Struct polars_io::ipc::IpcReader

pub struct IpcReader<R: MmapBytesReader> { /* private fields */ }

Available on crate feature ipc and (crate features ipc or ipc_streaming) only.

Read Arrows IPC format into a DataFrame

Example

use polars_core::prelude::*;
use std::fs::File;
use polars_io::ipc::IpcReader;
use polars_io::SerReader;

fn example() -> PolarsResult<DataFrame> {
    let file = File::open("file.ipc").expect("file not found");

    IpcReader::new(file)
        .finish()
}

Implementations

impl<R: MmapBytesReader> IpcReader<R>

pub fn schema(&mut self) -> PolarsResult<ArrowSchemaRef>

Get arrow schema of the Ipc File.

pub fn with_n_rows(self, num_rows: Option<usize>) -> Self

Stop reading when n rows are read.

pub fn with_columns(self, columns: Option<Vec<String>>) -> Self

Columns to select/ project

pub fn with_row_index(self, row_index: Option<RowIndex>) -> Self

Add a row index column.

pub fn with_projection(self, projection: Option<Vec<usize>>) -> Self

Set the reader’s column projection. This counts from 0, meaning that vec![0, 4] would select the 1st and 5th column.

pub fn memory_mapped(self, path_buf: Option<PathBuf>) -> Self

Set if the file is to be memory_mapped. Only works with uncompressed files. The file name must be passed to register the memory mapped file.

pub fn finish_with_scan_ops( self, predicate: Option<Arc<dyn PhysicalIoExpr>>, verbose: bool ) -> PolarsResult<DataFrame>

Available on crate feature lazy only.

Trait Implementations

impl<R: MmapBytesReader> SerReader<R> for IpcReader<R>

fn new(reader: R) -> Self

Create a new instance of the [SerReader]

fn set_rechunk(self, rechunk: bool) -> Self

Make sure that all columns are contiguous in memory by aggregating the chunks into a single array.

fn finish(self) -> PolarsResult<DataFrame>

Take the SerReader and return a parsed DataFrame.