polars_io::ipc

Struct IpcStreamReader

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pub struct IpcStreamReader<R> { /* private fields */ }
Available on crate feature ipc_streaming and (crate features ipc or ipc_streaming) only.
Expand description

Read Arrows Stream IPC format into a DataFrame

§Example

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

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

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

Implementations§

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impl<R: Read> IpcStreamReader<R>

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

Get schema of the Ipc Stream File

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pub fn arrow_schema(&mut self) -> PolarsResult<ArrowSchema>

Get arrow schema of the Ipc Stream File, this is faster than creating a polars schema.

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pub fn custom_metadata(&mut self) -> PolarsResult<Option<Arc<Metadata>>>

Get schema-level custom metadata of the Ipc Stream file

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

Stop reading when n rows are read.

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

Columns to select/ project

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

Add a row index column.

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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.

Trait Implementations§

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impl<R> SerReader<R> for IpcStreamReader<R>
where R: Read,

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fn new(reader: R) -> Self

Create a new instance of the SerReader
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fn set_rechunk(self, rechunk: bool) -> Self

Make sure that all columns are contiguous in memory by aggregating the chunks into a single array.
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fn finish(self) -> PolarsResult<DataFrame>

Take the SerReader and return a parsed DataFrame.

Auto Trait Implementations§

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impl<R> Freeze for IpcStreamReader<R>
where R: Freeze,

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impl<R> RefUnwindSafe for IpcStreamReader<R>
where R: RefUnwindSafe,

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impl<R> Send for IpcStreamReader<R>
where R: Send,

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impl<R> Sync for IpcStreamReader<R>
where R: Sync,

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impl<R> Unpin for IpcStreamReader<R>
where R: Unpin,

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impl<R> UnwindSafe for IpcStreamReader<R>
where R: UnwindSafe,

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impl<T> Any for T
where T: 'static + ?Sized,

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Gets the TypeId of self. Read more
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where T: ?Sized,

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where T: ?Sized,

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