polars.Expr.meta.root_names

Expr.meta.root_names() → list[str]

Get a list with the root column name.

Examples

>>> e = pl.col("foo") * pl.col("bar")
>>> e.meta.root_names()
['foo', 'bar']
>>> e_filter = pl.col("foo").filter(pl.col("bar") == 13)
>>> e_filter.meta.root_names()
['foo', 'bar']
>>> e_sum_over = pl.sum("foo").over("groups")
>>> e_sum_over.meta.root_names()
['foo', 'groups']
>>> e_sum_slice = pl.sum("foo").slice(pl.len() - 10, pl.col("bar"))
>>> e_sum_slice.meta.root_names()
['foo', 'bar']