polars.Expr.name.keep

Expr.name.keep() → Expr

Keep the original root name of the expression.

See also

Expr.alias

map

Notes

This will undo any previous renaming operations on the expression.

Due to implementation constraints, this method can only be called as the last expression in a chain. Only one name operation per expression will work. Consider using .name.map for advanced renaming.

Examples

Prevent errors due to potential duplicate column names.

>>> df = pl.DataFrame(
...     {
...         "a": [1, 2],
...         "b": [3, 4],
...     }
... )
>>> df.select((pl.lit(10) / pl.all()).name.keep())
shape: (2, 2)
┌──────┬──────────┐
│ a    ┆ b        │
│ ---  ┆ ---      │
│ f64  ┆ f64      │
╞══════╪══════════╡
│ 10.0 ┆ 3.333333 │
│ 5.0  ┆ 2.5      │
└──────┴──────────┘

Undo an alias operation.

>>> df.with_columns((pl.col("a") * 9).alias("c").name.keep())
shape: (2, 2)
┌─────┬─────┐
│ a   ┆ b   │
│ --- ┆ --- │
│ i64 ┆ i64 │
╞═════╪═════╡
│ 9   ┆ 3   │
│ 18  ┆ 4   │
└─────┴─────┘