Operations on Polars DataFrame grouped by rolling windows

Description

This class comes from \<DataFrame>$rolling().

Examples

library(polars)

df = pl$DataFrame(
  dt = c("2020-01-01", "2020-01-01", "2020-01-01", "2020-01-02", "2020-01-03", "2020-01-08"),
  a = c(3, 7, 5, 9, 2, 1)
)$with_columns(
  pl$col("dt")$str$strptime(pl$Date, format = NULL)$set_sorted()
)

df$rolling(index_column = "dt", period = "2d")

#> shape: (6, 2)
#> ┌────────────┬─────┐
#> │ dt         ┆ a   │
#> │ ---        ┆ --- │
#> │ date       ┆ f64 │
#> ╞════════════╪═════╡
#> │ 2020-01-01 ┆ 3.0 │
#> │ 2020-01-01 ┆ 7.0 │
#> │ 2020-01-01 ┆ 5.0 │
#> │ 2020-01-02 ┆ 9.0 │
#> │ 2020-01-03 ┆ 2.0 │
#> │ 2020-01-08 ┆ 1.0 │
#> └────────────┴─────┘