Map values to run IDs

Source code

Description

Similar to $rle(), but it maps each value to an ID corresponding to the run into which it falls. This is especially useful when you want to define groups by runs of identical values rather than the values themselves. Note that the ID is 0-indexed.

Usage

<Expr>$rle_id()

Value

Expr

Examples

library("polars")

df = pl$DataFrame(a = c(1, 2, 1, 1, 1, 4))
df$with_columns(a_r = pl$col("a")$rle_id())

#> shape: (6, 2)
#> ┌─────┬─────┐
#> │ a   ┆ a_r │
#> │ --- ┆ --- │
#> │ f64 ┆ u32 │
#> ╞═════╪═════╡
#> │ 1.0 ┆ 0   │
#> │ 2.0 ┆ 1   │
#> │ 1.0 ┆ 2   │
#> │ 1.0 ┆ 2   │
#> │ 1.0 ┆ 2   │
#> │ 4.0 ┆ 3   │
#> └─────┴─────┘