Get the first value of the sub-arrays

Description

Usage

<Expr>$arr$first()

Value

A polars expression

Examples

library("polars")

df <- pl$DataFrame(
  a = list(c(1, 2, 3), c(4, 5, 6))
)$cast(pl$Array(pl$Int64, 3))
df$with_columns(first = pl$col("a")$arr$first())

#> shape: (2, 2)
#> ┌───────────────┬───────┐
#> │ a             ┆ first │
#> │ ---           ┆ ---   │
#> │ array[i64, 3] ┆ i64   │
#> ╞═══════════════╪═══════╡
#> │ [1, 2, 3]     ┆ 1     │
#> │ [4, 5, 6]     ┆ 4     │
#> └───────────────┴───────┘