Struct polars_io::avro::AvroReader

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pub struct AvroReader<R> { /* private fields */ }
Available on crate feature avro only.
Expand description

Read Apache Avro format into a DataFrame

§Example

use std::fs::File;
use polars_core::prelude::*;
use polars_io::avro::AvroReader;
use polars_io::SerReader;

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

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

Implementations§

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impl<R: Read + Seek> AvroReader<R>

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

Get schema of the Avro File

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

Get arrow schema of the avro File, this is faster than a polars schema.

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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_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.

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

Columns to select/ project

Trait Implementations§

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impl<R> SerReader<R> for AvroReader<R>
where R: Read + Seek,

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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 AvroReader<R>
where R: Freeze,

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

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

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

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

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impl<R> UnwindSafe for AvroReader<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> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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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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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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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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type Output = T

Should always be Self
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where U: Into<T>,

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type Error = Infallible

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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

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

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

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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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fn vzip(self) -> V

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where S: Into<Dispatch>,

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