polars.Expr.get#
- Expr.get(index: int | Expr) Expr [source]#
Return a single value by index.
- Parameters:
- index
An expression that leads to a UInt32 index.
- Returns:
- Expr
Expression of the same data type.
Examples
>>> df = pl.DataFrame( ... { ... "group": [ ... "one", ... "one", ... "one", ... "two", ... "two", ... "two", ... ], ... "value": [1, 98, 2, 3, 99, 4], ... } ... ) >>> df.group_by("group", maintain_order=True).agg(pl.col("value").get(1)) shape: (2, 2) ┌───────┬───────┐ │ group ┆ value │ │ --- ┆ --- │ │ str ┆ i64 │ ╞═══════╪═══════╡ │ one ┆ 98 │ │ two ┆ 99 │ └───────┴───────┘