Struct ParquetWriter

pub struct ParquetWriter<W> { /* private fields */ }

Available on crate feature polars-io only.

Write a DataFrame to Parquet format.

Implementations

impl<W> ParquetWriter<W>

where W: Write,

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

where W: Write,

Create a new writer

pub fn with_compression( self, compression: ParquetCompression, ) -> ParquetWriter<W>

Set the compression used. Defaults to Zstd.

The default compression Zstd has very good performance, but may not yet been supported by older readers. If you want more compatibility guarantees, consider using Snappy.

pub fn with_statistics(self, statistics: StatisticsOptions) -> ParquetWriter<W>

Compute and write statistic

pub fn with_row_group_size(self, size: Option<usize>) -> ParquetWriter<W>

Set the row group size (in number of rows) during writing. This can reduce memory pressure and improve writing performance.

pub fn with_data_page_size(self, limit: Option<usize>) -> ParquetWriter<W>

Sets the maximum bytes size of a data page. If None will be 1024^2 bytes.

pub fn set_parallel(self, parallel: bool) -> ParquetWriter<W>

Serialize columns in parallel

pub fn with_key_value_metadata( self, key_value_metadata: Option<KeyValueMetadata>, ) -> ParquetWriter<W>

Set custom file-level key value metadata for the Parquet file

pub fn with_context_info( self, context_info: Option<HashMap<String, String, RandomState>>, ) -> ParquetWriter<W>

Set context information for the writer

pub fn batched( self, schema: &Schema<DataType>, ) -> Result<BatchedWriter<W>, PolarsError>

pub fn finish(self, df: &mut DataFrame) -> Result<u64, PolarsError>

Write the given DataFrame in the writer W. Returns the total size of the file.