Struct polars_lazy::frame::LazyGroupBy

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pub struct LazyGroupBy {
    pub logical_plan: LogicalPlan,
    /* private fields */
}
Expand description

Utility struct for lazy group_by operation.

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§logical_plan: LogicalPlan

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impl LazyGroupBy

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pub fn agg<E: AsRef<[Expr]>>(self, aggs: E) -> LazyFrame

Group by and aggregate.

Select a column with col and choose an aggregation. If you want to aggregate all columns use col("*").

§Example
use polars_core::prelude::*;
use polars_lazy::prelude::*;
use arrow::legacy::prelude::QuantileInterpolOptions;

fn example(df: DataFrame) -> LazyFrame {
      df.lazy()
       .group_by_stable([col("date")])
       .agg([
           col("rain").min().alias("min_rain"),
           col("rain").sum().alias("sum_rain"),
           col("rain").quantile(lit(0.5), QuantileInterpolOptions::Nearest).alias("median_rain"),
       ])
}
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pub fn head(self, n: Option<usize>) -> LazyFrame

Return first n rows of each group

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pub fn tail(self, n: Option<usize>) -> LazyFrame

Return last n rows of each group

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pub fn apply<F>(self, f: F, schema: SchemaRef) -> LazyFrame
where F: 'static + Fn(DataFrame) -> PolarsResult<DataFrame> + Send + Sync,

Apply a function over the groups as a new DataFrame.

It is not recommended that you use this as materializing the DataFrame is very expensive.

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impl Clone for LazyGroupBy

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fn clone(&self) -> LazyGroupBy

Returns a copy 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 From<LazyGroupBy> for LazyFrame

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fn from(lgb: LazyGroupBy) -> Self

Converts to this type from the input type.

Auto Trait 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> DynClone for T
where T: Clone,

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fn __clone_box(&self, _: Private) -> *mut ()

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

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fn vzip(self) -> V

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impl<T> Ungil for T
where T: Send,