polars.arg_sort_by

polars.arg_sort_by(exprs: IntoExpr | Iterable[IntoExpr], *, descending: bool | Sequence[bool] = False) → Expr

Return the row indices that would sort the columns.

Parameters:

exprs

Column(s) to arg sort by. Accepts expression input. Strings are parsed as column names.

descending

Sort in descending order. When sorting by multiple columns, can be specified per column by passing a sequence of booleans.

Examples

Pass a single column name to compute the arg sort by that column.

>>> df = pl.DataFrame(
...     {
...         "a": [0, 1, 1, 0],
...         "b": [3, 2, 3, 2],
...     }
... )
>>> df.select(pl.arg_sort_by("a"))
shape: (4, 1)
┌─────┐
│ a   │
│ --- │
│ u32 │
╞═════╡
│ 0   │
│ 3   │
│ 1   │
│ 2   │
└─────┘

Compute the arg sort by multiple columns by passing a list of columns.

>>> df.select(pl.arg_sort_by(["a", "b"], descending=True))
shape: (4, 1)
┌─────┐
│ a   │
│ --- │
│ u32 │
╞═════╡
│ 2   │
│ 1   │
│ 0   │
│ 3   │
└─────┘