polars.Expr.list.head

Expr.list.head(n: int | str | Expr = 5) → Expr

Slice the first n values of every sublist.

Parameters:

n

Number of values to return for each sublist.

Examples

>>> df = pl.DataFrame({"a": [[1, 2, 3, 4], [10, 2, 1]]})
>>> df.with_columns(head=pl.col("a").list.head(2))
shape: (2, 2)
┌─────────────┬───────────┐
│ a           ┆ head      │
│ ---         ┆ ---       │
│ list[i64]   ┆ list[i64] │
╞═════════════╪═══════════╡
│ [1, 2, … 4] ┆ [1, 2]    │
│ [10, 2, 1]  ┆ [10, 2]   │
└─────────────┴───────────┘