patito.Relation.order

Relation.order(by)

Change the order of the rows of the relation.

Parameters

by (Union[str, Iterable[str]]) – An ORDER BY SQL expression such as "age DESC" or ("age DESC", "name ASC").

Return type

TypeVar(RelationType, bound= Relation)

Returns

New relation where the rows have been ordered according to by.

Example

>>> import patito as pt
>>> df = pt.DataFrame(
...     {
...         "name": ["Alice", "Bob", "Charles", "Diana"],
...         "age": [20, 20, 30, 35],
...     }
... )
>>> df
shape: (4, 2)
┌─────────┬─────┐
│ name    ┆ age │
│ ---     ┆ --- │
│ str     ┆ i64 │
╞═════════╪═════╡
│ Alice   ┆ 20  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Bob     ┆ 20  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Charles ┆ 30  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Diana   ┆ 35  │
└─────────┴─────┘
>>> relation = pt.Relation(df)
>>> relation.order(by="age desc").to_df()
shape: (4, 2)
┌─────────┬─────┐
│ name    ┆ age │
│ ---     ┆ --- │
│ str     ┆ i64 │
╞═════════╪═════╡
│ Diana   ┆ 35  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Charles ┆ 30  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Alice   ┆ 20  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Bob     ┆ 20  │
└─────────┴─────┘
>>> relation.order(by=["age desc", "name desc"]).to_df()
shape: (4, 2)
┌─────────┬─────┐
│ name    ┆ age │
│ ---     ┆ --- │
│ str     ┆ i64 │
╞═════════╪═════╡
│ Diana   ┆ 35  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Charles ┆ 30  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Bob     ┆ 20  │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┤
│ Alice   ┆ 20  │
└─────────┴─────┘