polars.Expr.list.get

Expr.list.get(index: int | Expr | str, *, null_on_oob: bool = False) → Expr

Get the value by index in the sublists.

So index 0 would return the first item of every sublist and index -1 would return the last item of every sublist if an index is out of bounds, it will return a None.

Parameters:

index

Index to return per sublist

null_on_oob

Behavior if an index is out of bounds: True -> set as null False -> raise an error

Examples

>>> df = pl.DataFrame({"a": [[3, 2, 1], [], [1, 2]]})
>>> df.with_columns(get=pl.col("a").list.get(0, null_on_oob=True))
shape: (3, 2)
┌───────────┬──────┐
│ a         ┆ get  │
│ ---       ┆ ---  │
│ list[i64] ┆ i64  │
╞═══════════╪══════╡
│ [3, 2, 1] ┆ 3    │
│ []        ┆ null │
│ [1, 2]    ┆ 1    │
└───────────┴──────┘