polars.Expr.name.to_lowercase

Expr.name.to_lowercase() → Expr

Make the root column name lowercase.

See also

prefix

suffix

to_uppercase

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

>>> df = pl.DataFrame(
...     {
...         "ColX": [1, 2, 3],
...         "ColY": ["x", "y", "z"],
...     }
... )
>>> df.with_columns(pl.all().name.to_lowercase())
shape: (3, 4)
┌──────┬──────┬──────┬──────┐
│ ColX ┆ ColY ┆ colx ┆ coly │
│ ---  ┆ ---  ┆ ---  ┆ ---  │
│ i64  ┆ str  ┆ i64  ┆ str  │
╞══════╪══════╪══════╪══════╡
│ 1    ┆ x    ┆ 1    ┆ x    │
│ 2    ┆ y    ┆ 2    ┆ y    │
│ 3    ┆ z    ┆ 3    ┆ z    │
└──────┴──────┴──────┴──────┘