Trait polars_core::chunked_array::ops::ChunkApply

pub trait ChunkApply<'a, A, B> {
    fn apply_cast_numeric<F, S>(&'a self, f: F) -> ChunkedArray<S>
    where
        F: Fn(A) -> S::Native + Copy,
        S: PolarsNumericType;
    fn branch_apply_cast_numeric_no_null<F, S>(
        &'a self, 
        f: F
    ) -> ChunkedArray<S>
    where
        F: Fn(Option<A>) -> S::Native + Copy,
        S: PolarsNumericType;
    fn apply<F>(&'a self, f: F) -> Self
    where
        F: Fn(A) -> B + Copy;
    fn try_apply<F>(&'a self, f: F) -> Result<Self>
    where
        F: Fn(A) -> Result<B> + Copy,
        Self: Sized;
    fn apply_on_opt<F>(&'a self, f: F) -> Self
    where
        F: Fn(Option<A>) -> Option<B> + Copy;
    fn apply_with_idx<F>(&'a self, f: F) -> Self
    where
        F: Fn((usize, A)) -> B + Copy;
    fn apply_with_idx_on_opt<F>(&'a self, f: F) -> Self
    where
        F: Fn((usize, Option<A>)) -> Option<B> + Copy;
    fn apply_to_slice<F, T>(&'a self, f: F, slice: &mut [T])
    where
        F: Fn(Option<A>, &T) -> T;
}

Fastest way to do elementwise operations on a ChunkedArray when the operation is cheaper than branching due to null checking

Required methods

fn apply_cast_numeric<F, S>(&'a self, f: F) -> ChunkedArray<S> where
    F: Fn(A) -> S::Native + Copy,
    S: PolarsNumericType, 

Apply a closure elementwise and cast to a Numeric ChunkedArray. This is fastest when the null check branching is more expensive than the closure application.

Null values remain null.

fn branch_apply_cast_numeric_no_null<F, S>(&'a self, f: F) -> ChunkedArray<S> where
    F: Fn(Option<A>) -> S::Native + Copy,
    S: PolarsNumericType, 

Apply a closure on optional values and cast to Numeric ChunkedArray without null values.

fn apply<F>(&'a self, f: F) -> Self where
    F: Fn(A) -> B + Copy, 

Apply a closure elementwise. This is fastest when the null check branching is more expensive than the closure application. Often it is.

Null values remain null.

Example

use polars_core::prelude::*;
fn double(ca: &UInt32Chunked) -> UInt32Chunked {
    ca.apply(|v| v * 2)
}

fn try_apply<F>(&'a self, f: F) -> Result<Self> where
    F: Fn(A) -> Result<B> + Copy,
    Self: Sized, 

fn apply_on_opt<F>(&'a self, f: F) -> Self where
    F: Fn(Option<A>) -> Option<B> + Copy, 

Apply a closure elementwise including null values.

fn apply_with_idx<F>(&'a self, f: F) -> Self where
    F: Fn((usize, A)) -> B + Copy, 

Apply a closure elementwise. The closure gets the index of the element as first argument.

fn apply_with_idx_on_opt<F>(&'a self, f: F) -> Self where
    F: Fn((usize, Option<A>)) -> Option<B> + Copy, 

Apply a closure elementwise. The closure gets the index of the element as first argument.

fn apply_to_slice<F, T>(&'a self, f: F, slice: &mut [T]) where
    F: Fn(Option<A>, &T) -> T, 

Apply a closure elementwise and write results to a mutable slice.

Implementors

impl<'a> ChunkApply<'a, &'a str, Cow<'a, str>> for Utf8Chunked

impl<'a> ChunkApply<'a, bool, bool> for BooleanChunked

impl<'a> ChunkApply<'a, Series, Series> for ListChunked

impl<'a, T> ChunkApply<'a, <T as PolarsNumericType>::Native, <T as PolarsNumericType>::Native> for ChunkedArray<T> where
    T: PolarsNumericType, 

impl<'a, T> ChunkApply<'a, &'a T, T> for ObjectChunked<T> where
    T: PolarsObject, 

This is supported on crate feature object only.