Struct StreamWriter

pub struct StreamWriter<W: Write> { /* private fields */ }

Available on crate feature io_ipc only.

Arrow stream writer

The data written by this writer must be read in order. To signal that no more data is arriving through the stream call self.finish();

For a usage walkthrough consult this example.

Implementations

impl<W: Write> StreamWriter<W>

pub fn new(writer: W, write_options: WriteOptions) -> Self

Creates a new StreamWriter

pub fn set_custom_schema_metadata(&mut self, custom_metadata: Arc<Metadata>)

Sets custom schema metadata. Must be called before start is called

pub fn start( &mut self, schema: &ArrowSchema, ipc_fields: Option<Vec<IpcField>>, ) -> PolarsResult<()>

Starts the stream by writing a Schema message to it. Use ipc_fields to declare dictionary ids in the schema, for dictionary-reuse

pub fn write( &mut self, columns: &RecordBatchT<Box<dyn Array>>, ipc_fields: Option<&[IpcField]>, ) -> PolarsResult<()>

Writes RecordBatchT to the stream

pub fn finish(&mut self) -> PolarsResult<()>

Write continuation bytes, and mark the stream as done

pub fn into_inner(self) -> W

Consumes itself, returning the inner writer.