polars.Expr.to_physical#
- Expr.to_physical() Expr [source]#
Cast to physical representation of the logical dtype.
List(inner)
->List(physical of inner)
Other data types will be left unchanged.
Examples
Replicating the pandas pd.factorize function.
>>> pl.DataFrame({"vals": ["a", "x", None, "a"]}).with_columns( ... pl.col("vals").cast(pl.Categorical), ... pl.col("vals") ... .cast(pl.Categorical) ... .to_physical() ... .alias("vals_physical"), ... ) shape: (4, 2) ┌──────┬───────────────┐ │ vals ┆ vals_physical │ │ --- ┆ --- │ │ cat ┆ u32 │ ╞══════╪═══════════════╡ │ a ┆ 0 │ │ x ┆ 1 │ │ null ┆ null │ │ a ┆ 0 │ └──────┴───────────────┘