Compress the column data using run-length encoding

Description

Run-length encoding (RLE) encodes data by storing each run of identical values as a single value and its length.

Usage

<Expr>$rle()

Value

A polars expression

Examples

library("polars")

df <- pl$DataFrame(a = c(1, 1, 2, 1, NA, 1, 3, 3))

df$select(pl$col("a")$rle())$unnest("a")

#> shape: (6, 2)
#> ┌─────┬───────┐
#> │ len ┆ value │
#> │ --- ┆ ---   │
#> │ u32 ┆ f64   │
#> ╞═════╪═══════╡
#> │ 2   ┆ 1.0   │
#> │ 1   ┆ 2.0   │
#> │ 1   ┆ 1.0   │
#> │ 1   ┆ null  │
#> │ 1   ┆ 1.0   │
#> │ 2   ┆ 3.0   │
#> └─────┴───────┘