patito.Relation.aggregate

Relation.aggregate(*aggregations, group_by, **named_aggregations)

Return relation formed by GROUP BY SQL aggregation(s).

Parameters

  • aggregations (str) – Zero or more aggregation expressions such as “sum(column_name)” and “count(distinct column_name)”.

  • named_aggregations (str) – Zero or more aggregated expressions where the keyword is used to name the given aggregation. For example, my_column="sum(column_name)" is inserted as "sum(column_name) as my_column" in the executed SQL query.

  • group_by (Union[str, Iterable[str]]) – A single column name or iterable collection of column names to group by.

Examples

>>> import patito as pt
>>> df = pt.DataFrame({"a": [1, 2, 3], "b": ["X", "Y", "X"]})
>>> relation = pt.Relation(df)
>>> relation.aggregate(
...     "b",
...     "sum(a)",
...     "greatest(b)",
...     max_a="max(a)",
...     group_by="b",
... ).to_df()
shape: (2, 4)
┌─────┬────────┬─────────────┬───────┐
│ b   ┆ sum(a) ┆ greatest(b) ┆ max_a │
│ --- ┆ ---    ┆ ---         ┆ ---   │
│ str ┆ f64    ┆ str         ┆ i64   │
╞═════╪════════╪═════════════╪═══════╡
│ X   ┆ 4.0    ┆ X           ┆ 3     │
├╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┤
│ Y   ┆ 2.0    ┆ Y           ┆ 2     │
└─────┴────────┴─────────────┴───────┘
Return type

Relation