polars.Expr.arr.first

Expr.arr.first() → Expr

Get the first value of the sublists.

Examples

>>> df = pl.DataFrame({"foo": [[3, 2, 1], [], [1, 2]]})
>>> df.select(pl.col("foo").arr.first())
shape: (3, 1)
┌──────┐
│ foo  │
│ ---  │
│ i64  │
╞══════╡
│ 3    │
│ null │
│ 1    │
└──────┘