Return the cumulative count of the non-null values in the column

Description

Return the cumulative count of the non-null values in the column

Usage

<Expr>$cum_count(..., reverse = FALSE)

Arguments

…	These dots are for future extensions and must be empty.
reverse	If TRUE, reverse the count.

Value

A polars expression

Examples

library("polars")

pl$DataFrame(a = 1:4)$with_columns(
  cum_count = pl$col("a")$cum_count(),
  cum_count_reversed = pl$col("a")$cum_count(reverse = TRUE)
)

#> shape: (4, 3)
#> ┌─────┬───────────┬────────────────────┐
#> │ a   ┆ cum_count ┆ cum_count_reversed │
#> │ --- ┆ ---       ┆ ---                │
#> │ i32 ┆ u32       ┆ u32                │
#> ╞═════╪═══════════╪════════════════════╡
#> │ 1   ┆ 1         ┆ 4                  │
#> │ 2   ┆ 2         ┆ 3                  │
#> │ 3   ┆ 3         ┆ 2                  │
#> │ 4   ┆ 4         ┆ 1                  │
#> └─────┴───────────┴────────────────────┘