Struct polars::prelude::IpcReader

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pub struct IpcReader<R>
where R: MmapBytesReader,
{ /* private fields */ }
Available on crate feature polars-io only.
Expand description

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§

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impl<R> IpcReader<R>
where R: MmapBytesReader,

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pub fn schema(&mut self) -> Result<Arc<ArrowSchema>, PolarsError>

Get arrow schema of the Ipc File.

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

Stop reading when n rows are read.

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

Columns to select/ project

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

Add a row index column.

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

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

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

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.

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

Available on crate feature lazy only.

Trait Implementations§

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

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fn new(reader: R) -> IpcReader<R>

Create a new instance of the [SerReader]
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fn set_rechunk(self, rechunk: bool) -> IpcReader<R>

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

Take the SerReader and return a parsed DataFrame.

Auto Trait Implementations§

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

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

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impl<R> Send for IpcReader<R>

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impl<R> Sync for IpcReader<R>

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

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

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V