daft.functions.over#

def over(expr: Expression, window: Window) -> Expression:
    """Apply the expression as a window function.

    Args:
        expr: The expression to apply as a window function.
        window: The window specification (created using ``daft.Window``)
            defining partitioning, ordering, and framing.

    Examples:
        >>> import daft
        >>> from daft.functions import sum
        >>>
        >>> df = daft.from_pydict(
        ...     {
        ...         "group": ["A", "A", "A", "B", "B", "B"],
        ...         "date": ["2020-01-01", "2020-01-02", "2020-01-03", "2020-01-04", "2020-01-05", "2020-01-06"],
        ...         "value": [1, 2, 3, 4, 5, 6],
        ...     }
        ... )
        >>> window_spec = daft.Window().partition_by("group").order_by("date")
        >>> df = df.with_column("grouped_sum", sum(df["value"]).over(window_spec))
        >>> df.sort(["group", "date"]).show()
        ╭────────┬────────────┬───────┬─────────────╮
        │ group  ┆ date       ┆ value ┆ grouped_sum │
        │ ---    ┆ ---        ┆ ---   ┆ ---         │
        │ String ┆ String     ┆ Int64 ┆ Int64       │
        ╞════════╪════════════╪═══════╪═════════════╡
        │ A      ┆ 2020-01-01 ┆ 1     ┆ 6           │
        ├╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ A      ┆ 2020-01-02 ┆ 2     ┆ 6           │
        ├╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ A      ┆ 2020-01-03 ┆ 3     ┆ 6           │
        ├╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ B      ┆ 2020-01-04 ┆ 4     ┆ 15          │
        ├╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ B      ┆ 2020-01-05 ┆ 5     ┆ 15          │
        ├╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
        │ B      ┆ 2020-01-06 ┆ 6     ┆ 15          │
        ╰────────┴────────────┴───────┴─────────────╯
        <BLANKLINE>
        (Showing first 6 of 6 rows)

    Returns:
        Expression: The result of applying this expression as a window function.
    """
    return Expression._from_pyexpr(expr._expr.over(window._spec))