<Row, BufWriter<File>>

pub fn close(self) -> Result<()>

👎Deprecated since 0.5.0: use .finish() instead

Finish writing the file and close it. Alias for NpyWriter::finish.

If omitted, the file will be closed on drop automatically, ignoring any errors encountered during the process.

impl<Row: Serialize + ?Sized, W: Write> NpyWriter<Row, W>

pub fn push(&mut self, row: &Row) -> Result<()>

Append a single row to the file

pub fn extend(&mut self, rows: impl IntoIterator<Item = Row>) -> Result<()>

where Row: Sized,

Write an iterator to the file

pub fn finish(self) -> Result<()>

Finish writing the file.

If no shape was provided, this will update the header to reflect the number of elements written. If a shape was provided and the number of inserted elements is incorrect, an error is returned.

This is automatically called on drop, but in that case, errors are ignored.

Trait Implementations

impl<Row: Serialize + ?Sized, W: Write> Drop for NpyWriter<Row, W>

fn drop(&mut self)

Executes the destructor for this type.