Projector

datafusion_physical_expr::projection

Struct Projector 

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pub struct Projector { /* private fields */ }
Expand description

Applies a projection to record batches.

A Projector uses a set of projection expressions to transform and a pre-computed output schema to project record batches accordingly.

The main reason to use a Projector is to avoid repeatedly computing the output schema for each batch, which can be costly if the projection expressions are complex.

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impl Projector

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pub fn with_metrics( &self, metrics: &ExecutionPlanMetricsSet, partition: usize, ) -> Self

Construct the projector with metrics. After execution, related metrics will be tracked inside ExecutionPlanMetricsSet

See ExpressionEvaluatorMetrics for details.

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pub fn project_batch(&self, batch: &RecordBatch) -> Result<RecordBatch>

Project a record batch according to this projector’s expressions.

§Errors

This function returns an error if any expression evaluation fails or if the output schema of the resulting record batch does not match the pre-computed output schema of the projector.

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pub fn output_schema(&self) -> &SchemaRef

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pub fn projection(&self) -> &ProjectionExprs

Trait Implementations§

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impl Clone for Projector

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fn clone(&self) -> Projector

Returns a duplicate of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Projector

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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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> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. 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> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. 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.